vendor: update prometheus deps to match docker/docker

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

vendor.conf

@@ -2,6 +2,7 @@ cloud.google.com/go                                 0ebda48a7f143b1cce9eb37a8c11
 github.com/agl/ed25519                              5312a61534124124185d41f09206b9fef1d88403
 github.com/Azure/go-ansiterm                        d6e3b3328b783f23731bc4d058875b0371ff8109
 github.com/beorn7/perks                             37c8de3658fcb183f997c4e13e8337516ab753e6 # v1.0.1
+github.com/cespare/xxhash/v2                        d7df74196a9e781ede915320c11c378c1b2f3a1f # v2.1.1
 github.com/containerd/console                       8375c3424e4d7b114e8a90a4a40c8e1b40d1d4e6 # v1.0.0
 github.com/containerd/containerd                    e9f94064b9616ab36a8a51d632a63f97f7783c3d # v1.4.0-rc.1
 github.com/containerd/continuity                    efbc4488d8fe1bdc16bde3b2d2990d9b3a899165
@@ -17,7 +18,7 @@ github.com/docker/docker-credential-helpers         54f0238b6bf101fc3ad3b34114cb
 github.com/docker/go                                d30aec9fd63c35133f8f79c3412ad91a3b08be06 # Contains a customized version of canonical/json and is used by Notary. The package is periodically rebased on current Go versions.
 github.com/docker/go-connections                    7395e3f8aa162843a74ed6d48e79627d9792ac55 # v0.4.0
 github.com/docker/go-events                         e31b211e4f1cd09aa76fe4ac244571fab96ae47f
-github.com/docker/go-metrics                        d466d4f6fd960e01820085bd7e1a24426ee7ef18
+github.com/docker/go-metrics                        b619b3592b65de4f087d9f16863a7e6ff905973c # v0.0.1
 github.com/docker/go-units                          519db1ee28dcc9fd2474ae59fca29a810482bfb1 # v0.4.0
 github.com/docker/swarmkit                          d6592ddefd8a5319aadff74c558b816b1a0b2590
 github.com/evanphx/json-patch                       72bf35d0ff611848c1dc9df0f976c81192392fa5 # v4.1.0
@@ -57,10 +58,10 @@ github.com/opencontainers/image-spec                d60099175f88c47cd379c4738d15
 github.com/opencontainers/runc                      ff819c7e9184c13b7c2607fe6c30ae19403a7aff # v1.0.0-rc92
 github.com/opentracing/opentracing-go               1361b9cd60be79c4c3a7fa9841b3c132e40066a7
 github.com/pkg/errors                               614d223910a179a466c1767a985424175c39b465 # v0.9.1
-github.com/prometheus/client_golang                 c5b7fccd204277076155f10851dad72b76a49317 # v0.8.0
-github.com/prometheus/client_model                  6f3806018612930941127f2a7c6c453ba2c527d2
-github.com/prometheus/common                        7600349dcfe1abd18d72d3a1770870d9800a7801
-github.com/prometheus/procfs                        7d6f385de8bea29190f15ba9931442a0eaef9af7
+github.com/prometheus/client_golang                 6edbbd9e560190e318cdc5b4d3e630b442858380 # v1.6.0
+github.com/prometheus/client_model                  7bc5445566f0fe75b15de23e6b93886e982d7bf9 # v0.2.0
+github.com/prometheus/common                        d978bcb1309602d68bb4ba69cf3f8ed900e07308 # v0.9.1
+github.com/prometheus/procfs                        46159f73e74d1cb8dc223deef9b2d049286f46b1 # v0.0.11
 github.com/russross/blackfriday/v2                  d3b5b032dc8e8927d31a5071b56e14c89f045135 # v2.0.1
 github.com/shurcooL/sanitized_anchor_name           7bfe4c7ecddb3666a94b053b422cdd8f5aaa3615 # v1.0.0
 github.com/sirupsen/logrus                          60c74ad9be0d874af0ab0daef6ab07c5c5911f0d # v1.6.0

vendor/github.com/cespare/xxhash/v2/LICENSE.txt

@@ -0,0 +1,22 @@
+Copyright (c) 2016 Caleb Spare
+
+MIT License
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

vendor/github.com/cespare/xxhash/v2/README.md

@@ -0,0 +1,67 @@
+# xxhash
+
+[![GoDoc](https://godoc.org/github.com/cespare/xxhash?status.svg)](https://godoc.org/github.com/cespare/xxhash)
+[![Build Status](https://travis-ci.org/cespare/xxhash.svg?branch=master)](https://travis-ci.org/cespare/xxhash)
+
+xxhash is a Go implementation of the 64-bit
+[xxHash](http://cyan4973.github.io/xxHash/) algorithm, XXH64. This is a
+high-quality hashing algorithm that is much faster than anything in the Go
+standard library.
+
+This package provides a straightforward API:
+
+```
+func Sum64(b []byte) uint64
+func Sum64String(s string) uint64
+type Digest struct{ ... }
+    func New() *Digest
+```
+
+The `Digest` type implements hash.Hash64. Its key methods are:
+
+```
+func (*Digest) Write([]byte) (int, error)
+func (*Digest) WriteString(string) (int, error)
+func (*Digest) Sum64() uint64
+```
+
+This implementation provides a fast pure-Go implementation and an even faster
+assembly implementation for amd64.
+
+## Compatibility
+
+This package is in a module and the latest code is in version 2 of the module.
+You need a version of Go with at least "minimal module compatibility" to use
+github.com/cespare/xxhash/v2:
+
+* 1.9.7+ for Go 1.9
+* 1.10.3+ for Go 1.10
+* Go 1.11 or later
+
+I recommend using the latest release of Go.
+
+## Benchmarks
+
+Here are some quick benchmarks comparing the pure-Go and assembly
+implementations of Sum64.
+
+| input size | purego | asm |
+| --- | --- | --- |
+| 5 B   |  979.66 MB/s |  1291.17 MB/s  |
+| 100 B | 7475.26 MB/s | 7973.40 MB/s  |
+| 4 KB  | 17573.46 MB/s | 17602.65 MB/s |
+| 10 MB | 17131.46 MB/s | 17142.16 MB/s |
+
+These numbers were generated on Ubuntu 18.04 with an Intel i7-8700K CPU using
+the following commands under Go 1.11.2:
+
+```
+$ go test -tags purego -benchtime 10s -bench '/xxhash,direct,bytes'
+$ go test -benchtime 10s -bench '/xxhash,direct,bytes'
+```
+
+## Projects using this package
+
+- [InfluxDB](https://github.com/influxdata/influxdb)
+- [Prometheus](https://github.com/prometheus/prometheus)
+- [FreeCache](https://github.com/coocood/freecache)

vendor/github.com/cespare/xxhash/v2/go.mod

@@ -0,0 +1,3 @@
+module github.com/cespare/xxhash/v2
+
+go 1.11

vendor/github.com/cespare/xxhash/v2/xxhash.go

@@ -0,0 +1,236 @@
+// Package xxhash implements the 64-bit variant of xxHash (XXH64) as described
+// at http://cyan4973.github.io/xxHash/.
+package xxhash
+
+import (
+	"encoding/binary"
+	"errors"
+	"math/bits"
+)
+
+const (
+	prime1 uint64 = 11400714785074694791
+	prime2 uint64 = 14029467366897019727
+	prime3 uint64 = 1609587929392839161
+	prime4 uint64 = 9650029242287828579
+	prime5 uint64 = 2870177450012600261
+)
+
+// NOTE(caleb): I'm using both consts and vars of the primes. Using consts where
+// possible in the Go code is worth a small (but measurable) performance boost
+// by avoiding some MOVQs. Vars are needed for the asm and also are useful for
+// convenience in the Go code in a few places where we need to intentionally
+// avoid constant arithmetic (e.g., v1 := prime1 + prime2 fails because the
+// result overflows a uint64).
+var (
+	prime1v = prime1
+	prime2v = prime2
+	prime3v = prime3
+	prime4v = prime4
+	prime5v = prime5
+)
+
+// Digest implements hash.Hash64.
+type Digest struct {
+	v1    uint64
+	v2    uint64
+	v3    uint64
+	v4    uint64
+	total uint64
+	mem   [32]byte
+	n     int // how much of mem is used
+}
+
+// New creates a new Digest that computes the 64-bit xxHash algorithm.
+func New() *Digest {
+	var d Digest
+	d.Reset()
+	return &d
+}
+
+// Reset clears the Digest's state so that it can be reused.
+func (d *Digest) Reset() {
+	d.v1 = prime1v + prime2
+	d.v2 = prime2
+	d.v3 = 0
+	d.v4 = -prime1v
+	d.total = 0
+	d.n = 0
+}
+
+// Size always returns 8 bytes.
+func (d *Digest) Size() int { return 8 }
+
+// BlockSize always returns 32 bytes.
+func (d *Digest) BlockSize() int { return 32 }
+
+// Write adds more data to d. It always returns len(b), nil.
+func (d *Digest) Write(b []byte) (n int, err error) {
+	n = len(b)
+	d.total += uint64(n)
+
+	if d.n+n < 32 {
+		// This new data doesn't even fill the current block.
+		copy(d.mem[d.n:], b)
+		d.n += n
+		return
+	}
+
+	if d.n > 0 {
+		// Finish off the partial block.
+		copy(d.mem[d.n:], b)
+		d.v1 = round(d.v1, u64(d.mem[0:8]))
+		d.v2 = round(d.v2, u64(d.mem[8:16]))
+		d.v3 = round(d.v3, u64(d.mem[16:24]))
+		d.v4 = round(d.v4, u64(d.mem[24:32]))
+		b = b[32-d.n:]
+		d.n = 0
+	}
+
+	if len(b) >= 32 {
+		// One or more full blocks left.
+		nw := writeBlocks(d, b)
+		b = b[nw:]
+	}
+
+	// Store any remaining partial block.
+	copy(d.mem[:], b)
+	d.n = len(b)
+
+	return
+}
+
+// Sum appends the current hash to b and returns the resulting slice.
+func (d *Digest) Sum(b []byte) []byte {
+	s := d.Sum64()
+	return append(
+		b,
+		byte(s>>56),
+		byte(s>>48),
+		byte(s>>40),
+		byte(s>>32),
+		byte(s>>24),
+		byte(s>>16),
+		byte(s>>8),
+		byte(s),
+	)
+}
+
+// Sum64 returns the current hash.
+func (d *Digest) Sum64() uint64 {
+	var h uint64
+
+	if d.total >= 32 {
+		v1, v2, v3, v4 := d.v1, d.v2, d.v3, d.v4
+		h = rol1(v1) + rol7(v2) + rol12(v3) + rol18(v4)
+		h = mergeRound(h, v1)
+		h = mergeRound(h, v2)
+		h = mergeRound(h, v3)
+		h = mergeRound(h, v4)
+	} else {
+		h = d.v3 + prime5
+	}
+
+	h += d.total
+
+	i, end := 0, d.n
+	for ; i+8 <= end; i += 8 {
+		k1 := round(0, u64(d.mem[i:i+8]))
+		h ^= k1
+		h = rol27(h)*prime1 + prime4
+	}
+	if i+4 <= end {
+		h ^= uint64(u32(d.mem[i:i+4])) * prime1
+		h = rol23(h)*prime2 + prime3
+		i += 4
+	}
+	for i < end {
+		h ^= uint64(d.mem[i]) * prime5
+		h = rol11(h) * prime1
+		i++
+	}
+
+	h ^= h >> 33
+	h *= prime2
+	h ^= h >> 29
+	h *= prime3
+	h ^= h >> 32
+
+	return h
+}
+
+const (
+	magic         = "xxh\x06"
+	marshaledSize = len(magic) + 8*5 + 32
+)
+
+// MarshalBinary implements the encoding.BinaryMarshaler interface.
+func (d *Digest) MarshalBinary() ([]byte, error) {
+	b := make([]byte, 0, marshaledSize)
+	b = append(b, magic...)
+	b = appendUint64(b, d.v1)
+	b = appendUint64(b, d.v2)
+	b = appendUint64(b, d.v3)
+	b = appendUint64(b, d.v4)
+	b = appendUint64(b, d.total)
+	b = append(b, d.mem[:d.n]...)
+	b = b[:len(b)+len(d.mem)-d.n]
+	return b, nil
+}
+
+// UnmarshalBinary implements the encoding.BinaryUnmarshaler interface.
+func (d *Digest) UnmarshalBinary(b []byte) error {
+	if len(b) < len(magic) || string(b[:len(magic)]) != magic {
+		return errors.New("xxhash: invalid hash state identifier")
+	}
+	if len(b) != marshaledSize {
+		return errors.New("xxhash: invalid hash state size")
+	}
+	b = b[len(magic):]
+	b, d.v1 = consumeUint64(b)
+	b, d.v2 = consumeUint64(b)
+	b, d.v3 = consumeUint64(b)
+	b, d.v4 = consumeUint64(b)
+	b, d.total = consumeUint64(b)
+	copy(d.mem[:], b)
+	b = b[len(d.mem):]
+	d.n = int(d.total % uint64(len(d.mem)))
+	return nil
+}
+
+func appendUint64(b []byte, x uint64) []byte {
+	var a [8]byte
+	binary.LittleEndian.PutUint64(a[:], x)
+	return append(b, a[:]...)
+}
+
+func consumeUint64(b []byte) ([]byte, uint64) {
+	x := u64(b)
+	return b[8:], x
+}
+
+func u64(b []byte) uint64 { return binary.LittleEndian.Uint64(b) }
+func u32(b []byte) uint32 { return binary.LittleEndian.Uint32(b) }
+
+func round(acc, input uint64) uint64 {
+	acc += input * prime2
+	acc = rol31(acc)
+	acc *= prime1
+	return acc
+}
+
+func mergeRound(acc, val uint64) uint64 {
+	val = round(0, val)
+	acc ^= val
+	acc = acc*prime1 + prime4
+	return acc
+}
+
+func rol1(x uint64) uint64  { return bits.RotateLeft64(x, 1) }
+func rol7(x uint64) uint64  { return bits.RotateLeft64(x, 7) }
+func rol11(x uint64) uint64 { return bits.RotateLeft64(x, 11) }
+func rol12(x uint64) uint64 { return bits.RotateLeft64(x, 12) }
+func rol18(x uint64) uint64 { return bits.RotateLeft64(x, 18) }
+func rol23(x uint64) uint64 { return bits.RotateLeft64(x, 23) }
+func rol27(x uint64) uint64 { return bits.RotateLeft64(x, 27) }
+func rol31(x uint64) uint64 { return bits.RotateLeft64(x, 31) }

vendor/github.com/cespare/xxhash/v2/xxhash_amd64.go

@@ -0,0 +1,13 @@
+// +build !appengine
+// +build gc
+// +build !purego
+
+package xxhash
+
+// Sum64 computes the 64-bit xxHash digest of b.
+//
+//go:noescape
+func Sum64(b []byte) uint64
+
+//go:noescape
+func writeBlocks(d *Digest, b []byte) int

vendor/github.com/cespare/xxhash/v2/xxhash_amd64.s

@@ -0,0 +1,215 @@
+// +build !appengine
+// +build gc
+// +build !purego
+
+#include "textflag.h"
+
+// Register allocation:
+// AX	h
+// CX	pointer to advance through b
+// DX	n
+// BX	loop end
+// R8	v1, k1
+// R9	v2
+// R10	v3
+// R11	v4
+// R12	tmp
+// R13	prime1v
+// R14	prime2v
+// R15	prime4v
+
+// round reads from and advances the buffer pointer in CX.
+// It assumes that R13 has prime1v and R14 has prime2v.
+#define round(r) \
+	MOVQ  (CX), R12 \
+	ADDQ  $8, CX    \
+	IMULQ R14, R12  \
+	ADDQ  R12, r    \
+	ROLQ  $31, r    \
+	IMULQ R13, r
+
+// mergeRound applies a merge round on the two registers acc and val.
+// It assumes that R13 has prime1v, R14 has prime2v, and R15 has prime4v.
+#define mergeRound(acc, val) \
+	IMULQ R14, val \
+	ROLQ  $31, val \
+	IMULQ R13, val \
+	XORQ  val, acc \
+	IMULQ R13, acc \
+	ADDQ  R15, acc
+
+// func Sum64(b []byte) uint64
+TEXT ·Sum64(SB), NOSPLIT, $0-32
+	// Load fixed primes.
+	MOVQ ·prime1v(SB), R13
+	MOVQ ·prime2v(SB), R14
+	MOVQ ·prime4v(SB), R15
+
+	// Load slice.
+	MOVQ b_base+0(FP), CX
+	MOVQ b_len+8(FP), DX
+	LEAQ (CX)(DX*1), BX
+
+	// The first loop limit will be len(b)-32.
+	SUBQ $32, BX
+
+	// Check whether we have at least one block.
+	CMPQ DX, $32
+	JLT  noBlocks
+
+	// Set up initial state (v1, v2, v3, v4).
+	MOVQ R13, R8
+	ADDQ R14, R8
+	MOVQ R14, R9
+	XORQ R10, R10
+	XORQ R11, R11
+	SUBQ R13, R11
+
+	// Loop until CX > BX.
+blockLoop:
+	round(R8)
+	round(R9)
+	round(R10)
+	round(R11)
+
+	CMPQ CX, BX
+	JLE  blockLoop
+
+	MOVQ R8, AX
+	ROLQ $1, AX
+	MOVQ R9, R12
+	ROLQ $7, R12
+	ADDQ R12, AX
+	MOVQ R10, R12
+	ROLQ $12, R12
+	ADDQ R12, AX
+	MOVQ R11, R12
+	ROLQ $18, R12
+	ADDQ R12, AX
+
+	mergeRound(AX, R8)
+	mergeRound(AX, R9)
+	mergeRound(AX, R10)
+	mergeRound(AX, R11)
+
+	JMP afterBlocks
+
+noBlocks:
+	MOVQ ·prime5v(SB), AX
+
+afterBlocks:
+	ADDQ DX, AX
+
+	// Right now BX has len(b)-32, and we want to loop until CX > len(b)-8.
+	ADDQ $24, BX
+
+	CMPQ CX, BX
+	JG   fourByte
+
+wordLoop:
+	// Calculate k1.
+	MOVQ  (CX), R8
+	ADDQ  $8, CX
+	IMULQ R14, R8
+	ROLQ  $31, R8
+	IMULQ R13, R8
+
+	XORQ  R8, AX
+	ROLQ  $27, AX
+	IMULQ R13, AX
+	ADDQ  R15, AX
+
+	CMPQ CX, BX
+	JLE  wordLoop
+
+fourByte:
+	ADDQ $4, BX
+	CMPQ CX, BX
+	JG   singles
+
+	MOVL  (CX), R8
+	ADDQ  $4, CX
+	IMULQ R13, R8
+	XORQ  R8, AX
+
+	ROLQ  $23, AX
+	IMULQ R14, AX
+	ADDQ  ·prime3v(SB), AX
+
+singles:
+	ADDQ $4, BX
+	CMPQ CX, BX
+	JGE  finalize
+
+singlesLoop:
+	MOVBQZX (CX), R12
+	ADDQ    $1, CX
+	IMULQ   ·prime5v(SB), R12
+	XORQ    R12, AX
+
+	ROLQ  $11, AX
+	IMULQ R13, AX
+
+	CMPQ CX, BX
+	JL   singlesLoop
+
+finalize:
+	MOVQ  AX, R12
+	SHRQ  $33, R12
+	XORQ  R12, AX
+	IMULQ R14, AX
+	MOVQ  AX, R12
+	SHRQ  $29, R12
+	XORQ  R12, AX
+	IMULQ ·prime3v(SB), AX
+	MOVQ  AX, R12
+	SHRQ  $32, R12
+	XORQ  R12, AX
+
+	MOVQ AX, ret+24(FP)
+	RET
+
+// writeBlocks uses the same registers as above except that it uses AX to store
+// the d pointer.
+
+// func writeBlocks(d *Digest, b []byte) int
+TEXT ·writeBlocks(SB), NOSPLIT, $0-40
+	// Load fixed primes needed for round.
+	MOVQ ·prime1v(SB), R13
+	MOVQ ·prime2v(SB), R14
+
+	// Load slice.
+	MOVQ b_base+8(FP), CX
+	MOVQ b_len+16(FP), DX
+	LEAQ (CX)(DX*1), BX
+	SUBQ $32, BX
+
+	// Load vN from d.
+	MOVQ d+0(FP), AX
+	MOVQ 0(AX), R8   // v1
+	MOVQ 8(AX), R9   // v2
+	MOVQ 16(AX), R10 // v3
+	MOVQ 24(AX), R11 // v4
+
+	// We don't need to check the loop condition here; this function is
+	// always called with at least one block of data to process.
+blockLoop:
+	round(R8)
+	round(R9)
+	round(R10)
+	round(R11)
+
+	CMPQ CX, BX
+	JLE  blockLoop
+
+	// Copy vN back to d.
+	MOVQ R8, 0(AX)
+	MOVQ R9, 8(AX)
+	MOVQ R10, 16(AX)
+	MOVQ R11, 24(AX)
+
+	// The number of bytes written is CX minus the old base pointer.
+	SUBQ b_base+8(FP), CX
+	MOVQ CX, ret+32(FP)
+
+	RET

vendor/github.com/cespare/xxhash/v2/xxhash_other.go

@@ -0,0 +1,76 @@
+// +build !amd64 appengine !gc purego
+
+package xxhash
+
+// Sum64 computes the 64-bit xxHash digest of b.
+func Sum64(b []byte) uint64 {
+	// A simpler version would be
+	//   d := New()
+	//   d.Write(b)
+	//   return d.Sum64()
+	// but this is faster, particularly for small inputs.
+
+	n := len(b)
+	var h uint64
+
+	if n >= 32 {
+		v1 := prime1v + prime2
+		v2 := prime2
+		v3 := uint64(0)
+		v4 := -prime1v
+		for len(b) >= 32 {
+			v1 = round(v1, u64(b[0:8:len(b)]))
+			v2 = round(v2, u64(b[8:16:len(b)]))
+			v3 = round(v3, u64(b[16:24:len(b)]))
+			v4 = round(v4, u64(b[24:32:len(b)]))
+			b = b[32:len(b):len(b)]
+		}
+		h = rol1(v1) + rol7(v2) + rol12(v3) + rol18(v4)
+		h = mergeRound(h, v1)
+		h = mergeRound(h, v2)
+		h = mergeRound(h, v3)
+		h = mergeRound(h, v4)
+	} else {
+		h = prime5
+	}
+
+	h += uint64(n)
+
+	i, end := 0, len(b)
+	for ; i+8 <= end; i += 8 {
+		k1 := round(0, u64(b[i:i+8:len(b)]))
+		h ^= k1
+		h = rol27(h)*prime1 + prime4
+	}
+	if i+4 <= end {
+		h ^= uint64(u32(b[i:i+4:len(b)])) * prime1
+		h = rol23(h)*prime2 + prime3
+		i += 4
+	}
+	for ; i < end; i++ {
+		h ^= uint64(b[i]) * prime5
+		h = rol11(h) * prime1
+	}
+
+	h ^= h >> 33
+	h *= prime2
+	h ^= h >> 29
+	h *= prime3
+	h ^= h >> 32
+
+	return h
+}
+
+func writeBlocks(d *Digest, b []byte) int {
+	v1, v2, v3, v4 := d.v1, d.v2, d.v3, d.v4
+	n := len(b)
+	for len(b) >= 32 {
+		v1 = round(v1, u64(b[0:8:len(b)]))
+		v2 = round(v2, u64(b[8:16:len(b)]))
+		v3 = round(v3, u64(b[16:24:len(b)]))
+		v4 = round(v4, u64(b[24:32:len(b)]))
+		b = b[32:len(b):len(b)]
+	}
+	d.v1, d.v2, d.v3, d.v4 = v1, v2, v3, v4
+	return n - len(b)
+}

vendor/github.com/cespare/xxhash/v2/xxhash_safe.go

@@ -0,0 +1,15 @@
+// +build appengine
+
+// This file contains the safe implementations of otherwise unsafe-using code.
+
+package xxhash
+
+// Sum64String computes the 64-bit xxHash digest of s.
+func Sum64String(s string) uint64 {
+	return Sum64([]byte(s))
+}
+
+// WriteString adds more data to d. It always returns len(s), nil.
+func (d *Digest) WriteString(s string) (n int, err error) {
+	return d.Write([]byte(s))
+}

vendor/github.com/cespare/xxhash/v2/xxhash_unsafe.go

@@ -0,0 +1,46 @@
+// +build !appengine
+
+// This file encapsulates usage of unsafe.
+// xxhash_safe.go contains the safe implementations.
+
+package xxhash
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+// Notes:
+//
+// See https://groups.google.com/d/msg/golang-nuts/dcjzJy-bSpw/tcZYBzQqAQAJ
+// for some discussion about these unsafe conversions.
+//
+// In the future it's possible that compiler optimizations will make these
+// unsafe operations unnecessary: https://golang.org/issue/2205.
+//
+// Both of these wrapper functions still incur function call overhead since they
+// will not be inlined. We could write Go/asm copies of Sum64 and Digest.Write
+// for strings to squeeze out a bit more speed. Mid-stack inlining should
+// eventually fix this.
+
+// Sum64String computes the 64-bit xxHash digest of s.
+// It may be faster than Sum64([]byte(s)) by avoiding a copy.
+func Sum64String(s string) uint64 {
+	var b []byte
+	bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	bh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
+	bh.Len = len(s)
+	bh.Cap = len(s)
+	return Sum64(b)
+}
+
+// WriteString adds more data to d. It always returns len(s), nil.
+// It may be faster than Write([]byte(s)) by avoiding a copy.
+func (d *Digest) WriteString(s string) (n int, err error) {
+	var b []byte
+	bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	bh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
+	bh.Len = len(s)
+	bh.Cap = len(s)
+	return d.Write(b)
+}

vendor/github.com/docker/go-metrics/README.md

@@ -68,9 +68,21 @@ If you need to use a unit but it is not defined in the package please open a PR
 
 Package documentation can be found [here](https://godoc.org/github.com/docker/go-metrics).
 
+## HTTP Metrics
+
+To instrument a http handler, you can wrap the code like this:
+
+```go
+namespace := metrics.NewNamespace("docker_distribution", "http", metrics.Labels{"handler": "your_http_handler_name"})
+httpMetrics := namespace.NewDefaultHttpMetrics()
+metrics.Register(namespace)
+instrumentedHandler = metrics.InstrumentHandler(httpMetrics, unInstrumentedHandler)
+```
+Note: The `handler` label must be provided when a new namespace is created.
+
 ## Additional Metrics
 
-Additional metrics are also defined here that are not avaliable in the prometheus client.
+Additional metrics are also defined here that are not available in the prometheus client.
 If you need a custom metrics and it is generic enough to be used by multiple projects, define it here.
 
 

vendor/github.com/docker/go-metrics/go.mod

@@ -0,0 +1,5 @@
+module github.com/docker/go-metrics
+
+go 1.11
+
+require github.com/prometheus/client_golang v1.1.0

vendor/github.com/docker/go-metrics/handler.go

@@ -4,10 +4,71 @@ import (
 	"net/http"
 
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+// HTTPHandlerOpts describes a set of configurable options of http metrics
+type HTTPHandlerOpts struct {
+	DurationBuckets     []float64
+	RequestSizeBuckets  []float64
+	ResponseSizeBuckets []float64
+}
+
+const (
+	InstrumentHandlerResponseSize = iota
+	InstrumentHandlerRequestSize
+	InstrumentHandlerDuration
+	InstrumentHandlerCounter
+	InstrumentHandlerInFlight
+)
+
+type HTTPMetric struct {
+	prometheus.Collector
+	handlerType int
+}
+
+var (
+	defaultDurationBuckets     = []float64{.005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10, 25, 60}
+	defaultRequestSizeBuckets  = prometheus.ExponentialBuckets(1024, 2, 22) //1K to 4G
+	defaultResponseSizeBuckets = defaultRequestSizeBuckets
 )
 
 // Handler returns the global http.Handler that provides the prometheus
-// metrics format on GET requests
+// metrics format on GET requests. This handler is no longer instrumented.
 func Handler() http.Handler {
-	return prometheus.Handler()
+	return promhttp.Handler()
+}
+
+func InstrumentHandler(metrics []*HTTPMetric, handler http.Handler) http.HandlerFunc {
+	return InstrumentHandlerFunc(metrics, handler.ServeHTTP)
+}
+
+func InstrumentHandlerFunc(metrics []*HTTPMetric, handlerFunc http.HandlerFunc) http.HandlerFunc {
+	var handler http.Handler
+	handler = http.HandlerFunc(handlerFunc)
+	for _, metric := range metrics {
+		switch metric.handlerType {
+		case InstrumentHandlerResponseSize:
+			if collector, ok := metric.Collector.(prometheus.ObserverVec); ok {
+				handler = promhttp.InstrumentHandlerResponseSize(collector, handler)
+			}
+		case InstrumentHandlerRequestSize:
+			if collector, ok := metric.Collector.(prometheus.ObserverVec); ok {
+				handler = promhttp.InstrumentHandlerRequestSize(collector, handler)
+			}
+		case InstrumentHandlerDuration:
+			if collector, ok := metric.Collector.(prometheus.ObserverVec); ok {
+				handler = promhttp.InstrumentHandlerDuration(collector, handler)
+			}
+		case InstrumentHandlerCounter:
+			if collector, ok := metric.Collector.(*prometheus.CounterVec); ok {
+				handler = promhttp.InstrumentHandlerCounter(collector, handler)
+			}
+		case InstrumentHandlerInFlight:
+			if collector, ok := metric.Collector.(prometheus.Gauge); ok {
+				handler = promhttp.InstrumentHandlerInFlight(collector, handler)
+			}
+		}
+	}
+	return handler.ServeHTTP
 }

vendor/github.com/docker/go-metrics/namespace.go

@@ -179,3 +179,137 @@ func makeName(name string, unit Unit) string {
 
 	return fmt.Sprintf("%s_%s", name, unit)
 }
+
+func (n *Namespace) NewDefaultHttpMetrics(handlerName string) []*HTTPMetric {
+	return n.NewHttpMetricsWithOpts(handlerName, HTTPHandlerOpts{
+		DurationBuckets:     defaultDurationBuckets,
+		RequestSizeBuckets:  defaultResponseSizeBuckets,
+		ResponseSizeBuckets: defaultResponseSizeBuckets,
+	})
+}
+
+func (n *Namespace) NewHttpMetrics(handlerName string, durationBuckets, requestSizeBuckets, responseSizeBuckets []float64) []*HTTPMetric {
+	return n.NewHttpMetricsWithOpts(handlerName, HTTPHandlerOpts{
+		DurationBuckets:     durationBuckets,
+		RequestSizeBuckets:  requestSizeBuckets,
+		ResponseSizeBuckets: responseSizeBuckets,
+	})
+}
+
+func (n *Namespace) NewHttpMetricsWithOpts(handlerName string, opts HTTPHandlerOpts) []*HTTPMetric {
+	var httpMetrics []*HTTPMetric
+	inFlightMetric := n.NewInFlightGaugeMetric(handlerName)
+	requestTotalMetric := n.NewRequestTotalMetric(handlerName)
+	requestDurationMetric := n.NewRequestDurationMetric(handlerName, opts.DurationBuckets)
+	requestSizeMetric := n.NewRequestSizeMetric(handlerName, opts.RequestSizeBuckets)
+	responseSizeMetric := n.NewResponseSizeMetric(handlerName, opts.ResponseSizeBuckets)
+	httpMetrics = append(httpMetrics, inFlightMetric, requestDurationMetric, requestTotalMetric, requestSizeMetric, responseSizeMetric)
+	return httpMetrics
+}
+
+func (n *Namespace) NewInFlightGaugeMetric(handlerName string) *HTTPMetric {
+	labels := prometheus.Labels(n.labels)
+	labels["handler"] = handlerName
+	metric := prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace:   n.name,
+		Subsystem:   n.subsystem,
+		Name:        "in_flight_requests",
+		Help:        "The in-flight HTTP requests",
+		ConstLabels: prometheus.Labels(labels),
+	})
+	httpMetric := &HTTPMetric{
+		Collector:   metric,
+		handlerType: InstrumentHandlerInFlight,
+	}
+	n.Add(httpMetric)
+	return httpMetric
+}
+
+func (n *Namespace) NewRequestTotalMetric(handlerName string) *HTTPMetric {
+	labels := prometheus.Labels(n.labels)
+	labels["handler"] = handlerName
+	metric := prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace:   n.name,
+			Subsystem:   n.subsystem,
+			Name:        "requests_total",
+			Help:        "Total number of HTTP requests made.",
+			ConstLabels: prometheus.Labels(labels),
+		},
+		[]string{"code", "method"},
+	)
+	httpMetric := &HTTPMetric{
+		Collector:   metric,
+		handlerType: InstrumentHandlerCounter,
+	}
+	n.Add(httpMetric)
+	return httpMetric
+}
+func (n *Namespace) NewRequestDurationMetric(handlerName string, buckets []float64) *HTTPMetric {
+	if len(buckets) == 0 {
+		panic("DurationBuckets must be provided")
+	}
+	labels := prometheus.Labels(n.labels)
+	labels["handler"] = handlerName
+	opts := prometheus.HistogramOpts{
+		Namespace:   n.name,
+		Subsystem:   n.subsystem,
+		Name:        "request_duration_seconds",
+		Help:        "The HTTP request latencies in seconds.",
+		Buckets:     buckets,
+		ConstLabels: prometheus.Labels(labels),
+	}
+	metric := prometheus.NewHistogramVec(opts, []string{"method"})
+	httpMetric := &HTTPMetric{
+		Collector:   metric,
+		handlerType: InstrumentHandlerDuration,
+	}
+	n.Add(httpMetric)
+	return httpMetric
+}
+
+func (n *Namespace) NewRequestSizeMetric(handlerName string, buckets []float64) *HTTPMetric {
+	if len(buckets) == 0 {
+		panic("RequestSizeBuckets must be provided")
+	}
+	labels := prometheus.Labels(n.labels)
+	labels["handler"] = handlerName
+	opts := prometheus.HistogramOpts{
+		Namespace:   n.name,
+		Subsystem:   n.subsystem,
+		Name:        "request_size_bytes",
+		Help:        "The HTTP request sizes in bytes.",
+		Buckets:     buckets,
+		ConstLabels: prometheus.Labels(labels),
+	}
+	metric := prometheus.NewHistogramVec(opts, []string{})
+	httpMetric := &HTTPMetric{
+		Collector:   metric,
+		handlerType: InstrumentHandlerRequestSize,
+	}
+	n.Add(httpMetric)
+	return httpMetric
+}
+
+func (n *Namespace) NewResponseSizeMetric(handlerName string, buckets []float64) *HTTPMetric {
+	if len(buckets) == 0 {
+		panic("ResponseSizeBuckets must be provided")
+	}
+	labels := prometheus.Labels(n.labels)
+	labels["handler"] = handlerName
+	opts := prometheus.HistogramOpts{
+		Namespace:   n.name,
+		Subsystem:   n.subsystem,
+		Name:        "response_size_bytes",
+		Help:        "The HTTP response sizes in bytes.",
+		Buckets:     buckets,
+		ConstLabels: prometheus.Labels(labels),
+	}
+	metrics := prometheus.NewHistogramVec(opts, []string{})
+	httpMetric := &HTTPMetric{
+		Collector:   metrics,
+		handlerType: InstrumentHandlerResponseSize,
+	}
+	n.Add(httpMetric)
+	return httpMetric
+}

vendor/github.com/docker/go-metrics/timer.go

@@ -28,15 +28,27 @@ type Timer interface {
 
 // LabeledTimer is a timer that must have label values populated before use.
 type LabeledTimer interface {
-	WithValues(labels ...string) Timer
+	WithValues(labels ...string) *labeledTimerObserver
 }
 
 type labeledTimer struct {
 	m *prometheus.HistogramVec
 }
 
-func (lt *labeledTimer) WithValues(labels ...string) Timer {
-	return &timer{m: lt.m.WithLabelValues(labels...)}
+type labeledTimerObserver struct {
+	m prometheus.Observer
+}
+
+func (lbo *labeledTimerObserver) Update(duration time.Duration) {
+	lbo.m.Observe(duration.Seconds())
+}
+
+func (lbo *labeledTimerObserver) UpdateSince(since time.Time) {
+	lbo.m.Observe(time.Since(since).Seconds())
+}
+
+func (lt *labeledTimer) WithValues(labels ...string) *labeledTimerObserver {
+	return &labeledTimerObserver{m: lt.m.WithLabelValues(labels...)}
 }
 
 func (lt *labeledTimer) Describe(c chan<- *prometheus.Desc) {
@@ -48,7 +60,7 @@ func (lt *labeledTimer) Collect(c chan<- prometheus.Metric) {
 }
 
 type timer struct {
-	m prometheus.Histogram
+	m prometheus.Observer
 }
 
 func (t *timer) Update(duration time.Duration) {
@@ -60,9 +72,14 @@ func (t *timer) UpdateSince(since time.Time) {
 }
 
 func (t *timer) Describe(c chan<- *prometheus.Desc) {
-	t.m.Describe(c)
+	c <- t.m.(prometheus.Metric).Desc()
 }
 
 func (t *timer) Collect(c chan<- prometheus.Metric) {
-	t.m.Collect(c)
+	// Are there any observers that don't implement Collector? It is really
+	// unclear what the point of the upstream change was, but we'll let this
+	// panic if we get an observer that doesn't implement collector. In this
+	// case, we should almost always see metricVec objects, so this should
+	// never panic.
+	t.m.(prometheus.Collector).Collect(c)
 }

vendor/github.com/prometheus/client_golang/README.md

@@ -1,12 +1,34 @@
 # Prometheus Go client library
 
 [![Build Status](https://travis-ci.org/prometheus/client_golang.svg?branch=master)](https://travis-ci.org/prometheus/client_golang)
+[![Go Report Card](https://goreportcard.com/badge/github.com/prometheus/client_golang)](https://goreportcard.com/report/github.com/prometheus/client_golang)
+[![go-doc](https://godoc.org/github.com/prometheus/client_golang?status.svg)](https://godoc.org/github.com/prometheus/client_golang)
 
 This is the [Go](http://golang.org) client library for
 [Prometheus](http://prometheus.io). It has two separate parts, one for
 instrumenting application code, and one for creating clients that talk to the
 Prometheus HTTP API.
 
+__This library requires Go1.9 or later.__ The minimum required patch releases for older Go versions are Go1.9.7 and Go1.10.3.
+
+## Important note about releases and stability
+
+This repository generally follows [Semantic
+Versioning](https://semver.org/). However, the API client in
+prometheus/client_golang/api/… is still considered experimental. Breaking
+changes of the API client will _not_ trigger a new major release. The same is
+true for selected other new features explicitly marked as **EXPERIMENTAL** in
+CHANGELOG.md.
+
+Features that require breaking changes in the stable parts of the repository
+are being batched up and tracked in the [v2
+milestone](https://github.com/prometheus/client_golang/milestone/2). The v2
+development happens in a [separate
+branch](https://github.com/prometheus/client_golang/tree/dev-v2) for the time
+being. v2 releases off that branch will happen once sufficient stability is
+reached. In view of the widespread use of this repository, v1 and v2 will
+coexist for a while to enable a convenient transition.
+
 ## Instrumenting applications
 
 [![code-coverage](http://gocover.io/_badge/github.com/prometheus/client_golang/prometheus)](http://gocover.io/github.com/prometheus/client_golang/prometheus) [![go-doc](https://godoc.org/github.com/prometheus/client_golang/prometheus?status.svg)](https://godoc.org/github.com/prometheus/client_golang/prometheus)
@@ -14,8 +36,8 @@ Prometheus HTTP API.
 The
 [`prometheus` directory](https://github.com/prometheus/client_golang/tree/master/prometheus)
 contains the instrumentation library. See the
-[best practices section](http://prometheus.io/docs/practices/naming/) of the
-Prometheus documentation to learn more about instrumenting applications.
+[guide](https://prometheus.io/docs/guides/go-application/) on the Prometheus
+website to learn more about instrumenting applications.
 
 The
 [`examples` directory](https://github.com/prometheus/client_golang/tree/master/examples)
@@ -23,13 +45,14 @@ contains simple examples of instrumented code.
 
 ## Client for the Prometheus HTTP API
 
-[![code-coverage](http://gocover.io/_badge/github.com/prometheus/client_golang/api/prometheus)](http://gocover.io/github.com/prometheus/client_golang/api/prometheus) [![go-doc](https://godoc.org/github.com/prometheus/client_golang/api/prometheus?status.svg)](https://godoc.org/github.com/prometheus/client_golang/api/prometheus)
+[![code-coverage](http://gocover.io/_badge/github.com/prometheus/client_golang/api/prometheus/v1)](http://gocover.io/github.com/prometheus/client_golang/api/prometheus/v1) [![go-doc](https://godoc.org/github.com/prometheus/client_golang/api/prometheus?status.svg)](https://godoc.org/github.com/prometheus/client_golang/api)
 
 The
 [`api/prometheus` directory](https://github.com/prometheus/client_golang/tree/master/api/prometheus)
 contains the client for the
 [Prometheus HTTP API](http://prometheus.io/docs/querying/api/). It allows you
-to write Go applications that query time series data from a Prometheus server.
+to write Go applications that query time series data from a Prometheus
+server. It is still in alpha stage.
 
 ## Where is `model`, `extraction`, and `text`?
 

vendor/github.com/prometheus/client_golang/go.mod

@@ -0,0 +1,18 @@
+module github.com/prometheus/client_golang
+
+require (
+	github.com/beorn7/perks v1.0.1
+	github.com/cespare/xxhash/v2 v2.1.1
+	github.com/golang/protobuf v1.4.0
+	github.com/json-iterator/go v1.1.9
+	github.com/kr/pretty v0.1.0 // indirect
+	github.com/prometheus/client_model v0.2.0
+	github.com/prometheus/common v0.9.1
+	github.com/prometheus/procfs v0.0.11
+	github.com/stretchr/testify v1.4.0 // indirect
+	golang.org/x/sys v0.0.0-20200420163511-1957bb5e6d1f
+	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
+	gopkg.in/yaml.v2 v2.2.5 // indirect
+)
+
+go 1.11

vendor/github.com/prometheus/client_golang/prometheus/build_info.go

@@ -0,0 +1,29 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build go1.12
+
+package prometheus
+
+import "runtime/debug"
+
+// readBuildInfo is a wrapper around debug.ReadBuildInfo for Go 1.12+.
+func readBuildInfo() (path, version, sum string) {
+	path, version, sum = "unknown", "unknown", "unknown"
+	if bi, ok := debug.ReadBuildInfo(); ok {
+		path = bi.Main.Path
+		version = bi.Main.Version
+		sum = bi.Main.Sum
+	}
+	return
+}

vendor/github.com/prometheus/client_golang/prometheus/build_info_pre_1.12.go

@@ -0,0 +1,22 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !go1.12
+
+package prometheus
+
+// readBuildInfo is a wrapper around debug.ReadBuildInfo for Go versions before
+// 1.12. Remove this whole file once the minimum supported Go version is 1.12.
+func readBuildInfo() (path, version, sum string) {
+	return "unknown", "unknown", "unknown"
+}

vendor/github.com/prometheus/client_golang/prometheus/collector.go

@@ -29,27 +29,72 @@ type Collector interface {
 	// collected by this Collector to the provided channel and returns once
 	// the last descriptor has been sent. The sent descriptors fulfill the
 	// consistency and uniqueness requirements described in the Desc
-	// documentation. (It is valid if one and the same Collector sends
-	// duplicate descriptors. Those duplicates are simply ignored. However,
-	// two different Collectors must not send duplicate descriptors.) This
-	// method idempotently sends the same descriptors throughout the
-	// lifetime of the Collector. If a Collector encounters an error while
-	// executing this method, it must send an invalid descriptor (created
-	// with NewInvalidDesc) to signal the error to the registry.
+	// documentation.
+	//
+	// It is valid if one and the same Collector sends duplicate
+	// descriptors. Those duplicates are simply ignored. However, two
+	// different Collectors must not send duplicate descriptors.
+	//
+	// Sending no descriptor at all marks the Collector as “unchecked”,
+	// i.e. no checks will be performed at registration time, and the
+	// Collector may yield any Metric it sees fit in its Collect method.
+	//
+	// This method idempotently sends the same descriptors throughout the
+	// lifetime of the Collector. It may be called concurrently and
+	// therefore must be implemented in a concurrency safe way.
+	//
+	// If a Collector encounters an error while executing this method, it
+	// must send an invalid descriptor (created with NewInvalidDesc) to
+	// signal the error to the registry.
 	Describe(chan<- *Desc)
 	// Collect is called by the Prometheus registry when collecting
 	// metrics. The implementation sends each collected metric via the
 	// provided channel and returns once the last metric has been sent. The
-	// descriptor of each sent metric is one of those returned by
-	// Describe. Returned metrics that share the same descriptor must differ
-	// in their variable label values. This method may be called
-	// concurrently and must therefore be implemented in a concurrency safe
-	// way. Blocking occurs at the expense of total performance of rendering
-	// all registered metrics. Ideally, Collector implementations support
-	// concurrent readers.
+	// descriptor of each sent metric is one of those returned by Describe
+	// (unless the Collector is unchecked, see above). Returned metrics that
+	// share the same descriptor must differ in their variable label
+	// values.
+	//
+	// This method may be called concurrently and must therefore be
+	// implemented in a concurrency safe way. Blocking occurs at the expense
+	// of total performance of rendering all registered metrics. Ideally,
+	// Collector implementations support concurrent readers.
 	Collect(chan<- Metric)
 }
 
+// DescribeByCollect is a helper to implement the Describe method of a custom
+// Collector. It collects the metrics from the provided Collector and sends
+// their descriptors to the provided channel.
+//
+// If a Collector collects the same metrics throughout its lifetime, its
+// Describe method can simply be implemented as:
+//
+//   func (c customCollector) Describe(ch chan<- *Desc) {
+//   	DescribeByCollect(c, ch)
+//   }
+//
+// However, this will not work if the metrics collected change dynamically over
+// the lifetime of the Collector in a way that their combined set of descriptors
+// changes as well. The shortcut implementation will then violate the contract
+// of the Describe method. If a Collector sometimes collects no metrics at all
+// (for example vectors like CounterVec, GaugeVec, etc., which only collect
+// metrics after a metric with a fully specified label set has been accessed),
+// it might even get registered as an unchecked Collector (cf. the Register
+// method of the Registerer interface). Hence, only use this shortcut
+// implementation of Describe if you are certain to fulfill the contract.
+//
+// The Collector example demonstrates a use of DescribeByCollect.
+func DescribeByCollect(c Collector, descs chan<- *Desc) {
+	metrics := make(chan Metric)
+	go func() {
+		c.Collect(metrics)
+		close(metrics)
+	}()
+	for m := range metrics {
+		descs <- m.Desc()
+	}
+}
+
 // selfCollector implements Collector for a single Metric so that the Metric
 // collects itself. Add it as an anonymous field to a struct that implements
 // Metric, and call init with the Metric itself as an argument.

vendor/github.com/prometheus/client_golang/prometheus/counter.go

@@ -15,6 +15,11 @@ package prometheus
 
 import (
 	"errors"
+	"math"
+	"sync/atomic"
+	"time"
+
+	dto "github.com/prometheus/client_model/go"
 )
 
 // Counter is a Metric that represents a single numerical value that only ever
@@ -30,26 +35,42 @@ type Counter interface {
 	Metric
 	Collector
 
-	// Set is used to set the Counter to an arbitrary value. It is only used
-	// if you have to transfer a value from an external counter into this
-	// Prometheus metric. Do not use it for regular handling of a
-	// Prometheus counter (as it can be used to break the contract of
-	// monotonically increasing values).
-	//
-	// Deprecated: Use NewConstMetric to create a counter for an external
-	// value. A Counter should never be set.
-	Set(float64)
-	// Inc increments the counter by 1.
+	// Inc increments the counter by 1. Use Add to increment it by arbitrary
+	// non-negative values.
 	Inc()
 	// Add adds the given value to the counter. It panics if the value is <
 	// 0.
 	Add(float64)
 }
 
+// ExemplarAdder is implemented by Counters that offer the option of adding a
+// value to the Counter together with an exemplar. Its AddWithExemplar method
+// works like the Add method of the Counter interface but also replaces the
+// currently saved exemplar (if any) with a new one, created from the provided
+// value, the current time as timestamp, and the provided labels. Empty Labels
+// will lead to a valid (label-less) exemplar. But if Labels is nil, the current
+// exemplar is left in place. AddWithExemplar panics if the value is < 0, if any
+// of the provided labels are invalid, or if the provided labels contain more
+// than 64 runes in total.
+type ExemplarAdder interface {
+	AddWithExemplar(value float64, exemplar Labels)
+}
+
 // CounterOpts is an alias for Opts. See there for doc comments.
 type CounterOpts Opts
 
 // NewCounter creates a new Counter based on the provided CounterOpts.
+//
+// The returned implementation also implements ExemplarAdder. It is safe to
+// perform the corresponding type assertion.
+//
+// The returned implementation tracks the counter value in two separate
+// variables, a float64 and a uint64. The latter is used to track calls of the
+// Inc method and calls of the Add method with a value that can be represented
+// as a uint64. This allows atomic increments of the counter with optimal
+// performance. (It is common to have an Inc call in very hot execution paths.)
+// Both internal tracking values are added up in the Write method. This has to
+// be taken into account when it comes to precision and overflow behavior.
 func NewCounter(opts CounterOpts) Counter {
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
@@ -57,20 +78,83 @@ func NewCounter(opts CounterOpts) Counter {
 		nil,
 		opts.ConstLabels,
 	)
-	result := &counter{value: value{desc: desc, valType: CounterValue, labelPairs: desc.constLabelPairs}}
+	result := &counter{desc: desc, labelPairs: desc.constLabelPairs, now: time.Now}
 	result.init(result) // Init self-collection.
 	return result
 }
 
 type counter struct {
-	value
+	// valBits contains the bits of the represented float64 value, while
+	// valInt stores values that are exact integers. Both have to go first
+	// in the struct to guarantee alignment for atomic operations.
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	valBits uint64
+	valInt  uint64
+
+	selfCollector
+	desc *Desc
+
+	labelPairs []*dto.LabelPair
+	exemplar   atomic.Value // Containing nil or a *dto.Exemplar.
+
+	now func() time.Time // To mock out time.Now() for testing.
+}
+
+func (c *counter) Desc() *Desc {
+	return c.desc
 }
 
 func (c *counter) Add(v float64) {
 	if v < 0 {
 		panic(errors.New("counter cannot decrease in value"))
 	}
-	c.value.Add(v)
+
+	ival := uint64(v)
+	if float64(ival) == v {
+		atomic.AddUint64(&c.valInt, ival)
+		return
+	}
+
+	for {
+		oldBits := atomic.LoadUint64(&c.valBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
+		if atomic.CompareAndSwapUint64(&c.valBits, oldBits, newBits) {
+			return
+		}
+	}
+}
+
+func (c *counter) AddWithExemplar(v float64, e Labels) {
+	c.Add(v)
+	c.updateExemplar(v, e)
+}
+
+func (c *counter) Inc() {
+	atomic.AddUint64(&c.valInt, 1)
+}
+
+func (c *counter) Write(out *dto.Metric) error {
+	fval := math.Float64frombits(atomic.LoadUint64(&c.valBits))
+	ival := atomic.LoadUint64(&c.valInt)
+	val := fval + float64(ival)
+
+	var exemplar *dto.Exemplar
+	if e := c.exemplar.Load(); e != nil {
+		exemplar = e.(*dto.Exemplar)
+	}
+
+	return populateMetric(CounterValue, val, c.labelPairs, exemplar, out)
+}
+
+func (c *counter) updateExemplar(v float64, l Labels) {
+	if l == nil {
+		return
+	}
+	e, err := newExemplar(v, c.now(), l)
+	if err != nil {
+		panic(err)
+	}
+	c.exemplar.Store(e)
 }
 
 // CounterVec is a Collector that bundles a set of Counters that all share the
@@ -78,16 +162,12 @@ func (c *counter) Add(v float64) {
 // if you want to count the same thing partitioned by various dimensions
 // (e.g. number of HTTP requests, partitioned by response code and
 // method). Create instances with NewCounterVec.
-//
-// CounterVec embeds MetricVec. See there for a full list of methods with
-// detailed documentation.
 type CounterVec struct {
-	*MetricVec
+	*metricVec
 }
 
 // NewCounterVec creates a new CounterVec based on the provided CounterOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
+// partitioned by the given label names.
 func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
@@ -96,34 +176,62 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 		opts.ConstLabels,
 	)
 	return &CounterVec{
-		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
-			result := &counter{value: value{
-				desc:       desc,
-				valType:    CounterValue,
-				labelPairs: makeLabelPairs(desc, lvs),
-			}}
+		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
+			if len(lvs) != len(desc.variableLabels) {
+				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, lvs))
+			}
+			result := &counter{desc: desc, labelPairs: makeLabelPairs(desc, lvs), now: time.Now}
 			result.init(result) // Init self-collection.
 			return result
 		}),
 	}
 }
 
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns a Counter and not a
-// Metric so that no type conversion is required.
-func (m *CounterVec) GetMetricWithLabelValues(lvs ...string) (Counter, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
+// GetMetricWithLabelValues returns the Counter for the given slice of label
+// values (same order as the VariableLabels in Desc). If that combination of
+// label values is accessed for the first time, a new Counter is created.
+//
+// It is possible to call this method without using the returned Counter to only
+// create the new Counter but leave it at its starting value 0. See also the
+// SummaryVec example.
+//
+// Keeping the Counter for later use is possible (and should be considered if
+// performance is critical), but keep in mind that Reset, DeleteLabelValues and
+// Delete can be used to delete the Counter from the CounterVec. In that case,
+// the Counter will still exist, but it will not be exported anymore, even if a
+// Counter with the same label values is created later.
+//
+// An error is returned if the number of label values is not the same as the
+// number of VariableLabels in Desc (minus any curried labels).
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
+// an alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
+// See also the GaugeVec example.
+func (v *CounterVec) GetMetricWithLabelValues(lvs ...string) (Counter, error) {
+	metric, err := v.metricVec.getMetricWithLabelValues(lvs...)
 	if metric != nil {
 		return metric.(Counter), err
 	}
 	return nil, err
 }
 
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns a Counter and not a Metric so that no
-// type conversion is required.
-func (m *CounterVec) GetMetricWith(labels Labels) (Counter, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
+// GetMetricWith returns the Counter for the given Labels map (the label names
+// must match those of the VariableLabels in Desc). If that label map is
+// accessed for the first time, a new Counter is created. Implications of
+// creating a Counter without using it and keeping the Counter for later use are
+// the same as for GetMetricWithLabelValues.
+//
+// An error is returned if the number and names of the Labels are inconsistent
+// with those of the VariableLabels in Desc (minus any curried labels).
+//
+// This method is used for the same purpose as
+// GetMetricWithLabelValues(...string). See there for pros and cons of the two
+// methods.
+func (v *CounterVec) GetMetricWith(labels Labels) (Counter, error) {
+	metric, err := v.metricVec.getMetricWith(labels)
 	if metric != nil {
 		return metric.(Counter), err
 	}
@@ -131,18 +239,57 @@ func (m *CounterVec) GetMetricWith(labels Labels) (Counter, error) {
 }
 
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
+// GetMetricWithLabelValues would have returned an error. Not returning an
+// error allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Add(42)
-func (m *CounterVec) WithLabelValues(lvs ...string) Counter {
-	return m.MetricVec.WithLabelValues(lvs...).(Counter)
+func (v *CounterVec) WithLabelValues(lvs ...string) Counter {
+	c, err := v.GetMetricWithLabelValues(lvs...)
+	if err != nil {
+		panic(err)
+	}
+	return c
 }
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
-func (m *CounterVec) With(labels Labels) Counter {
-	return m.MetricVec.With(labels).(Counter)
+// returned an error. Not returning an error allows shortcuts like
+//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Add(42)
+func (v *CounterVec) With(labels Labels) Counter {
+	c, err := v.GetMetricWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return c
+}
+
+// CurryWith returns a vector curried with the provided labels, i.e. the
+// returned vector has those labels pre-set for all labeled operations performed
+// on it. The cardinality of the curried vector is reduced accordingly. The
+// order of the remaining labels stays the same (just with the curried labels
+// taken out of the sequence – which is relevant for the
+// (GetMetric)WithLabelValues methods). It is possible to curry a curried
+// vector, but only with labels not yet used for currying before.
+//
+// The metrics contained in the CounterVec are shared between the curried and
+// uncurried vectors. They are just accessed differently. Curried and uncurried
+// vectors behave identically in terms of collection. Only one must be
+// registered with a given registry (usually the uncurried version). The Reset
+// method deletes all metrics, even if called on a curried vector.
+func (v *CounterVec) CurryWith(labels Labels) (*CounterVec, error) {
+	vec, err := v.curryWith(labels)
+	if vec != nil {
+		return &CounterVec{vec}, err
+	}
+	return nil, err
+}
+
+// MustCurryWith works as CurryWith but panics where CurryWith would have
+// returned an error.
+func (v *CounterVec) MustCurryWith(labels Labels) *CounterVec {
+	vec, err := v.CurryWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return vec
 }
 
 // CounterFunc is a Counter whose value is determined at collect time by calling a
@@ -162,6 +309,8 @@ type CounterFunc interface {
 // provided function must be concurrency-safe. The function should also honor
 // the contract for a Counter (values only go up, not down), but compliance will
 // not be checked.
+//
+// Check out the ExampleGaugeFunc examples for the similar GaugeFunc.
 func NewCounterFunc(opts CounterOpts, function func() float64) CounterFunc {
 	return newValueFunc(NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),

vendor/github.com/prometheus/client_golang/prometheus/desc.go

@@ -16,33 +16,16 @@ package prometheus
 import (
 	"errors"
 	"fmt"
-	"regexp"
 	"sort"
 	"strings"
 
+	"github.com/cespare/xxhash/v2"
 	"github.com/golang/protobuf/proto"
+	"github.com/prometheus/common/model"
 
 	dto "github.com/prometheus/client_model/go"
 )
 
-var (
-	metricNameRE = regexp.MustCompile(`^[a-zA-Z_][a-zA-Z0-9_:]*$`)
-	labelNameRE  = regexp.MustCompile("^[a-zA-Z_][a-zA-Z0-9_]*$")
-)
-
-// reservedLabelPrefix is a prefix which is not legal in user-supplied
-// label names.
-const reservedLabelPrefix = "__"
-
-// Labels represents a collection of label name -> value mappings. This type is
-// commonly used with the With(Labels) and GetMetricWith(Labels) methods of
-// metric vector Collectors, e.g.:
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
-//
-// The other use-case is the specification of constant label pairs in Opts or to
-// create a Desc.
-type Labels map[string]string
-
 // Desc is the descriptor used by every Prometheus Metric. It is essentially
 // the immutable meta-data of a Metric. The normal Metric implementations
 // included in this package manage their Desc under the hood. Users only have to
@@ -78,32 +61,27 @@ type Desc struct {
 	// Help string. Each Desc with the same fqName must have the same
 	// dimHash.
 	dimHash uint64
-	// err is an error that occured during construction. It is reported on
+	// err is an error that occurred during construction. It is reported on
 	// registration time.
 	err error
 }
 
 // NewDesc allocates and initializes a new Desc. Errors are recorded in the Desc
 // and will be reported on registration time. variableLabels and constLabels can
-// be nil if no such labels should be set. fqName and help must not be empty.
+// be nil if no such labels should be set. fqName must not be empty.
 //
 // variableLabels only contain the label names. Their label values are variable
 // and therefore not part of the Desc. (They are managed within the Metric.)
 //
 // For constLabels, the label values are constant. Therefore, they are fully
-// specified in the Desc. See the Opts documentation for the implications of
-// constant labels.
+// specified in the Desc. See the Collector example for a usage pattern.
 func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *Desc {
 	d := &Desc{
 		fqName:         fqName,
 		help:           help,
 		variableLabels: variableLabels,
 	}
-	if help == "" {
-		d.err = errors.New("empty help string")
-		return d
-	}
-	if !metricNameRE.MatchString(fqName) {
+	if !model.IsValidMetricName(model.LabelValue(fqName)) {
 		d.err = fmt.Errorf("%q is not a valid metric name", fqName)
 		return d
 	}
@@ -116,7 +94,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 	// First add only the const label names and sort them...
 	for labelName := range constLabels {
 		if !checkLabelName(labelName) {
-			d.err = fmt.Errorf("%q is not a valid label name", labelName)
+			d.err = fmt.Errorf("%q is not a valid label name for metric %q", labelName, fqName)
 			return d
 		}
 		labelNames = append(labelNames, labelName)
@@ -127,12 +105,18 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 	for _, labelName := range labelNames {
 		labelValues = append(labelValues, constLabels[labelName])
 	}
+	// Validate the const label values. They can't have a wrong cardinality, so
+	// use in len(labelValues) as expectedNumberOfValues.
+	if err := validateLabelValues(labelValues, len(labelValues)); err != nil {
+		d.err = err
+		return d
+	}
 	// Now add the variable label names, but prefix them with something that
 	// cannot be in a regular label name. That prevents matching the label
 	// dimension with a different mix between preset and variable labels.
 	for _, labelName := range variableLabels {
 		if !checkLabelName(labelName) {
-			d.err = fmt.Errorf("%q is not a valid label name", labelName)
+			d.err = fmt.Errorf("%q is not a valid label name for metric %q", labelName, fqName)
 			return d
 		}
 		labelNames = append(labelNames, "$"+labelName)
@@ -142,24 +126,25 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 		d.err = errors.New("duplicate label names")
 		return d
 	}
-	vh := hashNew()
+
+	xxh := xxhash.New()
 	for _, val := range labelValues {
-		vh = hashAdd(vh, val)
-		vh = hashAddByte(vh, separatorByte)
+		xxh.WriteString(val)
+		xxh.Write(separatorByteSlice)
 	}
-	d.id = vh
+	d.id = xxh.Sum64()
 	// Sort labelNames so that order doesn't matter for the hash.
 	sort.Strings(labelNames)
 	// Now hash together (in this order) the help string and the sorted
 	// label names.
-	lh := hashNew()
-	lh = hashAdd(lh, help)
-	lh = hashAddByte(lh, separatorByte)
+	xxh.Reset()
+	xxh.WriteString(help)
+	xxh.Write(separatorByteSlice)
 	for _, labelName := range labelNames {
-		lh = hashAdd(lh, labelName)
-		lh = hashAddByte(lh, separatorByte)
+		xxh.WriteString(labelName)
+		xxh.Write(separatorByteSlice)
 	}
-	d.dimHash = lh
+	d.dimHash = xxh.Sum64()
 
 	d.constLabelPairs = make([]*dto.LabelPair, 0, len(constLabels))
 	for n, v := range constLabels {
@@ -168,7 +153,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 			Value: proto.String(v),
 		})
 	}
-	sort.Sort(LabelPairSorter(d.constLabelPairs))
+	sort.Sort(labelPairSorter(d.constLabelPairs))
 	return d
 }
 
@@ -198,8 +183,3 @@ func (d *Desc) String() string {
 		d.variableLabels,
 	)
 }
-
-func checkLabelName(l string) bool {
-	return labelNameRE.MatchString(l) &&
-		!strings.HasPrefix(l, reservedLabelPrefix)
-}

vendor/github.com/prometheus/client_golang/prometheus/doc.go

@@ -11,13 +11,15 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package prometheus provides metrics primitives to instrument code for
-// monitoring. It also offers a registry for metrics. Sub-packages allow to
-// expose the registered metrics via HTTP (package promhttp) or push them to a
-// Pushgateway (package push).
+// Package prometheus is the core instrumentation package. It provides metrics
+// primitives to instrument code for monitoring. It also offers a registry for
+// metrics. Sub-packages allow to expose the registered metrics via HTTP
+// (package promhttp) or push them to a Pushgateway (package push). There is
+// also a sub-package promauto, which provides metrics constructors with
+// automatic registration.
 //
 // All exported functions and methods are safe to be used concurrently unless
-//specified otherwise.
+// specified otherwise.
 //
 // A Basic Example
 //
@@ -26,6 +28,7 @@
 //    package main
 //
 //    import (
+//    	"log"
 //    	"net/http"
 //
 //    	"github.com/prometheus/client_golang/prometheus"
@@ -59,7 +62,7 @@
 //    	// The Handler function provides a default handler to expose metrics
 //    	// via an HTTP server. "/metrics" is the usual endpoint for that.
 //    	http.Handle("/metrics", promhttp.Handler())
-//    	http.ListenAndServe(":8080", nil)
+//    	log.Fatal(http.ListenAndServe(":8080", nil))
 //    }
 //
 //
@@ -69,34 +72,33 @@
 // Metrics
 //
 // The number of exported identifiers in this package might appear a bit
-// overwhelming. Hovever, in addition to the basic plumbing shown in the example
+// overwhelming. However, in addition to the basic plumbing shown in the example
 // above, you only need to understand the different metric types and their
-// vector versions for basic usage.
+// vector versions for basic usage. Furthermore, if you are not concerned with
+// fine-grained control of when and how to register metrics with the registry,
+// have a look at the promauto package, which will effectively allow you to
+// ignore registration altogether in simple cases.
 //
 // Above, you have already touched the Counter and the Gauge. There are two more
 // advanced metric types: the Summary and Histogram. A more thorough description
 // of those four metric types can be found in the Prometheus docs:
 // https://prometheus.io/docs/concepts/metric_types/
 //
-// A fifth "type" of metric is Untyped. It behaves like a Gauge, but signals the
-// Prometheus server not to assume anything about its type.
-//
-// In addition to the fundamental metric types Gauge, Counter, Summary,
-// Histogram, and Untyped, a very important part of the Prometheus data model is
-// the partitioning of samples along dimensions called labels, which results in
+// In addition to the fundamental metric types Gauge, Counter, Summary, and
+// Histogram, a very important part of the Prometheus data model is the
+// partitioning of samples along dimensions called labels, which results in
 // metric vectors. The fundamental types are GaugeVec, CounterVec, SummaryVec,
-// HistogramVec, and UntypedVec.
+// and HistogramVec.
 //
 // While only the fundamental metric types implement the Metric interface, both
 // the metrics and their vector versions implement the Collector interface. A
 // Collector manages the collection of a number of Metrics, but for convenience,
-// a Metric can also “collect itself”. Note that Gauge, Counter, Summary,
-// Histogram, and Untyped are interfaces themselves while GaugeVec, CounterVec,
-// SummaryVec, HistogramVec, and UntypedVec are not.
+// a Metric can also “collect itself”. Note that Gauge, Counter, Summary, and
+// Histogram are interfaces themselves while GaugeVec, CounterVec, SummaryVec,
+// and HistogramVec are not.
 //
 // To create instances of Metrics and their vector versions, you need a suitable
-// …Opts struct, i.e. GaugeOpts, CounterOpts, SummaryOpts,
-// HistogramOpts, or UntypedOpts.
+// …Opts struct, i.e. GaugeOpts, CounterOpts, SummaryOpts, or HistogramOpts.
 //
 // Custom Collectors and constant Metrics
 //
@@ -112,10 +114,23 @@
 // existing numbers into Prometheus Metrics during collection. An own
 // implementation of the Collector interface is perfect for that. You can create
 // Metric instances “on the fly” using NewConstMetric, NewConstHistogram, and
-// NewConstSummary (and their respective Must… versions). That will happen in
-// the Collect method. The Describe method has to return separate Desc
-// instances, representative of the “throw-away” metrics to be created
-// later. NewDesc comes in handy to create those Desc instances.
+// NewConstSummary (and their respective Must… versions). NewConstMetric is used
+// for all metric types with just a float64 as their value: Counter, Gauge, and
+// a special “type” called Untyped. Use the latter if you are not sure if the
+// mirrored metric is a Counter or a Gauge. Creation of the Metric instance
+// happens in the Collect method. The Describe method has to return separate
+// Desc instances, representative of the “throw-away” metrics to be created
+// later.  NewDesc comes in handy to create those Desc instances. Alternatively,
+// you could return no Desc at all, which will mark the Collector “unchecked”.
+// No checks are performed at registration time, but metric consistency will
+// still be ensured at scrape time, i.e. any inconsistencies will lead to scrape
+// errors. Thus, with unchecked Collectors, the responsibility to not collect
+// metrics that lead to inconsistencies in the total scrape result lies with the
+// implementer of the Collector. While this is not a desirable state, it is
+// sometimes necessary. The typical use case is a situation where the exact
+// metrics to be returned by a Collector cannot be predicted at registration
+// time, but the implementer has sufficient knowledge of the whole system to
+// guarantee metric consistency.
 //
 // The Collector example illustrates the use case. You can also look at the
 // source code of the processCollector (mirroring process metrics), the
@@ -129,34 +144,34 @@
 // Advanced Uses of the Registry
 //
 // While MustRegister is the by far most common way of registering a Collector,
-// sometimes you might want to handle the errors the registration might
-// cause. As suggested by the name, MustRegister panics if an error occurs. With
-// the Register function, the error is returned and can be handled.
+// sometimes you might want to handle the errors the registration might cause.
+// As suggested by the name, MustRegister panics if an error occurs. With the
+// Register function, the error is returned and can be handled.
 //
 // An error is returned if the registered Collector is incompatible or
 // inconsistent with already registered metrics. The registry aims for
-// consistency of the collected metrics according to the Prometheus data
-// model. Inconsistencies are ideally detected at registration time, not at
-// collect time. The former will usually be detected at start-up time of a
-// program, while the latter will only happen at scrape time, possibly not even
-// on the first scrape if the inconsistency only becomes relevant later. That is
-// the main reason why a Collector and a Metric have to describe themselves to
-// the registry.
+// consistency of the collected metrics according to the Prometheus data model.
+// Inconsistencies are ideally detected at registration time, not at collect
+// time. The former will usually be detected at start-up time of a program,
+// while the latter will only happen at scrape time, possibly not even on the
+// first scrape if the inconsistency only becomes relevant later. That is the
+// main reason why a Collector and a Metric have to describe themselves to the
+// registry.
 //
 // So far, everything we did operated on the so-called default registry, as it
-// can be found in the global DefaultRegistry variable. With NewRegistry, you
+// can be found in the global DefaultRegisterer variable. With NewRegistry, you
 // can create a custom registry, or you can even implement the Registerer or
-// Gatherer interfaces yourself. The methods Register and Unregister work in
-// the same way on a custom registry as the global functions Register and
-// Unregister on the default registry.
+// Gatherer interfaces yourself. The methods Register and Unregister work in the
+// same way on a custom registry as the global functions Register and Unregister
+// on the default registry.
 //
-// There are a number of uses for custom registries: You can use registries
-// with special properties, see NewPedanticRegistry. You can avoid global state,
-// as it is imposed by the DefaultRegistry. You can use multiple registries at
-// the same time to expose different metrics in different ways. You can use
+// There are a number of uses for custom registries: You can use registries with
+// special properties, see NewPedanticRegistry. You can avoid global state, as
+// it is imposed by the DefaultRegisterer. You can use multiple registries at
+// the same time to expose different metrics in different ways.  You can use
 // separate registries for testing purposes.
 //
-// Also note that the DefaultRegistry comes registered with a Collector for Go
+// Also note that the DefaultRegisterer comes registered with a Collector for Go
 // runtime metrics (via NewGoCollector) and a Collector for process metrics (via
 // NewProcessCollector). With a custom registry, you are in control and decide
 // yourself about the Collectors to register.
@@ -166,16 +181,19 @@
 // The Registry implements the Gatherer interface. The caller of the Gather
 // method can then expose the gathered metrics in some way. Usually, the metrics
 // are served via HTTP on the /metrics endpoint. That's happening in the example
-// above. The tools to expose metrics via HTTP are in the promhttp
-// sub-package. (The top-level functions in the prometheus package are
-// deprecated.)
+// above. The tools to expose metrics via HTTP are in the promhttp sub-package.
 //
 // Pushing to the Pushgateway
 //
 // Function for pushing to the Pushgateway can be found in the push sub-package.
 //
+// Graphite Bridge
+//
+// Functions and examples to push metrics from a Gatherer to Graphite can be
+// found in the graphite sub-package.
+//
 // Other Means of Exposition
 //
-// More ways of exposing metrics can easily be added. Sending metrics to
-// Graphite would be an example that will soon be implemented.
+// More ways of exposing metrics can easily be added by following the approaches
+// of the existing implementations.
 package prometheus

vendor/github.com/prometheus/client_golang/prometheus/fnv.go

@@ -1,3 +1,16 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package prometheus
 
 // Inline and byte-free variant of hash/fnv's fnv64a.

vendor/github.com/prometheus/client_golang/prometheus/gauge.go

@@ -13,6 +13,14 @@
 
 package prometheus
 
+import (
+	"math"
+	"sync/atomic"
+	"time"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
 // Gauge is a Metric that represents a single numerical value that can
 // arbitrarily go up and down.
 //
@@ -27,29 +35,95 @@ type Gauge interface {
 
 	// Set sets the Gauge to an arbitrary value.
 	Set(float64)
-	// Inc increments the Gauge by 1.
+	// Inc increments the Gauge by 1. Use Add to increment it by arbitrary
+	// values.
 	Inc()
-	// Dec decrements the Gauge by 1.
+	// Dec decrements the Gauge by 1. Use Sub to decrement it by arbitrary
+	// values.
 	Dec()
-	// Add adds the given value to the Gauge. (The value can be
-	// negative, resulting in a decrease of the Gauge.)
+	// Add adds the given value to the Gauge. (The value can be negative,
+	// resulting in a decrease of the Gauge.)
 	Add(float64)
 	// Sub subtracts the given value from the Gauge. (The value can be
 	// negative, resulting in an increase of the Gauge.)
 	Sub(float64)
+
+	// SetToCurrentTime sets the Gauge to the current Unix time in seconds.
+	SetToCurrentTime()
 }
 
 // GaugeOpts is an alias for Opts. See there for doc comments.
 type GaugeOpts Opts
 
 // NewGauge creates a new Gauge based on the provided GaugeOpts.
+//
+// The returned implementation is optimized for a fast Set method. If you have a
+// choice for managing the value of a Gauge via Set vs. Inc/Dec/Add/Sub, pick
+// the former. For example, the Inc method of the returned Gauge is slower than
+// the Inc method of a Counter returned by NewCounter. This matches the typical
+// scenarios for Gauges and Counters, where the former tends to be Set-heavy and
+// the latter Inc-heavy.
 func NewGauge(opts GaugeOpts) Gauge {
-	return newValue(NewDesc(
+	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
 		nil,
 		opts.ConstLabels,
-	), GaugeValue, 0)
+	)
+	result := &gauge{desc: desc, labelPairs: desc.constLabelPairs}
+	result.init(result) // Init self-collection.
+	return result
+}
+
+type gauge struct {
+	// valBits contains the bits of the represented float64 value. It has
+	// to go first in the struct to guarantee alignment for atomic
+	// operations.  http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	valBits uint64
+
+	selfCollector
+
+	desc       *Desc
+	labelPairs []*dto.LabelPair
+}
+
+func (g *gauge) Desc() *Desc {
+	return g.desc
+}
+
+func (g *gauge) Set(val float64) {
+	atomic.StoreUint64(&g.valBits, math.Float64bits(val))
+}
+
+func (g *gauge) SetToCurrentTime() {
+	g.Set(float64(time.Now().UnixNano()) / 1e9)
+}
+
+func (g *gauge) Inc() {
+	g.Add(1)
+}
+
+func (g *gauge) Dec() {
+	g.Add(-1)
+}
+
+func (g *gauge) Add(val float64) {
+	for {
+		oldBits := atomic.LoadUint64(&g.valBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + val)
+		if atomic.CompareAndSwapUint64(&g.valBits, oldBits, newBits) {
+			return
+		}
+	}
+}
+
+func (g *gauge) Sub(val float64) {
+	g.Add(val * -1)
+}
+
+func (g *gauge) Write(out *dto.Metric) error {
+	val := math.Float64frombits(atomic.LoadUint64(&g.valBits))
+	return populateMetric(GaugeValue, val, g.labelPairs, nil, out)
 }
 
 // GaugeVec is a Collector that bundles a set of Gauges that all share the same
@@ -58,12 +132,11 @@ func NewGauge(opts GaugeOpts) Gauge {
 // (e.g. number of operations queued, partitioned by user and operation
 // type). Create instances with NewGaugeVec.
 type GaugeVec struct {
-	*MetricVec
+	*metricVec
 }
 
 // NewGaugeVec creates a new GaugeVec based on the provided GaugeOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
+// partitioned by the given label names.
 func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec {
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
@@ -72,28 +145,62 @@ func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec {
 		opts.ConstLabels,
 	)
 	return &GaugeVec{
-		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
-			return newValue(desc, GaugeValue, 0, lvs...)
+		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
+			if len(lvs) != len(desc.variableLabels) {
+				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, lvs))
+			}
+			result := &gauge{desc: desc, labelPairs: makeLabelPairs(desc, lvs)}
+			result.init(result) // Init self-collection.
+			return result
 		}),
 	}
 }
 
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns a Gauge and not a
-// Metric so that no type conversion is required.
-func (m *GaugeVec) GetMetricWithLabelValues(lvs ...string) (Gauge, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
+// GetMetricWithLabelValues returns the Gauge for the given slice of label
+// values (same order as the VariableLabels in Desc). If that combination of
+// label values is accessed for the first time, a new Gauge is created.
+//
+// It is possible to call this method without using the returned Gauge to only
+// create the new Gauge but leave it at its starting value 0. See also the
+// SummaryVec example.
+//
+// Keeping the Gauge for later use is possible (and should be considered if
+// performance is critical), but keep in mind that Reset, DeleteLabelValues and
+// Delete can be used to delete the Gauge from the GaugeVec. In that case, the
+// Gauge will still exist, but it will not be exported anymore, even if a
+// Gauge with the same label values is created later. See also the CounterVec
+// example.
+//
+// An error is returned if the number of label values is not the same as the
+// number of VariableLabels in Desc (minus any curried labels).
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
+// an alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
+func (v *GaugeVec) GetMetricWithLabelValues(lvs ...string) (Gauge, error) {
+	metric, err := v.metricVec.getMetricWithLabelValues(lvs...)
 	if metric != nil {
 		return metric.(Gauge), err
 	}
 	return nil, err
 }
 
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns a Gauge and not a Metric so that no
-// type conversion is required.
-func (m *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
+// GetMetricWith returns the Gauge for the given Labels map (the label names
+// must match those of the VariableLabels in Desc). If that label map is
+// accessed for the first time, a new Gauge is created. Implications of
+// creating a Gauge without using it and keeping the Gauge for later use are
+// the same as for GetMetricWithLabelValues.
+//
+// An error is returned if the number and names of the Labels are inconsistent
+// with those of the VariableLabels in Desc (minus any curried labels).
+//
+// This method is used for the same purpose as
+// GetMetricWithLabelValues(...string). See there for pros and cons of the two
+// methods.
+func (v *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) {
+	metric, err := v.metricVec.getMetricWith(labels)
 	if metric != nil {
 		return metric.(Gauge), err
 	}
@@ -101,18 +208,57 @@ func (m *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) {
 }
 
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
+// GetMetricWithLabelValues would have returned an error. Not returning an
+// error allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Add(42)
-func (m *GaugeVec) WithLabelValues(lvs ...string) Gauge {
-	return m.MetricVec.WithLabelValues(lvs...).(Gauge)
+func (v *GaugeVec) WithLabelValues(lvs ...string) Gauge {
+	g, err := v.GetMetricWithLabelValues(lvs...)
+	if err != nil {
+		panic(err)
+	}
+	return g
 }
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
-func (m *GaugeVec) With(labels Labels) Gauge {
-	return m.MetricVec.With(labels).(Gauge)
+// returned an error. Not returning an error allows shortcuts like
+//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Add(42)
+func (v *GaugeVec) With(labels Labels) Gauge {
+	g, err := v.GetMetricWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return g
+}
+
+// CurryWith returns a vector curried with the provided labels, i.e. the
+// returned vector has those labels pre-set for all labeled operations performed
+// on it. The cardinality of the curried vector is reduced accordingly. The
+// order of the remaining labels stays the same (just with the curried labels
+// taken out of the sequence – which is relevant for the
+// (GetMetric)WithLabelValues methods). It is possible to curry a curried
+// vector, but only with labels not yet used for currying before.
+//
+// The metrics contained in the GaugeVec are shared between the curried and
+// uncurried vectors. They are just accessed differently. Curried and uncurried
+// vectors behave identically in terms of collection. Only one must be
+// registered with a given registry (usually the uncurried version). The Reset
+// method deletes all metrics, even if called on a curried vector.
+func (v *GaugeVec) CurryWith(labels Labels) (*GaugeVec, error) {
+	vec, err := v.curryWith(labels)
+	if vec != nil {
+		return &GaugeVec{vec}, err
+	}
+	return nil, err
+}
+
+// MustCurryWith works as CurryWith but panics where CurryWith would have
+// returned an error.
+func (v *GaugeVec) MustCurryWith(labels Labels) *GaugeVec {
+	vec, err := v.CurryWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return vec
 }
 
 // GaugeFunc is a Gauge whose value is determined at collect time by calling a
@@ -127,9 +273,12 @@ type GaugeFunc interface {
 // NewGaugeFunc creates a new GaugeFunc based on the provided GaugeOpts. The
 // value reported is determined by calling the given function from within the
 // Write method. Take into account that metric collection may happen
-// concurrently. If that results in concurrent calls to Write, like in the case
-// where a GaugeFunc is directly registered with Prometheus, the provided
-// function must be concurrency-safe.
+// concurrently. Therefore, it must be safe to call the provided function
+// concurrently.
+//
+// NewGaugeFunc is a good way to create an “info” style metric with a constant
+// value of 1. Example:
+// https://github.com/prometheus/common/blob/8558a5b7db3c84fa38b4766966059a7bd5bfa2ee/version/info.go#L36-L56
 func NewGaugeFunc(opts GaugeOpts, function func() float64) GaugeFunc {
 	return newValueFunc(NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),

vendor/github.com/prometheus/client_golang/prometheus/go_collector.go

@@ -1,34 +1,89 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package prometheus
 
 import (
-	"fmt"
 	"runtime"
 	"runtime/debug"
+	"sync"
 	"time"
 )
 
 type goCollector struct {
-	goroutines Gauge
-	gcDesc     *Desc
+	goroutinesDesc *Desc
+	threadsDesc    *Desc
+	gcDesc         *Desc
+	goInfoDesc     *Desc
 
-	// metrics to describe and collect
-	metrics memStatsMetrics
+	// ms... are memstats related.
+	msLast          *runtime.MemStats // Previously collected memstats.
+	msLastTimestamp time.Time
+	msMtx           sync.Mutex // Protects msLast and msLastTimestamp.
+	msMetrics       memStatsMetrics
+	msRead          func(*runtime.MemStats) // For mocking in tests.
+	msMaxWait       time.Duration           // Wait time for fresh memstats.
+	msMaxAge        time.Duration           // Maximum allowed age of old memstats.
 }
 
-// NewGoCollector returns a collector which exports metrics about the current
-// go process.
+// NewGoCollector returns a collector that exports metrics about the current Go
+// process. This includes memory stats. To collect those, runtime.ReadMemStats
+// is called. This requires to “stop the world”, which usually only happens for
+// garbage collection (GC). Take the following implications into account when
+// deciding whether to use the Go collector:
+//
+// 1. The performance impact of stopping the world is the more relevant the more
+// frequently metrics are collected. However, with Go1.9 or later the
+// stop-the-world time per metrics collection is very short (~25µs) so that the
+// performance impact will only matter in rare cases. However, with older Go
+// versions, the stop-the-world duration depends on the heap size and can be
+// quite significant (~1.7 ms/GiB as per
+// https://go-review.googlesource.com/c/go/+/34937).
+//
+// 2. During an ongoing GC, nothing else can stop the world. Therefore, if the
+// metrics collection happens to coincide with GC, it will only complete after
+// GC has finished. Usually, GC is fast enough to not cause problems. However,
+// with a very large heap, GC might take multiple seconds, which is enough to
+// cause scrape timeouts in common setups. To avoid this problem, the Go
+// collector will use the memstats from a previous collection if
+// runtime.ReadMemStats takes more than 1s. However, if there are no previously
+// collected memstats, or their collection is more than 5m ago, the collection
+// will block until runtime.ReadMemStats succeeds. (The problem might be solved
+// in Go1.13, see https://github.com/golang/go/issues/19812 for the related Go
+// issue.)
 func NewGoCollector() Collector {
 	return &goCollector{
-		goroutines: NewGauge(GaugeOpts{
-			Namespace: "go",
-			Name:      "goroutines",
-			Help:      "Number of goroutines that currently exist.",
-		}),
+		goroutinesDesc: NewDesc(
+			"go_goroutines",
+			"Number of goroutines that currently exist.",
+			nil, nil),
+		threadsDesc: NewDesc(
+			"go_threads",
+			"Number of OS threads created.",
+			nil, nil),
 		gcDesc: NewDesc(
 			"go_gc_duration_seconds",
-			"A summary of the GC invocation durations.",
+			"A summary of the pause duration of garbage collection cycles.",
 			nil, nil),
-		metrics: memStatsMetrics{
+		goInfoDesc: NewDesc(
+			"go_info",
+			"Information about the Go environment.",
+			nil, Labels{"version": runtime.Version()}),
+		msLast:    &runtime.MemStats{},
+		msRead:    runtime.ReadMemStats,
+		msMaxWait: time.Second,
+		msMaxAge:  5 * time.Minute,
+		msMetrics: memStatsMetrics{
 			{
 				desc: NewDesc(
 					memstatNamespace("alloc_bytes"),
@@ -48,7 +103,7 @@ func NewGoCollector() Collector {
 			}, {
 				desc: NewDesc(
 					memstatNamespace("sys_bytes"),
-					"Number of bytes obtained by system. Sum of all system allocations.",
+					"Number of bytes obtained from system.",
 					nil, nil,
 				),
 				eval:    func(ms *runtime.MemStats) float64 { return float64(ms.Sys) },
@@ -111,12 +166,12 @@ func NewGoCollector() Collector {
 				valType: GaugeValue,
 			}, {
 				desc: NewDesc(
-					memstatNamespace("heap_released_bytes_total"),
-					"Total number of heap bytes released to OS.",
+					memstatNamespace("heap_released_bytes"),
+					"Number of heap bytes released to OS.",
 					nil, nil,
 				),
 				eval:    func(ms *runtime.MemStats) float64 { return float64(ms.HeapReleased) },
-				valType: CounterValue,
+				valType: GaugeValue,
 			}, {
 				desc: NewDesc(
 					memstatNamespace("heap_objects"),
@@ -213,29 +268,53 @@ func NewGoCollector() Collector {
 				),
 				eval:    func(ms *runtime.MemStats) float64 { return float64(ms.LastGC) / 1e9 },
 				valType: GaugeValue,
+			}, {
+				desc: NewDesc(
+					memstatNamespace("gc_cpu_fraction"),
+					"The fraction of this program's available CPU time used by the GC since the program started.",
+					nil, nil,
+				),
+				eval:    func(ms *runtime.MemStats) float64 { return ms.GCCPUFraction },
+				valType: GaugeValue,
 			},
 		},
 	}
 }
 
 func memstatNamespace(s string) string {
-	return fmt.Sprintf("go_memstats_%s", s)
+	return "go_memstats_" + s
 }
 
 // Describe returns all descriptions of the collector.
 func (c *goCollector) Describe(ch chan<- *Desc) {
-	ch <- c.goroutines.Desc()
+	ch <- c.goroutinesDesc
+	ch <- c.threadsDesc
 	ch <- c.gcDesc
-
-	for _, i := range c.metrics {
+	ch <- c.goInfoDesc
+	for _, i := range c.msMetrics {
 		ch <- i.desc
 	}
 }
 
 // Collect returns the current state of all metrics of the collector.
 func (c *goCollector) Collect(ch chan<- Metric) {
-	c.goroutines.Set(float64(runtime.NumGoroutine()))
-	ch <- c.goroutines
+	var (
+		ms   = &runtime.MemStats{}
+		done = make(chan struct{})
+	)
+	// Start reading memstats first as it might take a while.
+	go func() {
+		c.msRead(ms)
+		c.msMtx.Lock()
+		c.msLast = ms
+		c.msLastTimestamp = time.Now()
+		c.msMtx.Unlock()
+		close(done)
+	}()
+
+	ch <- MustNewConstMetric(c.goroutinesDesc, GaugeValue, float64(runtime.NumGoroutine()))
+	n, _ := runtime.ThreadCreateProfile(nil)
+	ch <- MustNewConstMetric(c.threadsDesc, GaugeValue, float64(n))
 
 	var stats debug.GCStats
 	stats.PauseQuantiles = make([]time.Duration, 5)
@@ -246,11 +325,35 @@ func (c *goCollector) Collect(ch chan<- Metric) {
 		quantiles[float64(idx+1)/float64(len(stats.PauseQuantiles)-1)] = pq.Seconds()
 	}
 	quantiles[0.0] = stats.PauseQuantiles[0].Seconds()
-	ch <- MustNewConstSummary(c.gcDesc, uint64(stats.NumGC), float64(stats.PauseTotal.Seconds()), quantiles)
+	ch <- MustNewConstSummary(c.gcDesc, uint64(stats.NumGC), stats.PauseTotal.Seconds(), quantiles)
 
-	ms := &runtime.MemStats{}
-	runtime.ReadMemStats(ms)
-	for _, i := range c.metrics {
+	ch <- MustNewConstMetric(c.goInfoDesc, GaugeValue, 1)
+
+	timer := time.NewTimer(c.msMaxWait)
+	select {
+	case <-done: // Our own ReadMemStats succeeded in time. Use it.
+		timer.Stop() // Important for high collection frequencies to not pile up timers.
+		c.msCollect(ch, ms)
+		return
+	case <-timer.C: // Time out, use last memstats if possible. Continue below.
+	}
+	c.msMtx.Lock()
+	if time.Since(c.msLastTimestamp) < c.msMaxAge {
+		// Last memstats are recent enough. Collect from them under the lock.
+		c.msCollect(ch, c.msLast)
+		c.msMtx.Unlock()
+		return
+	}
+	// If we are here, the last memstats are too old or don't exist. We have
+	// to wait until our own ReadMemStats finally completes. For that to
+	// happen, we have to release the lock.
+	c.msMtx.Unlock()
+	<-done
+	c.msCollect(ch, ms)
+}
+
+func (c *goCollector) msCollect(ch chan<- Metric, ms *runtime.MemStats) {
+	for _, i := range c.msMetrics {
 		ch <- MustNewConstMetric(i.desc, i.valType, i.eval(ms))
 	}
 }
@@ -261,3 +364,33 @@ type memStatsMetrics []struct {
 	eval    func(*runtime.MemStats) float64
 	valType ValueType
 }
+
+// NewBuildInfoCollector returns a collector collecting a single metric
+// "go_build_info" with the constant value 1 and three labels "path", "version",
+// and "checksum". Their label values contain the main module path, version, and
+// checksum, respectively. The labels will only have meaningful values if the
+// binary is built with Go module support and from source code retrieved from
+// the source repository (rather than the local file system). This is usually
+// accomplished by building from outside of GOPATH, specifying the full address
+// of the main package, e.g. "GO111MODULE=on go run
+// github.com/prometheus/client_golang/examples/random". If built without Go
+// module support, all label values will be "unknown". If built with Go module
+// support but using the source code from the local file system, the "path" will
+// be set appropriately, but "checksum" will be empty and "version" will be
+// "(devel)".
+//
+// This collector uses only the build information for the main module. See
+// https://github.com/povilasv/prommod for an example of a collector for the
+// module dependencies.
+func NewBuildInfoCollector() Collector {
+	path, version, sum := readBuildInfo()
+	c := &selfCollector{MustNewConstMetric(
+		NewDesc(
+			"go_build_info",
+			"Build information about the main Go module.",
+			nil, Labels{"path": path, "version": version, "checksum": sum},
+		),
+		GaugeValue, 1)}
+	c.init(c.self)
+	return c
+}

vendor/github.com/prometheus/client_golang/prometheus/histogram.go

@@ -16,8 +16,11 @@ package prometheus
 import (
 	"fmt"
 	"math"
+	"runtime"
 	"sort"
+	"sync"
 	"sync/atomic"
+	"time"
 
 	"github.com/golang/protobuf/proto"
 
@@ -108,8 +111,9 @@ func ExponentialBuckets(start, factor float64, count int) []float64 {
 }
 
 // HistogramOpts bundles the options for creating a Histogram metric. It is
-// mandatory to set Name and Help to a non-empty string. All other fields are
-// optional and can safely be left at their zero value.
+// mandatory to set Name to a non-empty string. All other fields are optional
+// and can safely be left at their zero value, although it is strongly
+// encouraged to set a Help string.
 type HistogramOpts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Histogram (created by joining these components with
@@ -120,29 +124,22 @@ type HistogramOpts struct {
 	Subsystem string
 	Name      string
 
-	// Help provides information about this Histogram. Mandatory!
+	// Help provides information about this Histogram.
 	//
 	// Metrics with the same fully-qualified name must have the same Help
 	// string.
 	Help string
 
-	// ConstLabels are used to attach fixed labels to this
-	// Histogram. Histograms with the same fully-qualified name must have the
-	// same label names in their ConstLabels.
+	// ConstLabels are used to attach fixed labels to this metric. Metrics
+	// with the same fully-qualified name must have the same label names in
+	// their ConstLabels.
 	//
-	// Note that in most cases, labels have a value that varies during the
-	// lifetime of a process. Those labels are usually managed with a
-	// HistogramVec. ConstLabels serve only special purposes. One is for the
-	// special case where the value of a label does not change during the
-	// lifetime of a process, e.g. if the revision of the running binary is
-	// put into a label. Another, more advanced purpose is if more than one
-	// Collector needs to collect Histograms with the same fully-qualified
-	// name. In that case, those Summaries must differ in the values of
-	// their ConstLabels. See the Collector examples.
-	//
-	// If the value of a label never changes (not even between binaries),
-	// that label most likely should not be a label at all (but part of the
-	// metric name).
+	// ConstLabels are only used rarely. In particular, do not use them to
+	// attach the same labels to all your metrics. Those use cases are
+	// better covered by target labels set by the scraping Prometheus
+	// server, or by one specific metric (e.g. a build_info or a
+	// machine_role metric). See also
+	// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels-not-static-scraped-labels
 	ConstLabels Labels
 
 	// Buckets defines the buckets into which observations are counted. Each
@@ -155,6 +152,10 @@ type HistogramOpts struct {
 
 // NewHistogram creates a new Histogram based on the provided HistogramOpts. It
 // panics if the buckets in HistogramOpts are not in strictly increasing order.
+//
+// The returned implementation also implements ExemplarObserver. It is safe to
+// perform the corresponding type assertion. Exemplars are tracked separately
+// for each bucket.
 func NewHistogram(opts HistogramOpts) Histogram {
 	return newHistogram(
 		NewDesc(
@@ -169,7 +170,7 @@ func NewHistogram(opts HistogramOpts) Histogram {
 
 func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogram {
 	if len(desc.variableLabels) != len(labelValues) {
-		panic(errInconsistentCardinality)
+		panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, labelValues))
 	}
 
 	for _, n := range desc.variableLabels {
@@ -191,6 +192,8 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 		desc:        desc,
 		upperBounds: opts.Buckets,
 		labelPairs:  makeLabelPairs(desc, labelValues),
+		counts:      [2]*histogramCounts{{}, {}},
+		now:         time.Now,
 	}
 	for i, upperBound := range h.upperBounds {
 		if i < len(h.upperBounds)-1 {
@@ -207,30 +210,60 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 			}
 		}
 	}
-	// Finally we know the final length of h.upperBounds and can make counts.
-	h.counts = make([]uint64, len(h.upperBounds))
+	// Finally we know the final length of h.upperBounds and can make buckets
+	// for both counts as well as exemplars:
+	h.counts[0].buckets = make([]uint64, len(h.upperBounds))
+	h.counts[1].buckets = make([]uint64, len(h.upperBounds))
+	h.exemplars = make([]atomic.Value, len(h.upperBounds)+1)
 
 	h.init(h) // Init self-collection.
 	return h
 }
 
-type histogram struct {
+type histogramCounts struct {
 	// sumBits contains the bits of the float64 representing the sum of all
 	// observations. sumBits and count have to go first in the struct to
 	// guarantee alignment for atomic operations.
 	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
 	sumBits uint64
 	count   uint64
+	buckets []uint64
+}
+
+type histogram struct {
+	// countAndHotIdx enables lock-free writes with use of atomic updates.
+	// The most significant bit is the hot index [0 or 1] of the count field
+	// below. Observe calls update the hot one. All remaining bits count the
+	// number of Observe calls. Observe starts by incrementing this counter,
+	// and finish by incrementing the count field in the respective
+	// histogramCounts, as a marker for completion.
+	//
+	// Calls of the Write method (which are non-mutating reads from the
+	// perspective of the histogram) swap the hot–cold under the writeMtx
+	// lock. A cooldown is awaited (while locked) by comparing the number of
+	// observations with the initiation count. Once they match, then the
+	// last observation on the now cool one has completed. All cool fields must
+	// be merged into the new hot before releasing writeMtx.
+	//
+	// Fields with atomic access first! See alignment constraint:
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	countAndHotIdx uint64
 
 	selfCollector
-	// Note that there is no mutex required.
+	desc     *Desc
+	writeMtx sync.Mutex // Only used in the Write method.
 
-	desc *Desc
+	// Two counts, one is "hot" for lock-free observations, the other is
+	// "cold" for writing out a dto.Metric. It has to be an array of
+	// pointers to guarantee 64bit alignment of the histogramCounts, see
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG.
+	counts [2]*histogramCounts
 
 	upperBounds []float64
-	counts      []uint64
+	labelPairs  []*dto.LabelPair
+	exemplars   []atomic.Value // One more than buckets (to include +Inf), each a *dto.Exemplar.
 
-	labelPairs []*dto.LabelPair
+	now func() time.Time // To mock out time.Now() for testing.
 }
 
 func (h *histogram) Desc() *Desc {
@@ -238,6 +271,89 @@ func (h *histogram) Desc() *Desc {
 }
 
 func (h *histogram) Observe(v float64) {
+	h.observe(v, h.findBucket(v))
+}
+
+func (h *histogram) ObserveWithExemplar(v float64, e Labels) {
+	i := h.findBucket(v)
+	h.observe(v, i)
+	h.updateExemplar(v, i, e)
+}
+
+func (h *histogram) Write(out *dto.Metric) error {
+	// For simplicity, we protect this whole method by a mutex. It is not in
+	// the hot path, i.e. Observe is called much more often than Write. The
+	// complication of making Write lock-free isn't worth it, if possible at
+	// all.
+	h.writeMtx.Lock()
+	defer h.writeMtx.Unlock()
+
+	// Adding 1<<63 switches the hot index (from 0 to 1 or from 1 to 0)
+	// without touching the count bits. See the struct comments for a full
+	// description of the algorithm.
+	n := atomic.AddUint64(&h.countAndHotIdx, 1<<63)
+	// count is contained unchanged in the lower 63 bits.
+	count := n & ((1 << 63) - 1)
+	// The most significant bit tells us which counts is hot. The complement
+	// is thus the cold one.
+	hotCounts := h.counts[n>>63]
+	coldCounts := h.counts[(^n)>>63]
+
+	// Await cooldown.
+	for count != atomic.LoadUint64(&coldCounts.count) {
+		runtime.Gosched() // Let observations get work done.
+	}
+
+	his := &dto.Histogram{
+		Bucket:      make([]*dto.Bucket, len(h.upperBounds)),
+		SampleCount: proto.Uint64(count),
+		SampleSum:   proto.Float64(math.Float64frombits(atomic.LoadUint64(&coldCounts.sumBits))),
+	}
+	var cumCount uint64
+	for i, upperBound := range h.upperBounds {
+		cumCount += atomic.LoadUint64(&coldCounts.buckets[i])
+		his.Bucket[i] = &dto.Bucket{
+			CumulativeCount: proto.Uint64(cumCount),
+			UpperBound:      proto.Float64(upperBound),
+		}
+		if e := h.exemplars[i].Load(); e != nil {
+			his.Bucket[i].Exemplar = e.(*dto.Exemplar)
+		}
+	}
+	// If there is an exemplar for the +Inf bucket, we have to add that bucket explicitly.
+	if e := h.exemplars[len(h.upperBounds)].Load(); e != nil {
+		b := &dto.Bucket{
+			CumulativeCount: proto.Uint64(count),
+			UpperBound:      proto.Float64(math.Inf(1)),
+			Exemplar:        e.(*dto.Exemplar),
+		}
+		his.Bucket = append(his.Bucket, b)
+	}
+
+	out.Histogram = his
+	out.Label = h.labelPairs
+
+	// Finally add all the cold counts to the new hot counts and reset the cold counts.
+	atomic.AddUint64(&hotCounts.count, count)
+	atomic.StoreUint64(&coldCounts.count, 0)
+	for {
+		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + his.GetSampleSum())
+		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
+			atomic.StoreUint64(&coldCounts.sumBits, 0)
+			break
+		}
+	}
+	for i := range h.upperBounds {
+		atomic.AddUint64(&hotCounts.buckets[i], atomic.LoadUint64(&coldCounts.buckets[i]))
+		atomic.StoreUint64(&coldCounts.buckets[i], 0)
+	}
+	return nil
+}
+
+// findBucket returns the index of the bucket for the provided value, or
+// len(h.upperBounds) for the +Inf bucket.
+func (h *histogram) findBucket(v float64) int {
 	// TODO(beorn7): For small numbers of buckets (<30), a linear search is
 	// slightly faster than the binary search. If we really care, we could
 	// switch from one search strategy to the other depending on the number
@@ -247,38 +363,43 @@ func (h *histogram) Observe(v float64) {
 	// 11 buckets: 38.3 ns/op linear - binary 48.7 ns/op
 	// 100 buckets: 78.1 ns/op linear - binary 54.9 ns/op
 	// 300 buckets: 154 ns/op linear - binary 61.6 ns/op
-	i := sort.SearchFloat64s(h.upperBounds, v)
-	if i < len(h.counts) {
-		atomic.AddUint64(&h.counts[i], 1)
+	return sort.SearchFloat64s(h.upperBounds, v)
+}
+
+// observe is the implementation for Observe without the findBucket part.
+func (h *histogram) observe(v float64, bucket int) {
+	// We increment h.countAndHotIdx so that the counter in the lower
+	// 63 bits gets incremented. At the same time, we get the new value
+	// back, which we can use to find the currently-hot counts.
+	n := atomic.AddUint64(&h.countAndHotIdx, 1)
+	hotCounts := h.counts[n>>63]
+
+	if bucket < len(h.upperBounds) {
+		atomic.AddUint64(&hotCounts.buckets[bucket], 1)
 	}
-	atomic.AddUint64(&h.count, 1)
 	for {
-		oldBits := atomic.LoadUint64(&h.sumBits)
+		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
 		newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
-		if atomic.CompareAndSwapUint64(&h.sumBits, oldBits, newBits) {
+		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
 			break
 		}
 	}
+	// Increment count last as we take it as a signal that the observation
+	// is complete.
+	atomic.AddUint64(&hotCounts.count, 1)
 }
 
-func (h *histogram) Write(out *dto.Metric) error {
-	his := &dto.Histogram{}
-	buckets := make([]*dto.Bucket, len(h.upperBounds))
-
-	his.SampleSum = proto.Float64(math.Float64frombits(atomic.LoadUint64(&h.sumBits)))
-	his.SampleCount = proto.Uint64(atomic.LoadUint64(&h.count))
-	var count uint64
-	for i, upperBound := range h.upperBounds {
-		count += atomic.LoadUint64(&h.counts[i])
-		buckets[i] = &dto.Bucket{
-			CumulativeCount: proto.Uint64(count),
-			UpperBound:      proto.Float64(upperBound),
-		}
+// updateExemplar replaces the exemplar for the provided bucket. With empty
+// labels, it's a no-op. It panics if any of the labels is invalid.
+func (h *histogram) updateExemplar(v float64, bucket int, l Labels) {
+	if l == nil {
+		return
 	}
-	his.Bucket = buckets
-	out.Histogram = his
-	out.Label = h.labelPairs
-	return nil
+	e, err := newExemplar(v, h.now(), l)
+	if err != nil {
+		panic(err)
+	}
+	h.exemplars[bucket].Store(e)
 }
 
 // HistogramVec is a Collector that bundles a set of Histograms that all share the
@@ -287,12 +408,11 @@ func (h *histogram) Write(out *dto.Metric) error {
 // (e.g. HTTP request latencies, partitioned by status code and method). Create
 // instances with NewHistogramVec.
 type HistogramVec struct {
-	*MetricVec
+	*metricVec
 }
 
 // NewHistogramVec creates a new HistogramVec based on the provided HistogramOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
+// partitioned by the given label names.
 func NewHistogramVec(opts HistogramOpts, labelNames []string) *HistogramVec {
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
@@ -301,47 +421,116 @@ func NewHistogramVec(opts HistogramOpts, labelNames []string) *HistogramVec {
 		opts.ConstLabels,
 	)
 	return &HistogramVec{
-		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
+		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			return newHistogram(desc, opts, lvs...)
 		}),
 	}
 }
 
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns a Histogram and not a
-// Metric so that no type conversion is required.
-func (m *HistogramVec) GetMetricWithLabelValues(lvs ...string) (Histogram, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
+// GetMetricWithLabelValues returns the Histogram for the given slice of label
+// values (same order as the VariableLabels in Desc). If that combination of
+// label values is accessed for the first time, a new Histogram is created.
+//
+// It is possible to call this method without using the returned Histogram to only
+// create the new Histogram but leave it at its starting value, a Histogram without
+// any observations.
+//
+// Keeping the Histogram for later use is possible (and should be considered if
+// performance is critical), but keep in mind that Reset, DeleteLabelValues and
+// Delete can be used to delete the Histogram from the HistogramVec. In that case, the
+// Histogram will still exist, but it will not be exported anymore, even if a
+// Histogram with the same label values is created later. See also the CounterVec
+// example.
+//
+// An error is returned if the number of label values is not the same as the
+// number of VariableLabels in Desc (minus any curried labels).
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
+// an alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
+// See also the GaugeVec example.
+func (v *HistogramVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) {
+	metric, err := v.metricVec.getMetricWithLabelValues(lvs...)
 	if metric != nil {
-		return metric.(Histogram), err
+		return metric.(Observer), err
 	}
 	return nil, err
 }
 
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns a Histogram and not a Metric so that no
-// type conversion is required.
-func (m *HistogramVec) GetMetricWith(labels Labels) (Histogram, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
+// GetMetricWith returns the Histogram for the given Labels map (the label names
+// must match those of the VariableLabels in Desc). If that label map is
+// accessed for the first time, a new Histogram is created. Implications of
+// creating a Histogram without using it and keeping the Histogram for later use
+// are the same as for GetMetricWithLabelValues.
+//
+// An error is returned if the number and names of the Labels are inconsistent
+// with those of the VariableLabels in Desc (minus any curried labels).
+//
+// This method is used for the same purpose as
+// GetMetricWithLabelValues(...string). See there for pros and cons of the two
+// methods.
+func (v *HistogramVec) GetMetricWith(labels Labels) (Observer, error) {
+	metric, err := v.metricVec.getMetricWith(labels)
 	if metric != nil {
-		return metric.(Histogram), err
+		return metric.(Observer), err
 	}
 	return nil, err
 }
 
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
+// GetMetricWithLabelValues would have returned an error. Not returning an
+// error allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Observe(42.21)
-func (m *HistogramVec) WithLabelValues(lvs ...string) Histogram {
-	return m.MetricVec.WithLabelValues(lvs...).(Histogram)
+func (v *HistogramVec) WithLabelValues(lvs ...string) Observer {
+	h, err := v.GetMetricWithLabelValues(lvs...)
+	if err != nil {
+		panic(err)
+	}
+	return h
 }
 
-// With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Observe(42.21)
-func (m *HistogramVec) With(labels Labels) Histogram {
-	return m.MetricVec.With(labels).(Histogram)
+// With works as GetMetricWith but panics where GetMetricWithLabels would have
+// returned an error. Not returning an error allows shortcuts like
+//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Observe(42.21)
+func (v *HistogramVec) With(labels Labels) Observer {
+	h, err := v.GetMetricWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return h
+}
+
+// CurryWith returns a vector curried with the provided labels, i.e. the
+// returned vector has those labels pre-set for all labeled operations performed
+// on it. The cardinality of the curried vector is reduced accordingly. The
+// order of the remaining labels stays the same (just with the curried labels
+// taken out of the sequence – which is relevant for the
+// (GetMetric)WithLabelValues methods). It is possible to curry a curried
+// vector, but only with labels not yet used for currying before.
+//
+// The metrics contained in the HistogramVec are shared between the curried and
+// uncurried vectors. They are just accessed differently. Curried and uncurried
+// vectors behave identically in terms of collection. Only one must be
+// registered with a given registry (usually the uncurried version). The Reset
+// method deletes all metrics, even if called on a curried vector.
+func (v *HistogramVec) CurryWith(labels Labels) (ObserverVec, error) {
+	vec, err := v.curryWith(labels)
+	if vec != nil {
+		return &HistogramVec{vec}, err
+	}
+	return nil, err
+}
+
+// MustCurryWith works as CurryWith but panics where CurryWith would have
+// returned an error.
+func (v *HistogramVec) MustCurryWith(labels Labels) ObserverVec {
+	vec, err := v.CurryWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return vec
 }
 
 type constHistogram struct {
@@ -393,7 +582,7 @@ func (h *constHistogram) Write(out *dto.Metric) error {
 // bucket.
 //
 // NewConstHistogram returns an error if the length of labelValues is not
-// consistent with the variable labels in Desc.
+// consistent with the variable labels in Desc or if Desc is invalid.
 func NewConstHistogram(
 	desc *Desc,
 	count uint64,
@@ -401,8 +590,11 @@ func NewConstHistogram(
 	buckets map[float64]uint64,
 	labelValues ...string,
 ) (Metric, error) {
-	if len(desc.variableLabels) != len(labelValues) {
-		return nil, errInconsistentCardinality
+	if desc.err != nil {
+		return nil, desc.err
+	}
+	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
+		return nil, err
 	}
 	return &constHistogram{
 		desc:       desc,

vendor/github.com/prometheus/client_golang/prometheus/http.go

@@ -1,490 +0,0 @@
-// Copyright 2014 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package prometheus
-
-import (
-	"bufio"
-	"bytes"
-	"compress/gzip"
-	"fmt"
-	"io"
-	"net"
-	"net/http"
-	"strconv"
-	"strings"
-	"sync"
-	"time"
-
-	"github.com/prometheus/common/expfmt"
-)
-
-// TODO(beorn7): Remove this whole file. It is a partial mirror of
-// promhttp/http.go (to avoid circular import chains) where everything HTTP
-// related should live. The functions here are just for avoiding
-// breakage. Everything is deprecated.
-
-const (
-	contentTypeHeader     = "Content-Type"
-	contentLengthHeader   = "Content-Length"
-	contentEncodingHeader = "Content-Encoding"
-	acceptEncodingHeader  = "Accept-Encoding"
-)
-
-var bufPool sync.Pool
-
-func getBuf() *bytes.Buffer {
-	buf := bufPool.Get()
-	if buf == nil {
-		return &bytes.Buffer{}
-	}
-	return buf.(*bytes.Buffer)
-}
-
-func giveBuf(buf *bytes.Buffer) {
-	buf.Reset()
-	bufPool.Put(buf)
-}
-
-// Handler returns an HTTP handler for the DefaultGatherer. It is
-// already instrumented with InstrumentHandler (using "prometheus" as handler
-// name).
-//
-// Deprecated: Please note the issues described in the doc comment of
-// InstrumentHandler. You might want to consider using promhttp.Handler instead
-// (which is non instrumented).
-func Handler() http.Handler {
-	return InstrumentHandler("prometheus", UninstrumentedHandler())
-}
-
-// UninstrumentedHandler returns an HTTP handler for the DefaultGatherer.
-//
-// Deprecated: Use promhttp.Handler instead. See there for further documentation.
-func UninstrumentedHandler() http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
-		mfs, err := DefaultGatherer.Gather()
-		if err != nil {
-			http.Error(w, "An error has occurred during metrics collection:\n\n"+err.Error(), http.StatusInternalServerError)
-			return
-		}
-
-		contentType := expfmt.Negotiate(req.Header)
-		buf := getBuf()
-		defer giveBuf(buf)
-		writer, encoding := decorateWriter(req, buf)
-		enc := expfmt.NewEncoder(writer, contentType)
-		var lastErr error
-		for _, mf := range mfs {
-			if err := enc.Encode(mf); err != nil {
-				lastErr = err
-				http.Error(w, "An error has occurred during metrics encoding:\n\n"+err.Error(), http.StatusInternalServerError)
-				return
-			}
-		}
-		if closer, ok := writer.(io.Closer); ok {
-			closer.Close()
-		}
-		if lastErr != nil && buf.Len() == 0 {
-			http.Error(w, "No metrics encoded, last error:\n\n"+err.Error(), http.StatusInternalServerError)
-			return
-		}
-		header := w.Header()
-		header.Set(contentTypeHeader, string(contentType))
-		header.Set(contentLengthHeader, fmt.Sprint(buf.Len()))
-		if encoding != "" {
-			header.Set(contentEncodingHeader, encoding)
-		}
-		w.Write(buf.Bytes())
-	})
-}
-
-// decorateWriter wraps a writer to handle gzip compression if requested.  It
-// returns the decorated writer and the appropriate "Content-Encoding" header
-// (which is empty if no compression is enabled).
-func decorateWriter(request *http.Request, writer io.Writer) (io.Writer, string) {
-	header := request.Header.Get(acceptEncodingHeader)
-	parts := strings.Split(header, ",")
-	for _, part := range parts {
-		part := strings.TrimSpace(part)
-		if part == "gzip" || strings.HasPrefix(part, "gzip;") {
-			return gzip.NewWriter(writer), "gzip"
-		}
-	}
-	return writer, ""
-}
-
-var instLabels = []string{"method", "code"}
-
-type nower interface {
-	Now() time.Time
-}
-
-type nowFunc func() time.Time
-
-func (n nowFunc) Now() time.Time {
-	return n()
-}
-
-var now nower = nowFunc(func() time.Time {
-	return time.Now()
-})
-
-func nowSeries(t ...time.Time) nower {
-	return nowFunc(func() time.Time {
-		defer func() {
-			t = t[1:]
-		}()
-
-		return t[0]
-	})
-}
-
-// InstrumentHandler wraps the given HTTP handler for instrumentation. It
-// registers four metric collectors (if not already done) and reports HTTP
-// metrics to the (newly or already) registered collectors: http_requests_total
-// (CounterVec), http_request_duration_microseconds (Summary),
-// http_request_size_bytes (Summary), http_response_size_bytes (Summary). Each
-// has a constant label named "handler" with the provided handlerName as
-// value. http_requests_total is a metric vector partitioned by HTTP method
-// (label name "method") and HTTP status code (label name "code").
-//
-// Deprecated: InstrumentHandler has several issues:
-//
-// - It uses Summaries rather than Histograms. Summaries are not useful if
-// aggregation across multiple instances is required.
-//
-// - It uses microseconds as unit, which is deprecated and should be replaced by
-// seconds.
-//
-// - The size of the request is calculated in a separate goroutine. Since this
-// calculator requires access to the request header, it creates a race with
-// any writes to the header performed during request handling.
-// httputil.ReverseProxy is a prominent example for a handler
-// performing such writes.
-//
-// Upcoming versions of this package will provide ways of instrumenting HTTP
-// handlers that are more flexible and have fewer issues. Please prefer direct
-// instrumentation in the meantime.
-func InstrumentHandler(handlerName string, handler http.Handler) http.HandlerFunc {
-	return InstrumentHandlerFunc(handlerName, handler.ServeHTTP)
-}
-
-// InstrumentHandlerFunc wraps the given function for instrumentation. It
-// otherwise works in the same way as InstrumentHandler (and shares the same
-// issues).
-//
-// Deprecated: InstrumentHandlerFunc is deprecated for the same reasons as
-// InstrumentHandler is.
-func InstrumentHandlerFunc(handlerName string, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc {
-	return InstrumentHandlerFuncWithOpts(
-		SummaryOpts{
-			Subsystem:   "http",
-			ConstLabels: Labels{"handler": handlerName},
-		},
-		handlerFunc,
-	)
-}
-
-// InstrumentHandlerWithOpts works like InstrumentHandler (and shares the same
-// issues) but provides more flexibility (at the cost of a more complex call
-// syntax). As InstrumentHandler, this function registers four metric
-// collectors, but it uses the provided SummaryOpts to create them. However, the
-// fields "Name" and "Help" in the SummaryOpts are ignored. "Name" is replaced
-// by "requests_total", "request_duration_microseconds", "request_size_bytes",
-// and "response_size_bytes", respectively. "Help" is replaced by an appropriate
-// help string. The names of the variable labels of the http_requests_total
-// CounterVec are "method" (get, post, etc.), and "code" (HTTP status code).
-//
-// If InstrumentHandlerWithOpts is called as follows, it mimics exactly the
-// behavior of InstrumentHandler:
-//
-//     prometheus.InstrumentHandlerWithOpts(
-//         prometheus.SummaryOpts{
-//              Subsystem:   "http",
-//              ConstLabels: prometheus.Labels{"handler": handlerName},
-//         },
-//         handler,
-//     )
-//
-// Technical detail: "requests_total" is a CounterVec, not a SummaryVec, so it
-// cannot use SummaryOpts. Instead, a CounterOpts struct is created internally,
-// and all its fields are set to the equally named fields in the provided
-// SummaryOpts.
-//
-// Deprecated: InstrumentHandlerWithOpts is deprecated for the same reasons as
-// InstrumentHandler is.
-func InstrumentHandlerWithOpts(opts SummaryOpts, handler http.Handler) http.HandlerFunc {
-	return InstrumentHandlerFuncWithOpts(opts, handler.ServeHTTP)
-}
-
-// InstrumentHandlerFuncWithOpts works like InstrumentHandlerFunc (and shares
-// the same issues) but provides more flexibility (at the cost of a more complex
-// call syntax). See InstrumentHandlerWithOpts for details how the provided
-// SummaryOpts are used.
-//
-// Deprecated: InstrumentHandlerFuncWithOpts is deprecated for the same reasons
-// as InstrumentHandler is.
-func InstrumentHandlerFuncWithOpts(opts SummaryOpts, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc {
-	reqCnt := NewCounterVec(
-		CounterOpts{
-			Namespace:   opts.Namespace,
-			Subsystem:   opts.Subsystem,
-			Name:        "requests_total",
-			Help:        "Total number of HTTP requests made.",
-			ConstLabels: opts.ConstLabels,
-		},
-		instLabels,
-	)
-
-	opts.Name = "request_duration_microseconds"
-	opts.Help = "The HTTP request latencies in microseconds."
-	reqDur := NewSummary(opts)
-
-	opts.Name = "request_size_bytes"
-	opts.Help = "The HTTP request sizes in bytes."
-	reqSz := NewSummary(opts)
-
-	opts.Name = "response_size_bytes"
-	opts.Help = "The HTTP response sizes in bytes."
-	resSz := NewSummary(opts)
-
-	regReqCnt := MustRegisterOrGet(reqCnt).(*CounterVec)
-	regReqDur := MustRegisterOrGet(reqDur).(Summary)
-	regReqSz := MustRegisterOrGet(reqSz).(Summary)
-	regResSz := MustRegisterOrGet(resSz).(Summary)
-
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		now := time.Now()
-
-		delegate := &responseWriterDelegator{ResponseWriter: w}
-		out := make(chan int)
-		urlLen := 0
-		if r.URL != nil {
-			urlLen = len(r.URL.String())
-		}
-		go computeApproximateRequestSize(r, out, urlLen)
-
-		_, cn := w.(http.CloseNotifier)
-		_, fl := w.(http.Flusher)
-		_, hj := w.(http.Hijacker)
-		_, rf := w.(io.ReaderFrom)
-		var rw http.ResponseWriter
-		if cn && fl && hj && rf {
-			rw = &fancyResponseWriterDelegator{delegate}
-		} else {
-			rw = delegate
-		}
-		handlerFunc(rw, r)
-
-		elapsed := float64(time.Since(now)) / float64(time.Microsecond)
-
-		method := sanitizeMethod(r.Method)
-		code := sanitizeCode(delegate.status)
-		regReqCnt.WithLabelValues(method, code).Inc()
-		regReqDur.Observe(elapsed)
-		regResSz.Observe(float64(delegate.written))
-		regReqSz.Observe(float64(<-out))
-	})
-}
-
-func computeApproximateRequestSize(r *http.Request, out chan int, s int) {
-	s += len(r.Method)
-	s += len(r.Proto)
-	for name, values := range r.Header {
-		s += len(name)
-		for _, value := range values {
-			s += len(value)
-		}
-	}
-	s += len(r.Host)
-
-	// N.B. r.Form and r.MultipartForm are assumed to be included in r.URL.
-
-	if r.ContentLength != -1 {
-		s += int(r.ContentLength)
-	}
-	out <- s
-}
-
-type responseWriterDelegator struct {
-	http.ResponseWriter
-
-	handler, method string
-	status          int
-	written         int64
-	wroteHeader     bool
-}
-
-func (r *responseWriterDelegator) WriteHeader(code int) {
-	r.status = code
-	r.wroteHeader = true
-	r.ResponseWriter.WriteHeader(code)
-}
-
-func (r *responseWriterDelegator) Write(b []byte) (int, error) {
-	if !r.wroteHeader {
-		r.WriteHeader(http.StatusOK)
-	}
-	n, err := r.ResponseWriter.Write(b)
-	r.written += int64(n)
-	return n, err
-}
-
-type fancyResponseWriterDelegator struct {
-	*responseWriterDelegator
-}
-
-func (f *fancyResponseWriterDelegator) CloseNotify() <-chan bool {
-	return f.ResponseWriter.(http.CloseNotifier).CloseNotify()
-}
-
-func (f *fancyResponseWriterDelegator) Flush() {
-	f.ResponseWriter.(http.Flusher).Flush()
-}
-
-func (f *fancyResponseWriterDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) {
-	return f.ResponseWriter.(http.Hijacker).Hijack()
-}
-
-func (f *fancyResponseWriterDelegator) ReadFrom(r io.Reader) (int64, error) {
-	if !f.wroteHeader {
-		f.WriteHeader(http.StatusOK)
-	}
-	n, err := f.ResponseWriter.(io.ReaderFrom).ReadFrom(r)
-	f.written += n
-	return n, err
-}
-
-func sanitizeMethod(m string) string {
-	switch m {
-	case "GET", "get":
-		return "get"
-	case "PUT", "put":
-		return "put"
-	case "HEAD", "head":
-		return "head"
-	case "POST", "post":
-		return "post"
-	case "DELETE", "delete":
-		return "delete"
-	case "CONNECT", "connect":
-		return "connect"
-	case "OPTIONS", "options":
-		return "options"
-	case "NOTIFY", "notify":
-		return "notify"
-	default:
-		return strings.ToLower(m)
-	}
-}
-
-func sanitizeCode(s int) string {
-	switch s {
-	case 100:
-		return "100"
-	case 101:
-		return "101"
-
-	case 200:
-		return "200"
-	case 201:
-		return "201"
-	case 202:
-		return "202"
-	case 203:
-		return "203"
-	case 204:
-		return "204"
-	case 205:
-		return "205"
-	case 206:
-		return "206"
-
-	case 300:
-		return "300"
-	case 301:
-		return "301"
-	case 302:
-		return "302"
-	case 304:
-		return "304"
-	case 305:
-		return "305"
-	case 307:
-		return "307"
-
-	case 400:
-		return "400"
-	case 401:
-		return "401"
-	case 402:
-		return "402"
-	case 403:
-		return "403"
-	case 404:
-		return "404"
-	case 405:
-		return "405"
-	case 406:
-		return "406"
-	case 407:
-		return "407"
-	case 408:
-		return "408"
-	case 409:
-		return "409"
-	case 410:
-		return "410"
-	case 411:
-		return "411"
-	case 412:
-		return "412"
-	case 413:
-		return "413"
-	case 414:
-		return "414"
-	case 415:
-		return "415"
-	case 416:
-		return "416"
-	case 417:
-		return "417"
-	case 418:
-		return "418"
-
-	case 500:
-		return "500"
-	case 501:
-		return "501"
-	case 502:
-		return "502"
-	case 503:
-		return "503"
-	case 504:
-		return "504"
-	case 505:
-		return "505"
-
-	case 428:
-		return "428"
-	case 429:
-		return "429"
-	case 431:
-		return "431"
-	case 511:
-		return "511"
-
-	default:
-		return strconv.Itoa(s)
-	}
-}

vendor/github.com/prometheus/client_golang/prometheus/internal/metric.go

@@ -0,0 +1,85 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internal
+
+import (
+	"sort"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
+// metricSorter is a sortable slice of *dto.Metric.
+type metricSorter []*dto.Metric
+
+func (s metricSorter) Len() int {
+	return len(s)
+}
+
+func (s metricSorter) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+func (s metricSorter) Less(i, j int) bool {
+	if len(s[i].Label) != len(s[j].Label) {
+		// This should not happen. The metrics are
+		// inconsistent. However, we have to deal with the fact, as
+		// people might use custom collectors or metric family injection
+		// to create inconsistent metrics. So let's simply compare the
+		// number of labels in this case. That will still yield
+		// reproducible sorting.
+		return len(s[i].Label) < len(s[j].Label)
+	}
+	for n, lp := range s[i].Label {
+		vi := lp.GetValue()
+		vj := s[j].Label[n].GetValue()
+		if vi != vj {
+			return vi < vj
+		}
+	}
+
+	// We should never arrive here. Multiple metrics with the same
+	// label set in the same scrape will lead to undefined ingestion
+	// behavior. However, as above, we have to provide stable sorting
+	// here, even for inconsistent metrics. So sort equal metrics
+	// by their timestamp, with missing timestamps (implying "now")
+	// coming last.
+	if s[i].TimestampMs == nil {
+		return false
+	}
+	if s[j].TimestampMs == nil {
+		return true
+	}
+	return s[i].GetTimestampMs() < s[j].GetTimestampMs()
+}
+
+// NormalizeMetricFamilies returns a MetricFamily slice with empty
+// MetricFamilies pruned and the remaining MetricFamilies sorted by name within
+// the slice, with the contained Metrics sorted within each MetricFamily.
+func NormalizeMetricFamilies(metricFamiliesByName map[string]*dto.MetricFamily) []*dto.MetricFamily {
+	for _, mf := range metricFamiliesByName {
+		sort.Sort(metricSorter(mf.Metric))
+	}
+	names := make([]string, 0, len(metricFamiliesByName))
+	for name, mf := range metricFamiliesByName {
+		if len(mf.Metric) > 0 {
+			names = append(names, name)
+		}
+	}
+	sort.Strings(names)
+	result := make([]*dto.MetricFamily, 0, len(names))
+	for _, name := range names {
+		result = append(result, metricFamiliesByName[name])
+	}
+	return result
+}

vendor/github.com/prometheus/client_golang/prometheus/labels.go

@@ -0,0 +1,87 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"unicode/utf8"
+
+	"github.com/prometheus/common/model"
+)
+
+// Labels represents a collection of label name -> value mappings. This type is
+// commonly used with the With(Labels) and GetMetricWith(Labels) methods of
+// metric vector Collectors, e.g.:
+//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
+//
+// The other use-case is the specification of constant label pairs in Opts or to
+// create a Desc.
+type Labels map[string]string
+
+// reservedLabelPrefix is a prefix which is not legal in user-supplied
+// label names.
+const reservedLabelPrefix = "__"
+
+var errInconsistentCardinality = errors.New("inconsistent label cardinality")
+
+func makeInconsistentCardinalityError(fqName string, labels, labelValues []string) error {
+	return fmt.Errorf(
+		"%s: %q has %d variable labels named %q but %d values %q were provided",
+		errInconsistentCardinality, fqName,
+		len(labels), labels,
+		len(labelValues), labelValues,
+	)
+}
+
+func validateValuesInLabels(labels Labels, expectedNumberOfValues int) error {
+	if len(labels) != expectedNumberOfValues {
+		return fmt.Errorf(
+			"%s: expected %d label values but got %d in %#v",
+			errInconsistentCardinality, expectedNumberOfValues,
+			len(labels), labels,
+		)
+	}
+
+	for name, val := range labels {
+		if !utf8.ValidString(val) {
+			return fmt.Errorf("label %s: value %q is not valid UTF-8", name, val)
+		}
+	}
+
+	return nil
+}
+
+func validateLabelValues(vals []string, expectedNumberOfValues int) error {
+	if len(vals) != expectedNumberOfValues {
+		return fmt.Errorf(
+			"%s: expected %d label values but got %d in %#v",
+			errInconsistentCardinality, expectedNumberOfValues,
+			len(vals), vals,
+		)
+	}
+
+	for _, val := range vals {
+		if !utf8.ValidString(val) {
+			return fmt.Errorf("label value %q is not valid UTF-8", val)
+		}
+	}
+
+	return nil
+}
+
+func checkLabelName(l string) bool {
+	return model.LabelName(l).IsValid() && !strings.HasPrefix(l, reservedLabelPrefix)
+}

vendor/github.com/prometheus/client_golang/prometheus/metric.go

@@ -15,11 +15,15 @@ package prometheus
 
 import (
 	"strings"
+	"time"
+
+	"github.com/golang/protobuf/proto"
+	"github.com/prometheus/common/model"
 
 	dto "github.com/prometheus/client_model/go"
 )
 
-const separatorByte byte = 255
+var separatorByteSlice = []byte{model.SeparatorByte} // For convenient use with xxhash.
 
 // A Metric models a single sample value with its meta data being exported to
 // Prometheus. Implementations of Metric in this package are Gauge, Counter,
@@ -43,9 +47,8 @@ type Metric interface {
 	// While populating dto.Metric, it is the responsibility of the
 	// implementation to ensure validity of the Metric protobuf (like valid
 	// UTF-8 strings or syntactically valid metric and label names). It is
-	// recommended to sort labels lexicographically. (Implementers may find
-	// LabelPairSorter useful for that.) Callers of Write should still make
-	// sure of sorting if they depend on it.
+	// recommended to sort labels lexicographically. Callers of Write should
+	// still make sure of sorting if they depend on it.
 	Write(*dto.Metric) error
 	// TODO(beorn7): The original rationale of passing in a pre-allocated
 	// dto.Metric protobuf to save allocations has disappeared. The
@@ -57,8 +60,9 @@ type Metric interface {
 // implementation XXX has its own XXXOpts type, but in most cases, it is just be
 // an alias of this type (which might change when the requirement arises.)
 //
-// It is mandatory to set Name and Help to a non-empty string. All other fields
-// are optional and can safely be left at their zero value.
+// It is mandatory to set Name to a non-empty string. All other fields are
+// optional and can safely be left at their zero value, although it is strongly
+// encouraged to set a Help string.
 type Opts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Metric (created by joining these components with
@@ -69,7 +73,7 @@ type Opts struct {
 	Subsystem string
 	Name      string
 
-	// Help provides information about this metric. Mandatory!
+	// Help provides information about this metric.
 	//
 	// Metrics with the same fully-qualified name must have the same Help
 	// string.
@@ -79,20 +83,12 @@ type Opts struct {
 	// with the same fully-qualified name must have the same label names in
 	// their ConstLabels.
 	//
-	// Note that in most cases, labels have a value that varies during the
-	// lifetime of a process. Those labels are usually managed with a metric
-	// vector collector (like CounterVec, GaugeVec, UntypedVec). ConstLabels
-	// serve only special purposes. One is for the special case where the
-	// value of a label does not change during the lifetime of a process,
-	// e.g. if the revision of the running binary is put into a
-	// label. Another, more advanced purpose is if more than one Collector
-	// needs to collect Metrics with the same fully-qualified name. In that
-	// case, those Metrics must differ in the values of their
-	// ConstLabels. See the Collector examples.
-	//
-	// If the value of a label never changes (not even between binaries),
-	// that label most likely should not be a label at all (but part of the
-	// metric name).
+	// ConstLabels are only used rarely. In particular, do not use them to
+	// attach the same labels to all your metrics. Those use cases are
+	// better covered by target labels set by the scraping Prometheus
+	// server, or by one specific metric (e.g. a build_info or a
+	// machine_role metric). See also
+	// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels,-not-static-scraped-labels
 	ConstLabels Labels
 }
 
@@ -118,37 +114,22 @@ func BuildFQName(namespace, subsystem, name string) string {
 	return name
 }
 
-// LabelPairSorter implements sort.Interface. It is used to sort a slice of
-// dto.LabelPair pointers. This is useful for implementing the Write method of
-// custom metrics.
-type LabelPairSorter []*dto.LabelPair
+// labelPairSorter implements sort.Interface. It is used to sort a slice of
+// dto.LabelPair pointers.
+type labelPairSorter []*dto.LabelPair
 
-func (s LabelPairSorter) Len() int {
+func (s labelPairSorter) Len() int {
 	return len(s)
 }
 
-func (s LabelPairSorter) Swap(i, j int) {
+func (s labelPairSorter) Swap(i, j int) {
 	s[i], s[j] = s[j], s[i]
 }
 
-func (s LabelPairSorter) Less(i, j int) bool {
+func (s labelPairSorter) Less(i, j int) bool {
 	return s[i].GetName() < s[j].GetName()
 }
 
-type hashSorter []uint64
-
-func (s hashSorter) Len() int {
-	return len(s)
-}
-
-func (s hashSorter) Swap(i, j int) {
-	s[i], s[j] = s[j], s[i]
-}
-
-func (s hashSorter) Less(i, j int) bool {
-	return s[i] < s[j]
-}
-
 type invalidMetric struct {
 	desc *Desc
 	err  error
@@ -164,3 +145,31 @@ func NewInvalidMetric(desc *Desc, err error) Metric {
 func (m *invalidMetric) Desc() *Desc { return m.desc }
 
 func (m *invalidMetric) Write(*dto.Metric) error { return m.err }
+
+type timestampedMetric struct {
+	Metric
+	t time.Time
+}
+
+func (m timestampedMetric) Write(pb *dto.Metric) error {
+	e := m.Metric.Write(pb)
+	pb.TimestampMs = proto.Int64(m.t.Unix()*1000 + int64(m.t.Nanosecond()/1000000))
+	return e
+}
+
+// NewMetricWithTimestamp returns a new Metric wrapping the provided Metric in a
+// way that it has an explicit timestamp set to the provided Time. This is only
+// useful in rare cases as the timestamp of a Prometheus metric should usually
+// be set by the Prometheus server during scraping. Exceptions include mirroring
+// metrics with given timestamps from other metric
+// sources.
+//
+// NewMetricWithTimestamp works best with MustNewConstMetric,
+// MustNewConstHistogram, and MustNewConstSummary, see example.
+//
+// Currently, the exposition formats used by Prometheus are limited to
+// millisecond resolution. Thus, the provided time will be rounded down to the
+// next full millisecond value.
+func NewMetricWithTimestamp(t time.Time, m Metric) Metric {
+	return timestampedMetric{Metric: m, t: t}
+}

vendor/github.com/prometheus/client_golang/prometheus/observer.go

@@ -0,0 +1,64 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+// Observer is the interface that wraps the Observe method, which is used by
+// Histogram and Summary to add observations.
+type Observer interface {
+	Observe(float64)
+}
+
+// The ObserverFunc type is an adapter to allow the use of ordinary
+// functions as Observers. If f is a function with the appropriate
+// signature, ObserverFunc(f) is an Observer that calls f.
+//
+// This adapter is usually used in connection with the Timer type, and there are
+// two general use cases:
+//
+// The most common one is to use a Gauge as the Observer for a Timer.
+// See the "Gauge" Timer example.
+//
+// The more advanced use case is to create a function that dynamically decides
+// which Observer to use for observing the duration. See the "Complex" Timer
+// example.
+type ObserverFunc func(float64)
+
+// Observe calls f(value). It implements Observer.
+func (f ObserverFunc) Observe(value float64) {
+	f(value)
+}
+
+// ObserverVec is an interface implemented by `HistogramVec` and `SummaryVec`.
+type ObserverVec interface {
+	GetMetricWith(Labels) (Observer, error)
+	GetMetricWithLabelValues(lvs ...string) (Observer, error)
+	With(Labels) Observer
+	WithLabelValues(...string) Observer
+	CurryWith(Labels) (ObserverVec, error)
+	MustCurryWith(Labels) ObserverVec
+
+	Collector
+}
+
+// ExemplarObserver is implemented by Observers that offer the option of
+// observing a value together with an exemplar. Its ObserveWithExemplar method
+// works like the Observe method of an Observer but also replaces the currently
+// saved exemplar (if any) with a new one, created from the provided value, the
+// current time as timestamp, and the provided Labels. Empty Labels will lead to
+// a valid (label-less) exemplar. But if Labels is nil, the current exemplar is
+// left in place. ObserveWithExemplar panics if any of the provided labels are
+// invalid or if the provided labels contain more than 64 runes in total.
+type ExemplarObserver interface {
+	ObserveWithExemplar(value float64, exemplar Labels)
+}

vendor/github.com/prometheus/client_golang/prometheus/process_collector.go

@@ -13,89 +13,126 @@
 
 package prometheus
 
-import "github.com/prometheus/procfs"
+import (
+	"errors"
+	"os"
+)
 
 type processCollector struct {
-	pid             int
 	collectFn       func(chan<- Metric)
 	pidFn           func() (int, error)
-	cpuTotal        Counter
-	openFDs, maxFDs Gauge
-	vsize, rss      Gauge
-	startTime       Gauge
+	reportErrors    bool
+	cpuTotal        *Desc
+	openFDs, maxFDs *Desc
+	vsize, maxVsize *Desc
+	rss             *Desc
+	startTime       *Desc
+}
+
+// ProcessCollectorOpts defines the behavior of a process metrics collector
+// created with NewProcessCollector.
+type ProcessCollectorOpts struct {
+	// PidFn returns the PID of the process the collector collects metrics
+	// for. It is called upon each collection. By default, the PID of the
+	// current process is used, as determined on construction time by
+	// calling os.Getpid().
+	PidFn func() (int, error)
+	// If non-empty, each of the collected metrics is prefixed by the
+	// provided string and an underscore ("_").
+	Namespace string
+	// If true, any error encountered during collection is reported as an
+	// invalid metric (see NewInvalidMetric). Otherwise, errors are ignored
+	// and the collected metrics will be incomplete. (Possibly, no metrics
+	// will be collected at all.) While that's usually not desired, it is
+	// appropriate for the common "mix-in" of process metrics, where process
+	// metrics are nice to have, but failing to collect them should not
+	// disrupt the collection of the remaining metrics.
+	ReportErrors bool
 }
 
 // NewProcessCollector returns a collector which exports the current state of
-// process metrics including cpu, memory and file descriptor usage as well as
-// the process start time for the given process id under the given namespace.
-func NewProcessCollector(pid int, namespace string) Collector {
-	return NewProcessCollectorPIDFn(
-		func() (int, error) { return pid, nil },
-		namespace,
-	)
-}
+// process metrics including CPU, memory and file descriptor usage as well as
+// the process start time. The detailed behavior is defined by the provided
+// ProcessCollectorOpts. The zero value of ProcessCollectorOpts creates a
+// collector for the current process with an empty namespace string and no error
+// reporting.
+//
+// The collector only works on operating systems with a Linux-style proc
+// filesystem and on Microsoft Windows. On other operating systems, it will not
+// collect any metrics.
+func NewProcessCollector(opts ProcessCollectorOpts) Collector {
+	ns := ""
+	if len(opts.Namespace) > 0 {
+		ns = opts.Namespace + "_"
+	}
 
-// NewProcessCollectorPIDFn returns a collector which exports the current state
-// of process metrics including cpu, memory and file descriptor usage as well
-// as the process start time under the given namespace. The given pidFn is
-// called on each collect and is used to determine the process to export
-// metrics for.
-func NewProcessCollectorPIDFn(
-	pidFn func() (int, error),
-	namespace string,
-) Collector {
-	c := processCollector{
-		pidFn:     pidFn,
-		collectFn: func(chan<- Metric) {},
+	c := &processCollector{
+		reportErrors: opts.ReportErrors,
+		cpuTotal: NewDesc(
+			ns+"process_cpu_seconds_total",
+			"Total user and system CPU time spent in seconds.",
+			nil, nil,
+		),
+		openFDs: NewDesc(
+			ns+"process_open_fds",
+			"Number of open file descriptors.",
+			nil, nil,
+		),
+		maxFDs: NewDesc(
+			ns+"process_max_fds",
+			"Maximum number of open file descriptors.",
+			nil, nil,
+		),
+		vsize: NewDesc(
+			ns+"process_virtual_memory_bytes",
+			"Virtual memory size in bytes.",
+			nil, nil,
+		),
+		maxVsize: NewDesc(
+			ns+"process_virtual_memory_max_bytes",
+			"Maximum amount of virtual memory available in bytes.",
+			nil, nil,
+		),
+		rss: NewDesc(
+			ns+"process_resident_memory_bytes",
+			"Resident memory size in bytes.",
+			nil, nil,
+		),
+		startTime: NewDesc(
+			ns+"process_start_time_seconds",
+			"Start time of the process since unix epoch in seconds.",
+			nil, nil,
+		),
+	}
 
-		cpuTotal: NewCounter(CounterOpts{
-			Namespace: namespace,
-			Name:      "process_cpu_seconds_total",
-			Help:      "Total user and system CPU time spent in seconds.",
-		}),
-		openFDs: NewGauge(GaugeOpts{
-			Namespace: namespace,
-			Name:      "process_open_fds",
-			Help:      "Number of open file descriptors.",
-		}),
-		maxFDs: NewGauge(GaugeOpts{
-			Namespace: namespace,
-			Name:      "process_max_fds",
-			Help:      "Maximum number of open file descriptors.",
-		}),
-		vsize: NewGauge(GaugeOpts{
-			Namespace: namespace,
-			Name:      "process_virtual_memory_bytes",
-			Help:      "Virtual memory size in bytes.",
-		}),
-		rss: NewGauge(GaugeOpts{
-			Namespace: namespace,
-			Name:      "process_resident_memory_bytes",
-			Help:      "Resident memory size in bytes.",
-		}),
-		startTime: NewGauge(GaugeOpts{
-			Namespace: namespace,
-			Name:      "process_start_time_seconds",
-			Help:      "Start time of the process since unix epoch in seconds.",
-		}),
+	if opts.PidFn == nil {
+		pid := os.Getpid()
+		c.pidFn = func() (int, error) { return pid, nil }
+	} else {
+		c.pidFn = opts.PidFn
 	}
 
 	// Set up process metric collection if supported by the runtime.
-	if _, err := procfs.NewStat(); err == nil {
+	if canCollectProcess() {
 		c.collectFn = c.processCollect
+	} else {
+		c.collectFn = func(ch chan<- Metric) {
+			c.reportError(ch, nil, errors.New("process metrics not supported on this platform"))
+		}
 	}
 
-	return &c
+	return c
 }
 
 // Describe returns all descriptions of the collector.
 func (c *processCollector) Describe(ch chan<- *Desc) {
-	ch <- c.cpuTotal.Desc()
-	ch <- c.openFDs.Desc()
-	ch <- c.maxFDs.Desc()
-	ch <- c.vsize.Desc()
-	ch <- c.rss.Desc()
-	ch <- c.startTime.Desc()
+	ch <- c.cpuTotal
+	ch <- c.openFDs
+	ch <- c.maxFDs
+	ch <- c.vsize
+	ch <- c.maxVsize
+	ch <- c.rss
+	ch <- c.startTime
 }
 
 // Collect returns the current state of all metrics of the collector.
@@ -103,40 +140,12 @@ func (c *processCollector) Collect(ch chan<- Metric) {
 	c.collectFn(ch)
 }
 
-// TODO(ts): Bring back error reporting by reverting 7faf9e7 as soon as the
-// client allows users to configure the error behavior.
-func (c *processCollector) processCollect(ch chan<- Metric) {
-	pid, err := c.pidFn()
-	if err != nil {
+func (c *processCollector) reportError(ch chan<- Metric, desc *Desc, err error) {
+	if !c.reportErrors {
 		return
 	}
-
-	p, err := procfs.NewProc(pid)
-	if err != nil {
-		return
-	}
-
-	if stat, err := p.NewStat(); err == nil {
-		c.cpuTotal.Set(stat.CPUTime())
-		ch <- c.cpuTotal
-		c.vsize.Set(float64(stat.VirtualMemory()))
-		ch <- c.vsize
-		c.rss.Set(float64(stat.ResidentMemory()))
-		ch <- c.rss
-
-		if startTime, err := stat.StartTime(); err == nil {
-			c.startTime.Set(startTime)
-			ch <- c.startTime
-		}
-	}
-
-	if fds, err := p.FileDescriptorsLen(); err == nil {
-		c.openFDs.Set(float64(fds))
-		ch <- c.openFDs
-	}
-
-	if limits, err := p.NewLimits(); err == nil {
-		c.maxFDs.Set(float64(limits.OpenFiles))
-		ch <- c.maxFDs
+	if desc == nil {
+		desc = NewInvalidDesc(err)
 	}
+	ch <- NewInvalidMetric(desc, err)
 }

vendor/github.com/prometheus/client_golang/prometheus/process_collector_other.go

@@ -0,0 +1,65 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !windows
+
+package prometheus
+
+import (
+	"github.com/prometheus/procfs"
+)
+
+func canCollectProcess() bool {
+	_, err := procfs.NewDefaultFS()
+	return err == nil
+}
+
+func (c *processCollector) processCollect(ch chan<- Metric) {
+	pid, err := c.pidFn()
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+
+	p, err := procfs.NewProc(pid)
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+
+	if stat, err := p.Stat(); err == nil {
+		ch <- MustNewConstMetric(c.cpuTotal, CounterValue, stat.CPUTime())
+		ch <- MustNewConstMetric(c.vsize, GaugeValue, float64(stat.VirtualMemory()))
+		ch <- MustNewConstMetric(c.rss, GaugeValue, float64(stat.ResidentMemory()))
+		if startTime, err := stat.StartTime(); err == nil {
+			ch <- MustNewConstMetric(c.startTime, GaugeValue, startTime)
+		} else {
+			c.reportError(ch, c.startTime, err)
+		}
+	} else {
+		c.reportError(ch, nil, err)
+	}
+
+	if fds, err := p.FileDescriptorsLen(); err == nil {
+		ch <- MustNewConstMetric(c.openFDs, GaugeValue, float64(fds))
+	} else {
+		c.reportError(ch, c.openFDs, err)
+	}
+
+	if limits, err := p.Limits(); err == nil {
+		ch <- MustNewConstMetric(c.maxFDs, GaugeValue, float64(limits.OpenFiles))
+		ch <- MustNewConstMetric(c.maxVsize, GaugeValue, float64(limits.AddressSpace))
+	} else {
+		c.reportError(ch, nil, err)
+	}
+}

vendor/github.com/prometheus/client_golang/prometheus/process_collector_windows.go

@@ -0,0 +1,116 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+func canCollectProcess() bool {
+	return true
+}
+
+var (
+	modpsapi    = syscall.NewLazyDLL("psapi.dll")
+	modkernel32 = syscall.NewLazyDLL("kernel32.dll")
+
+	procGetProcessMemoryInfo  = modpsapi.NewProc("GetProcessMemoryInfo")
+	procGetProcessHandleCount = modkernel32.NewProc("GetProcessHandleCount")
+)
+
+type processMemoryCounters struct {
+	// System interface description
+	// https://docs.microsoft.com/en-us/windows/desktop/api/psapi/ns-psapi-process_memory_counters_ex
+
+	// Refer to the Golang internal implementation
+	// https://golang.org/src/internal/syscall/windows/psapi_windows.go
+	_                          uint32
+	PageFaultCount             uint32
+	PeakWorkingSetSize         uintptr
+	WorkingSetSize             uintptr
+	QuotaPeakPagedPoolUsage    uintptr
+	QuotaPagedPoolUsage        uintptr
+	QuotaPeakNonPagedPoolUsage uintptr
+	QuotaNonPagedPoolUsage     uintptr
+	PagefileUsage              uintptr
+	PeakPagefileUsage          uintptr
+	PrivateUsage               uintptr
+}
+
+func getProcessMemoryInfo(handle windows.Handle) (processMemoryCounters, error) {
+	mem := processMemoryCounters{}
+	r1, _, err := procGetProcessMemoryInfo.Call(
+		uintptr(handle),
+		uintptr(unsafe.Pointer(&mem)),
+		uintptr(unsafe.Sizeof(mem)),
+	)
+	if r1 != 1 {
+		return mem, err
+	} else {
+		return mem, nil
+	}
+}
+
+func getProcessHandleCount(handle windows.Handle) (uint32, error) {
+	var count uint32
+	r1, _, err := procGetProcessHandleCount.Call(
+		uintptr(handle),
+		uintptr(unsafe.Pointer(&count)),
+	)
+	if r1 != 1 {
+		return 0, err
+	} else {
+		return count, nil
+	}
+}
+
+func (c *processCollector) processCollect(ch chan<- Metric) {
+	h, err := windows.GetCurrentProcess()
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+
+	var startTime, exitTime, kernelTime, userTime windows.Filetime
+	err = windows.GetProcessTimes(h, &startTime, &exitTime, &kernelTime, &userTime)
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+	ch <- MustNewConstMetric(c.startTime, GaugeValue, float64(startTime.Nanoseconds()/1e9))
+	ch <- MustNewConstMetric(c.cpuTotal, CounterValue, fileTimeToSeconds(kernelTime)+fileTimeToSeconds(userTime))
+
+	mem, err := getProcessMemoryInfo(h)
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+	ch <- MustNewConstMetric(c.vsize, GaugeValue, float64(mem.PrivateUsage))
+	ch <- MustNewConstMetric(c.rss, GaugeValue, float64(mem.WorkingSetSize))
+
+	handles, err := getProcessHandleCount(h)
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+	ch <- MustNewConstMetric(c.openFDs, GaugeValue, float64(handles))
+	ch <- MustNewConstMetric(c.maxFDs, GaugeValue, float64(16*1024*1024)) // Windows has a hard-coded max limit, not per-process.
+}
+
+func fileTimeToSeconds(ft windows.Filetime) float64 {
+	return float64(uint64(ft.HighDateTime)<<32+uint64(ft.LowDateTime)) / 1e7
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator.go

@@ -0,0 +1,370 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package promhttp
+
+import (
+	"bufio"
+	"io"
+	"net"
+	"net/http"
+)
+
+const (
+	closeNotifier = 1 << iota
+	flusher
+	hijacker
+	readerFrom
+	pusher
+)
+
+type delegator interface {
+	http.ResponseWriter
+
+	Status() int
+	Written() int64
+}
+
+type responseWriterDelegator struct {
+	http.ResponseWriter
+
+	status             int
+	written            int64
+	wroteHeader        bool
+	observeWriteHeader func(int)
+}
+
+func (r *responseWriterDelegator) Status() int {
+	return r.status
+}
+
+func (r *responseWriterDelegator) Written() int64 {
+	return r.written
+}
+
+func (r *responseWriterDelegator) WriteHeader(code int) {
+	if r.observeWriteHeader != nil && !r.wroteHeader {
+		// Only call observeWriteHeader for the 1st time. It's a bug if
+		// WriteHeader is called more than once, but we want to protect
+		// against it here. Note that we still delegate the WriteHeader
+		// to the original ResponseWriter to not mask the bug from it.
+		r.observeWriteHeader(code)
+	}
+	r.status = code
+	r.wroteHeader = true
+	r.ResponseWriter.WriteHeader(code)
+}
+
+func (r *responseWriterDelegator) Write(b []byte) (int, error) {
+	// If applicable, call WriteHeader here so that observeWriteHeader is
+	// handled appropriately.
+	if !r.wroteHeader {
+		r.WriteHeader(http.StatusOK)
+	}
+	n, err := r.ResponseWriter.Write(b)
+	r.written += int64(n)
+	return n, err
+}
+
+type closeNotifierDelegator struct{ *responseWriterDelegator }
+type flusherDelegator struct{ *responseWriterDelegator }
+type hijackerDelegator struct{ *responseWriterDelegator }
+type readerFromDelegator struct{ *responseWriterDelegator }
+type pusherDelegator struct{ *responseWriterDelegator }
+
+func (d closeNotifierDelegator) CloseNotify() <-chan bool {
+	//lint:ignore SA1019 http.CloseNotifier is deprecated but we don't want to
+	//remove support from client_golang yet.
+	return d.ResponseWriter.(http.CloseNotifier).CloseNotify()
+}
+func (d flusherDelegator) Flush() {
+	// If applicable, call WriteHeader here so that observeWriteHeader is
+	// handled appropriately.
+	if !d.wroteHeader {
+		d.WriteHeader(http.StatusOK)
+	}
+	d.ResponseWriter.(http.Flusher).Flush()
+}
+func (d hijackerDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	return d.ResponseWriter.(http.Hijacker).Hijack()
+}
+func (d readerFromDelegator) ReadFrom(re io.Reader) (int64, error) {
+	// If applicable, call WriteHeader here so that observeWriteHeader is
+	// handled appropriately.
+	if !d.wroteHeader {
+		d.WriteHeader(http.StatusOK)
+	}
+	n, err := d.ResponseWriter.(io.ReaderFrom).ReadFrom(re)
+	d.written += n
+	return n, err
+}
+func (d pusherDelegator) Push(target string, opts *http.PushOptions) error {
+	return d.ResponseWriter.(http.Pusher).Push(target, opts)
+}
+
+var pickDelegator = make([]func(*responseWriterDelegator) delegator, 32)
+
+func init() {
+	// TODO(beorn7): Code generation would help here.
+	pickDelegator[0] = func(d *responseWriterDelegator) delegator { // 0
+		return d
+	}
+	pickDelegator[closeNotifier] = func(d *responseWriterDelegator) delegator { // 1
+		return closeNotifierDelegator{d}
+	}
+	pickDelegator[flusher] = func(d *responseWriterDelegator) delegator { // 2
+		return flusherDelegator{d}
+	}
+	pickDelegator[flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 3
+		return struct {
+			*responseWriterDelegator
+			http.Flusher
+			http.CloseNotifier
+		}{d, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[hijacker] = func(d *responseWriterDelegator) delegator { // 4
+		return hijackerDelegator{d}
+	}
+	pickDelegator[hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 5
+		return struct {
+			*responseWriterDelegator
+			http.Hijacker
+			http.CloseNotifier
+		}{d, hijackerDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 6
+		return struct {
+			*responseWriterDelegator
+			http.Hijacker
+			http.Flusher
+		}{d, hijackerDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 7
+		return struct {
+			*responseWriterDelegator
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[readerFrom] = func(d *responseWriterDelegator) delegator { // 8
+		return readerFromDelegator{d}
+	}
+	pickDelegator[readerFrom+closeNotifier] = func(d *responseWriterDelegator) delegator { // 9
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.CloseNotifier
+		}{d, readerFromDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[readerFrom+flusher] = func(d *responseWriterDelegator) delegator { // 10
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Flusher
+		}{d, readerFromDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[readerFrom+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 11
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Flusher
+			http.CloseNotifier
+		}{d, readerFromDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[readerFrom+hijacker] = func(d *responseWriterDelegator) delegator { // 12
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Hijacker
+		}{d, readerFromDelegator{d}, hijackerDelegator{d}}
+	}
+	pickDelegator[readerFrom+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 13
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Hijacker
+			http.CloseNotifier
+		}{d, readerFromDelegator{d}, hijackerDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[readerFrom+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 14
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+		}{d, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[readerFrom+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 15
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher] = func(d *responseWriterDelegator) delegator { // 16
+		return pusherDelegator{d}
+	}
+	pickDelegator[pusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 17
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+flusher] = func(d *responseWriterDelegator) delegator { // 18
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Flusher
+		}{d, pusherDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[pusher+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 19
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Flusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker] = func(d *responseWriterDelegator) delegator { // 20
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+		}{d, pusherDelegator{d}, hijackerDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 21
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, hijackerDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 22
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.Flusher
+		}{d, pusherDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { //23
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom] = func(d *responseWriterDelegator) delegator { // 24
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+		}{d, pusherDelegator{d}, readerFromDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+closeNotifier] = func(d *responseWriterDelegator) delegator { // 25
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+flusher] = func(d *responseWriterDelegator) delegator { // 26
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Flusher
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 27
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Flusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker] = func(d *responseWriterDelegator) delegator { // 28
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 29
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 30
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 31
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+}
+
+func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator {
+	d := &responseWriterDelegator{
+		ResponseWriter:     w,
+		observeWriteHeader: observeWriteHeaderFunc,
+	}
+
+	id := 0
+	//lint:ignore SA1019 http.CloseNotifier is deprecated but we don't want to
+	//remove support from client_golang yet.
+	if _, ok := w.(http.CloseNotifier); ok {
+		id += closeNotifier
+	}
+	if _, ok := w.(http.Flusher); ok {
+		id += flusher
+	}
+	if _, ok := w.(http.Hijacker); ok {
+		id += hijacker
+	}
+	if _, ok := w.(io.ReaderFrom); ok {
+		id += readerFrom
+	}
+	if _, ok := w.(http.Pusher); ok {
+		id += pusher
+	}
+
+	return pickDelegator[id](d)
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go

@@ -0,0 +1,379 @@
+// Copyright 2016 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package promhttp provides tooling around HTTP servers and clients.
+//
+// First, the package allows the creation of http.Handler instances to expose
+// Prometheus metrics via HTTP. promhttp.Handler acts on the
+// prometheus.DefaultGatherer. With HandlerFor, you can create a handler for a
+// custom registry or anything that implements the Gatherer interface. It also
+// allows the creation of handlers that act differently on errors or allow to
+// log errors.
+//
+// Second, the package provides tooling to instrument instances of http.Handler
+// via middleware. Middleware wrappers follow the naming scheme
+// InstrumentHandlerX, where X describes the intended use of the middleware.
+// See each function's doc comment for specific details.
+//
+// Finally, the package allows for an http.RoundTripper to be instrumented via
+// middleware. Middleware wrappers follow the naming scheme
+// InstrumentRoundTripperX, where X describes the intended use of the
+// middleware. See each function's doc comment for specific details.
+package promhttp
+
+import (
+	"compress/gzip"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/prometheus/common/expfmt"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const (
+	contentTypeHeader     = "Content-Type"
+	contentEncodingHeader = "Content-Encoding"
+	acceptEncodingHeader  = "Accept-Encoding"
+)
+
+var gzipPool = sync.Pool{
+	New: func() interface{} {
+		return gzip.NewWriter(nil)
+	},
+}
+
+// Handler returns an http.Handler for the prometheus.DefaultGatherer, using
+// default HandlerOpts, i.e. it reports the first error as an HTTP error, it has
+// no error logging, and it applies compression if requested by the client.
+//
+// The returned http.Handler is already instrumented using the
+// InstrumentMetricHandler function and the prometheus.DefaultRegisterer. If you
+// create multiple http.Handlers by separate calls of the Handler function, the
+// metrics used for instrumentation will be shared between them, providing
+// global scrape counts.
+//
+// This function is meant to cover the bulk of basic use cases. If you are doing
+// anything that requires more customization (including using a non-default
+// Gatherer, different instrumentation, and non-default HandlerOpts), use the
+// HandlerFor function. See there for details.
+func Handler() http.Handler {
+	return InstrumentMetricHandler(
+		prometheus.DefaultRegisterer, HandlerFor(prometheus.DefaultGatherer, HandlerOpts{}),
+	)
+}
+
+// HandlerFor returns an uninstrumented http.Handler for the provided
+// Gatherer. The behavior of the Handler is defined by the provided
+// HandlerOpts. Thus, HandlerFor is useful to create http.Handlers for custom
+// Gatherers, with non-default HandlerOpts, and/or with custom (or no)
+// instrumentation. Use the InstrumentMetricHandler function to apply the same
+// kind of instrumentation as it is used by the Handler function.
+func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
+	var (
+		inFlightSem chan struct{}
+		errCnt      = prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Name: "promhttp_metric_handler_errors_total",
+				Help: "Total number of internal errors encountered by the promhttp metric handler.",
+			},
+			[]string{"cause"},
+		)
+	)
+
+	if opts.MaxRequestsInFlight > 0 {
+		inFlightSem = make(chan struct{}, opts.MaxRequestsInFlight)
+	}
+	if opts.Registry != nil {
+		// Initialize all possibilites that can occur below.
+		errCnt.WithLabelValues("gathering")
+		errCnt.WithLabelValues("encoding")
+		if err := opts.Registry.Register(errCnt); err != nil {
+			if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+				errCnt = are.ExistingCollector.(*prometheus.CounterVec)
+			} else {
+				panic(err)
+			}
+		}
+	}
+
+	h := http.HandlerFunc(func(rsp http.ResponseWriter, req *http.Request) {
+		if inFlightSem != nil {
+			select {
+			case inFlightSem <- struct{}{}: // All good, carry on.
+				defer func() { <-inFlightSem }()
+			default:
+				http.Error(rsp, fmt.Sprintf(
+					"Limit of concurrent requests reached (%d), try again later.", opts.MaxRequestsInFlight,
+				), http.StatusServiceUnavailable)
+				return
+			}
+		}
+		mfs, err := reg.Gather()
+		if err != nil {
+			if opts.ErrorLog != nil {
+				opts.ErrorLog.Println("error gathering metrics:", err)
+			}
+			errCnt.WithLabelValues("gathering").Inc()
+			switch opts.ErrorHandling {
+			case PanicOnError:
+				panic(err)
+			case ContinueOnError:
+				if len(mfs) == 0 {
+					// Still report the error if no metrics have been gathered.
+					httpError(rsp, err)
+					return
+				}
+			case HTTPErrorOnError:
+				httpError(rsp, err)
+				return
+			}
+		}
+
+		var contentType expfmt.Format
+		if opts.EnableOpenMetrics {
+			contentType = expfmt.NegotiateIncludingOpenMetrics(req.Header)
+		} else {
+			contentType = expfmt.Negotiate(req.Header)
+		}
+		header := rsp.Header()
+		header.Set(contentTypeHeader, string(contentType))
+
+		w := io.Writer(rsp)
+		if !opts.DisableCompression && gzipAccepted(req.Header) {
+			header.Set(contentEncodingHeader, "gzip")
+			gz := gzipPool.Get().(*gzip.Writer)
+			defer gzipPool.Put(gz)
+
+			gz.Reset(w)
+			defer gz.Close()
+
+			w = gz
+		}
+
+		enc := expfmt.NewEncoder(w, contentType)
+
+		// handleError handles the error according to opts.ErrorHandling
+		// and returns true if we have to abort after the handling.
+		handleError := func(err error) bool {
+			if err == nil {
+				return false
+			}
+			if opts.ErrorLog != nil {
+				opts.ErrorLog.Println("error encoding and sending metric family:", err)
+			}
+			errCnt.WithLabelValues("encoding").Inc()
+			switch opts.ErrorHandling {
+			case PanicOnError:
+				panic(err)
+			case HTTPErrorOnError:
+				// We cannot really send an HTTP error at this
+				// point because we most likely have written
+				// something to rsp already. But at least we can
+				// stop sending.
+				return true
+			}
+			// Do nothing in all other cases, including ContinueOnError.
+			return false
+		}
+
+		for _, mf := range mfs {
+			if handleError(enc.Encode(mf)) {
+				return
+			}
+		}
+		if closer, ok := enc.(expfmt.Closer); ok {
+			// This in particular takes care of the final "# EOF\n" line for OpenMetrics.
+			if handleError(closer.Close()) {
+				return
+			}
+		}
+	})
+
+	if opts.Timeout <= 0 {
+		return h
+	}
+	return http.TimeoutHandler(h, opts.Timeout, fmt.Sprintf(
+		"Exceeded configured timeout of %v.\n",
+		opts.Timeout,
+	))
+}
+
+// InstrumentMetricHandler is usually used with an http.Handler returned by the
+// HandlerFor function. It instruments the provided http.Handler with two
+// metrics: A counter vector "promhttp_metric_handler_requests_total" to count
+// scrapes partitioned by HTTP status code, and a gauge
+// "promhttp_metric_handler_requests_in_flight" to track the number of
+// simultaneous scrapes. This function idempotently registers collectors for
+// both metrics with the provided Registerer. It panics if the registration
+// fails. The provided metrics are useful to see how many scrapes hit the
+// monitored target (which could be from different Prometheus servers or other
+// scrapers), and how often they overlap (which would result in more than one
+// scrape in flight at the same time). Note that the scrapes-in-flight gauge
+// will contain the scrape by which it is exposed, while the scrape counter will
+// only get incremented after the scrape is complete (as only then the status
+// code is known). For tracking scrape durations, use the
+// "scrape_duration_seconds" gauge created by the Prometheus server upon each
+// scrape.
+func InstrumentMetricHandler(reg prometheus.Registerer, handler http.Handler) http.Handler {
+	cnt := prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "promhttp_metric_handler_requests_total",
+			Help: "Total number of scrapes by HTTP status code.",
+		},
+		[]string{"code"},
+	)
+	// Initialize the most likely HTTP status codes.
+	cnt.WithLabelValues("200")
+	cnt.WithLabelValues("500")
+	cnt.WithLabelValues("503")
+	if err := reg.Register(cnt); err != nil {
+		if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+			cnt = are.ExistingCollector.(*prometheus.CounterVec)
+		} else {
+			panic(err)
+		}
+	}
+
+	gge := prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "promhttp_metric_handler_requests_in_flight",
+		Help: "Current number of scrapes being served.",
+	})
+	if err := reg.Register(gge); err != nil {
+		if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+			gge = are.ExistingCollector.(prometheus.Gauge)
+		} else {
+			panic(err)
+		}
+	}
+
+	return InstrumentHandlerCounter(cnt, InstrumentHandlerInFlight(gge, handler))
+}
+
+// HandlerErrorHandling defines how a Handler serving metrics will handle
+// errors.
+type HandlerErrorHandling int
+
+// These constants cause handlers serving metrics to behave as described if
+// errors are encountered.
+const (
+	// Serve an HTTP status code 500 upon the first error
+	// encountered. Report the error message in the body. Note that HTTP
+	// errors cannot be served anymore once the beginning of a regular
+	// payload has been sent. Thus, in the (unlikely) case that encoding the
+	// payload into the negotiated wire format fails, serving the response
+	// will simply be aborted. Set an ErrorLog in HandlerOpts to detect
+	// those errors.
+	HTTPErrorOnError HandlerErrorHandling = iota
+	// Ignore errors and try to serve as many metrics as possible.  However,
+	// if no metrics can be served, serve an HTTP status code 500 and the
+	// last error message in the body. Only use this in deliberate "best
+	// effort" metrics collection scenarios. In this case, it is highly
+	// recommended to provide other means of detecting errors: By setting an
+	// ErrorLog in HandlerOpts, the errors are logged. By providing a
+	// Registry in HandlerOpts, the exposed metrics include an error counter
+	// "promhttp_metric_handler_errors_total", which can be used for
+	// alerts.
+	ContinueOnError
+	// Panic upon the first error encountered (useful for "crash only" apps).
+	PanicOnError
+)
+
+// Logger is the minimal interface HandlerOpts needs for logging. Note that
+// log.Logger from the standard library implements this interface, and it is
+// easy to implement by custom loggers, if they don't do so already anyway.
+type Logger interface {
+	Println(v ...interface{})
+}
+
+// HandlerOpts specifies options how to serve metrics via an http.Handler. The
+// zero value of HandlerOpts is a reasonable default.
+type HandlerOpts struct {
+	// ErrorLog specifies an optional logger for errors collecting and
+	// serving metrics. If nil, errors are not logged at all.
+	ErrorLog Logger
+	// ErrorHandling defines how errors are handled. Note that errors are
+	// logged regardless of the configured ErrorHandling provided ErrorLog
+	// is not nil.
+	ErrorHandling HandlerErrorHandling
+	// If Registry is not nil, it is used to register a metric
+	// "promhttp_metric_handler_errors_total", partitioned by "cause". A
+	// failed registration causes a panic. Note that this error counter is
+	// different from the instrumentation you get from the various
+	// InstrumentHandler... helpers. It counts errors that don't necessarily
+	// result in a non-2xx HTTP status code. There are two typical cases:
+	// (1) Encoding errors that only happen after streaming of the HTTP body
+	// has already started (and the status code 200 has been sent). This
+	// should only happen with custom collectors. (2) Collection errors with
+	// no effect on the HTTP status code because ErrorHandling is set to
+	// ContinueOnError.
+	Registry prometheus.Registerer
+	// If DisableCompression is true, the handler will never compress the
+	// response, even if requested by the client.
+	DisableCompression bool
+	// The number of concurrent HTTP requests is limited to
+	// MaxRequestsInFlight. Additional requests are responded to with 503
+	// Service Unavailable and a suitable message in the body. If
+	// MaxRequestsInFlight is 0 or negative, no limit is applied.
+	MaxRequestsInFlight int
+	// If handling a request takes longer than Timeout, it is responded to
+	// with 503 ServiceUnavailable and a suitable Message. No timeout is
+	// applied if Timeout is 0 or negative. Note that with the current
+	// implementation, reaching the timeout simply ends the HTTP requests as
+	// described above (and even that only if sending of the body hasn't
+	// started yet), while the bulk work of gathering all the metrics keeps
+	// running in the background (with the eventual result to be thrown
+	// away). Until the implementation is improved, it is recommended to
+	// implement a separate timeout in potentially slow Collectors.
+	Timeout time.Duration
+	// If true, the experimental OpenMetrics encoding is added to the
+	// possible options during content negotiation. Note that Prometheus
+	// 2.5.0+ will negotiate OpenMetrics as first priority. OpenMetrics is
+	// the only way to transmit exemplars. However, the move to OpenMetrics
+	// is not completely transparent. Most notably, the values of "quantile"
+	// labels of Summaries and "le" labels of Histograms are formatted with
+	// a trailing ".0" if they would otherwise look like integer numbers
+	// (which changes the identity of the resulting series on the Prometheus
+	// server).
+	EnableOpenMetrics bool
+}
+
+// gzipAccepted returns whether the client will accept gzip-encoded content.
+func gzipAccepted(header http.Header) bool {
+	a := header.Get(acceptEncodingHeader)
+	parts := strings.Split(a, ",")
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+		if part == "gzip" || strings.HasPrefix(part, "gzip;") {
+			return true
+		}
+	}
+	return false
+}
+
+// httpError removes any content-encoding header and then calls http.Error with
+// the provided error and http.StatusInternalServerError. Error contents is
+// supposed to be uncompressed plain text. Same as with a plain http.Error, this
+// must not be called if the header or any payload has already been sent.
+func httpError(rsp http.ResponseWriter, err error) {
+	rsp.Header().Del(contentEncodingHeader)
+	http.Error(
+		rsp,
+		"An error has occurred while serving metrics:\n\n"+err.Error(),
+		http.StatusInternalServerError,
+	)
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_client.go

@@ -0,0 +1,219 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package promhttp
+
+import (
+	"crypto/tls"
+	"net/http"
+	"net/http/httptrace"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// The RoundTripperFunc type is an adapter to allow the use of ordinary
+// functions as RoundTrippers. If f is a function with the appropriate
+// signature, RountTripperFunc(f) is a RoundTripper that calls f.
+type RoundTripperFunc func(req *http.Request) (*http.Response, error)
+
+// RoundTrip implements the RoundTripper interface.
+func (rt RoundTripperFunc) RoundTrip(r *http.Request) (*http.Response, error) {
+	return rt(r)
+}
+
+// InstrumentRoundTripperInFlight is a middleware that wraps the provided
+// http.RoundTripper. It sets the provided prometheus.Gauge to the number of
+// requests currently handled by the wrapped http.RoundTripper.
+//
+// See the example for ExampleInstrumentRoundTripperDuration for example usage.
+func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripper) RoundTripperFunc {
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		gauge.Inc()
+		defer gauge.Dec()
+		return next.RoundTrip(r)
+	})
+}
+
+// InstrumentRoundTripperCounter is a middleware that wraps the provided
+// http.RoundTripper to observe the request result with the provided CounterVec.
+// The CounterVec must have zero, one, or two non-const non-curried labels. For
+// those, the only allowed label names are "code" and "method". The function
+// panics otherwise. Partitioning of the CounterVec happens by HTTP status code
+// and/or HTTP method if the respective instance label names are present in the
+// CounterVec. For unpartitioned counting, use a CounterVec with zero labels.
+//
+// If the wrapped RoundTripper panics or returns a non-nil error, the Counter
+// is not incremented.
+//
+// See the example for ExampleInstrumentRoundTripperDuration for example usage.
+func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.RoundTripper) RoundTripperFunc {
+	code, method := checkLabels(counter)
+
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		resp, err := next.RoundTrip(r)
+		if err == nil {
+			counter.With(labels(code, method, r.Method, resp.StatusCode)).Inc()
+		}
+		return resp, err
+	})
+}
+
+// InstrumentRoundTripperDuration is a middleware that wraps the provided
+// http.RoundTripper to observe the request duration with the provided
+// ObserverVec.  The ObserverVec must have zero, one, or two non-const
+// non-curried labels. For those, the only allowed label names are "code" and
+// "method". The function panics otherwise. The Observe method of the Observer
+// in the ObserverVec is called with the request duration in
+// seconds. Partitioning happens by HTTP status code and/or HTTP method if the
+// respective instance label names are present in the ObserverVec. For
+// unpartitioned observations, use an ObserverVec with zero labels. Note that
+// partitioning of Histograms is expensive and should be used judiciously.
+//
+// If the wrapped RoundTripper panics or returns a non-nil error, no values are
+// reported.
+//
+// Note that this method is only guaranteed to never observe negative durations
+// if used with Go1.9+.
+func InstrumentRoundTripperDuration(obs prometheus.ObserverVec, next http.RoundTripper) RoundTripperFunc {
+	code, method := checkLabels(obs)
+
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		start := time.Now()
+		resp, err := next.RoundTrip(r)
+		if err == nil {
+			obs.With(labels(code, method, r.Method, resp.StatusCode)).Observe(time.Since(start).Seconds())
+		}
+		return resp, err
+	})
+}
+
+// InstrumentTrace is used to offer flexibility in instrumenting the available
+// httptrace.ClientTrace hook functions. Each function is passed a float64
+// representing the time in seconds since the start of the http request. A user
+// may choose to use separately buckets Histograms, or implement custom
+// instance labels on a per function basis.
+type InstrumentTrace struct {
+	GotConn              func(float64)
+	PutIdleConn          func(float64)
+	GotFirstResponseByte func(float64)
+	Got100Continue       func(float64)
+	DNSStart             func(float64)
+	DNSDone              func(float64)
+	ConnectStart         func(float64)
+	ConnectDone          func(float64)
+	TLSHandshakeStart    func(float64)
+	TLSHandshakeDone     func(float64)
+	WroteHeaders         func(float64)
+	Wait100Continue      func(float64)
+	WroteRequest         func(float64)
+}
+
+// InstrumentRoundTripperTrace is a middleware that wraps the provided
+// RoundTripper and reports times to hook functions provided in the
+// InstrumentTrace struct. Hook functions that are not present in the provided
+// InstrumentTrace struct are ignored. Times reported to the hook functions are
+// time since the start of the request. Only with Go1.9+, those times are
+// guaranteed to never be negative. (Earlier Go versions are not using a
+// monotonic clock.) Note that partitioning of Histograms is expensive and
+// should be used judiciously.
+//
+// For hook functions that receive an error as an argument, no observations are
+// made in the event of a non-nil error value.
+//
+// See the example for ExampleInstrumentRoundTripperDuration for example usage.
+func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) RoundTripperFunc {
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		start := time.Now()
+
+		trace := &httptrace.ClientTrace{
+			GotConn: func(_ httptrace.GotConnInfo) {
+				if it.GotConn != nil {
+					it.GotConn(time.Since(start).Seconds())
+				}
+			},
+			PutIdleConn: func(err error) {
+				if err != nil {
+					return
+				}
+				if it.PutIdleConn != nil {
+					it.PutIdleConn(time.Since(start).Seconds())
+				}
+			},
+			DNSStart: func(_ httptrace.DNSStartInfo) {
+				if it.DNSStart != nil {
+					it.DNSStart(time.Since(start).Seconds())
+				}
+			},
+			DNSDone: func(_ httptrace.DNSDoneInfo) {
+				if it.DNSDone != nil {
+					it.DNSDone(time.Since(start).Seconds())
+				}
+			},
+			ConnectStart: func(_, _ string) {
+				if it.ConnectStart != nil {
+					it.ConnectStart(time.Since(start).Seconds())
+				}
+			},
+			ConnectDone: func(_, _ string, err error) {
+				if err != nil {
+					return
+				}
+				if it.ConnectDone != nil {
+					it.ConnectDone(time.Since(start).Seconds())
+				}
+			},
+			GotFirstResponseByte: func() {
+				if it.GotFirstResponseByte != nil {
+					it.GotFirstResponseByte(time.Since(start).Seconds())
+				}
+			},
+			Got100Continue: func() {
+				if it.Got100Continue != nil {
+					it.Got100Continue(time.Since(start).Seconds())
+				}
+			},
+			TLSHandshakeStart: func() {
+				if it.TLSHandshakeStart != nil {
+					it.TLSHandshakeStart(time.Since(start).Seconds())
+				}
+			},
+			TLSHandshakeDone: func(_ tls.ConnectionState, err error) {
+				if err != nil {
+					return
+				}
+				if it.TLSHandshakeDone != nil {
+					it.TLSHandshakeDone(time.Since(start).Seconds())
+				}
+			},
+			WroteHeaders: func() {
+				if it.WroteHeaders != nil {
+					it.WroteHeaders(time.Since(start).Seconds())
+				}
+			},
+			Wait100Continue: func() {
+				if it.Wait100Continue != nil {
+					it.Wait100Continue(time.Since(start).Seconds())
+				}
+			},
+			WroteRequest: func(_ httptrace.WroteRequestInfo) {
+				if it.WroteRequest != nil {
+					it.WroteRequest(time.Since(start).Seconds())
+				}
+			},
+		}
+		r = r.WithContext(httptrace.WithClientTrace(r.Context(), trace))
+
+		return next.RoundTrip(r)
+	})
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_server.go

@@ -0,0 +1,447 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package promhttp
+
+import (
+	"errors"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	dto "github.com/prometheus/client_model/go"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// magicString is used for the hacky label test in checkLabels. Remove once fixed.
+const magicString = "zZgWfBxLqvG8kc8IMv3POi2Bb0tZI3vAnBx+gBaFi9FyPzB/CzKUer1yufDa"
+
+// InstrumentHandlerInFlight is a middleware that wraps the provided
+// http.Handler. It sets the provided prometheus.Gauge to the number of
+// requests currently handled by the wrapped http.Handler.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerInFlight(g prometheus.Gauge, next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		g.Inc()
+		defer g.Dec()
+		next.ServeHTTP(w, r)
+	})
+}
+
+// InstrumentHandlerDuration is a middleware that wraps the provided
+// http.Handler to observe the request duration with the provided ObserverVec.
+// The ObserverVec must have zero, one, or two non-const non-curried labels. For
+// those, the only allowed label names are "code" and "method". The function
+// panics otherwise. The Observe method of the Observer in the ObserverVec is
+// called with the request duration in seconds. Partitioning happens by HTTP
+// status code and/or HTTP method if the respective instance label names are
+// present in the ObserverVec. For unpartitioned observations, use an
+// ObserverVec with zero labels. Note that partitioning of Histograms is
+// expensive and should be used judiciously.
+//
+// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
+//
+// If the wrapped Handler panics, no values are reported.
+//
+// Note that this method is only guaranteed to never observe negative durations
+// if used with Go1.9+.
+func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler) http.HandlerFunc {
+	code, method := checkLabels(obs)
+
+	if code {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			now := time.Now()
+			d := newDelegator(w, nil)
+			next.ServeHTTP(d, r)
+
+			obs.With(labels(code, method, r.Method, d.Status())).Observe(time.Since(now).Seconds())
+		})
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		now := time.Now()
+		next.ServeHTTP(w, r)
+		obs.With(labels(code, method, r.Method, 0)).Observe(time.Since(now).Seconds())
+	})
+}
+
+// InstrumentHandlerCounter is a middleware that wraps the provided http.Handler
+// to observe the request result with the provided CounterVec.  The CounterVec
+// must have zero, one, or two non-const non-curried labels. For those, the only
+// allowed label names are "code" and "method". The function panics
+// otherwise. Partitioning of the CounterVec happens by HTTP status code and/or
+// HTTP method if the respective instance label names are present in the
+// CounterVec. For unpartitioned counting, use a CounterVec with zero labels.
+//
+// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
+//
+// If the wrapped Handler panics, the Counter is not incremented.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler) http.HandlerFunc {
+	code, method := checkLabels(counter)
+
+	if code {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			d := newDelegator(w, nil)
+			next.ServeHTTP(d, r)
+			counter.With(labels(code, method, r.Method, d.Status())).Inc()
+		})
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		next.ServeHTTP(w, r)
+		counter.With(labels(code, method, r.Method, 0)).Inc()
+	})
+}
+
+// InstrumentHandlerTimeToWriteHeader is a middleware that wraps the provided
+// http.Handler to observe with the provided ObserverVec the request duration
+// until the response headers are written. The ObserverVec must have zero, one,
+// or two non-const non-curried labels. For those, the only allowed label names
+// are "code" and "method". The function panics otherwise. The Observe method of
+// the Observer in the ObserverVec is called with the request duration in
+// seconds. Partitioning happens by HTTP status code and/or HTTP method if the
+// respective instance label names are present in the ObserverVec. For
+// unpartitioned observations, use an ObserverVec with zero labels. Note that
+// partitioning of Histograms is expensive and should be used judiciously.
+//
+// If the wrapped Handler panics before calling WriteHeader, no value is
+// reported.
+//
+// Note that this method is only guaranteed to never observe negative durations
+// if used with Go1.9+.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerTimeToWriteHeader(obs prometheus.ObserverVec, next http.Handler) http.HandlerFunc {
+	code, method := checkLabels(obs)
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		now := time.Now()
+		d := newDelegator(w, func(status int) {
+			obs.With(labels(code, method, r.Method, status)).Observe(time.Since(now).Seconds())
+		})
+		next.ServeHTTP(d, r)
+	})
+}
+
+// InstrumentHandlerRequestSize is a middleware that wraps the provided
+// http.Handler to observe the request size with the provided ObserverVec.  The
+// ObserverVec must have zero, one, or two non-const non-curried labels. For
+// those, the only allowed label names are "code" and "method". The function
+// panics otherwise. The Observe method of the Observer in the ObserverVec is
+// called with the request size in bytes. Partitioning happens by HTTP status
+// code and/or HTTP method if the respective instance label names are present in
+// the ObserverVec. For unpartitioned observations, use an ObserverVec with zero
+// labels. Note that partitioning of Histograms is expensive and should be used
+// judiciously.
+//
+// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
+//
+// If the wrapped Handler panics, no values are reported.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerRequestSize(obs prometheus.ObserverVec, next http.Handler) http.HandlerFunc {
+	code, method := checkLabels(obs)
+
+	if code {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			d := newDelegator(w, nil)
+			next.ServeHTTP(d, r)
+			size := computeApproximateRequestSize(r)
+			obs.With(labels(code, method, r.Method, d.Status())).Observe(float64(size))
+		})
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		next.ServeHTTP(w, r)
+		size := computeApproximateRequestSize(r)
+		obs.With(labels(code, method, r.Method, 0)).Observe(float64(size))
+	})
+}
+
+// InstrumentHandlerResponseSize is a middleware that wraps the provided
+// http.Handler to observe the response size with the provided ObserverVec.  The
+// ObserverVec must have zero, one, or two non-const non-curried labels. For
+// those, the only allowed label names are "code" and "method". The function
+// panics otherwise. The Observe method of the Observer in the ObserverVec is
+// called with the response size in bytes. Partitioning happens by HTTP status
+// code and/or HTTP method if the respective instance label names are present in
+// the ObserverVec. For unpartitioned observations, use an ObserverVec with zero
+// labels. Note that partitioning of Histograms is expensive and should be used
+// judiciously.
+//
+// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
+//
+// If the wrapped Handler panics, no values are reported.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerResponseSize(obs prometheus.ObserverVec, next http.Handler) http.Handler {
+	code, method := checkLabels(obs)
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		d := newDelegator(w, nil)
+		next.ServeHTTP(d, r)
+		obs.With(labels(code, method, r.Method, d.Status())).Observe(float64(d.Written()))
+	})
+}
+
+func checkLabels(c prometheus.Collector) (code bool, method bool) {
+	// TODO(beorn7): Remove this hacky way to check for instance labels
+	// once Descriptors can have their dimensionality queried.
+	var (
+		desc *prometheus.Desc
+		m    prometheus.Metric
+		pm   dto.Metric
+		lvs  []string
+	)
+
+	// Get the Desc from the Collector.
+	descc := make(chan *prometheus.Desc, 1)
+	c.Describe(descc)
+
+	select {
+	case desc = <-descc:
+	default:
+		panic("no description provided by collector")
+	}
+	select {
+	case <-descc:
+		panic("more than one description provided by collector")
+	default:
+	}
+
+	close(descc)
+
+	// Create a ConstMetric with the Desc. Since we don't know how many
+	// variable labels there are, try for as long as it needs.
+	for err := errors.New("dummy"); err != nil; lvs = append(lvs, magicString) {
+		m, err = prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, lvs...)
+	}
+
+	// Write out the metric into a proto message and look at the labels.
+	// If the value is not the magicString, it is a constLabel, which doesn't interest us.
+	// If the label is curried, it doesn't interest us.
+	// In all other cases, only "code" or "method" is allowed.
+	if err := m.Write(&pm); err != nil {
+		panic("error checking metric for labels")
+	}
+	for _, label := range pm.Label {
+		name, value := label.GetName(), label.GetValue()
+		if value != magicString || isLabelCurried(c, name) {
+			continue
+		}
+		switch name {
+		case "code":
+			code = true
+		case "method":
+			method = true
+		default:
+			panic("metric partitioned with non-supported labels")
+		}
+	}
+	return
+}
+
+func isLabelCurried(c prometheus.Collector, label string) bool {
+	// This is even hackier than the label test above.
+	// We essentially try to curry again and see if it works.
+	// But for that, we need to type-convert to the two
+	// types we use here, ObserverVec or *CounterVec.
+	switch v := c.(type) {
+	case *prometheus.CounterVec:
+		if _, err := v.CurryWith(prometheus.Labels{label: "dummy"}); err == nil {
+			return false
+		}
+	case prometheus.ObserverVec:
+		if _, err := v.CurryWith(prometheus.Labels{label: "dummy"}); err == nil {
+			return false
+		}
+	default:
+		panic("unsupported metric vec type")
+	}
+	return true
+}
+
+// emptyLabels is a one-time allocation for non-partitioned metrics to avoid
+// unnecessary allocations on each request.
+var emptyLabels = prometheus.Labels{}
+
+func labels(code, method bool, reqMethod string, status int) prometheus.Labels {
+	if !(code || method) {
+		return emptyLabels
+	}
+	labels := prometheus.Labels{}
+
+	if code {
+		labels["code"] = sanitizeCode(status)
+	}
+	if method {
+		labels["method"] = sanitizeMethod(reqMethod)
+	}
+
+	return labels
+}
+
+func computeApproximateRequestSize(r *http.Request) int {
+	s := 0
+	if r.URL != nil {
+		s += len(r.URL.String())
+	}
+
+	s += len(r.Method)
+	s += len(r.Proto)
+	for name, values := range r.Header {
+		s += len(name)
+		for _, value := range values {
+			s += len(value)
+		}
+	}
+	s += len(r.Host)
+
+	// N.B. r.Form and r.MultipartForm are assumed to be included in r.URL.
+
+	if r.ContentLength != -1 {
+		s += int(r.ContentLength)
+	}
+	return s
+}
+
+func sanitizeMethod(m string) string {
+	switch m {
+	case "GET", "get":
+		return "get"
+	case "PUT", "put":
+		return "put"
+	case "HEAD", "head":
+		return "head"
+	case "POST", "post":
+		return "post"
+	case "DELETE", "delete":
+		return "delete"
+	case "CONNECT", "connect":
+		return "connect"
+	case "OPTIONS", "options":
+		return "options"
+	case "NOTIFY", "notify":
+		return "notify"
+	default:
+		return strings.ToLower(m)
+	}
+}
+
+// If the wrapped http.Handler has not set a status code, i.e. the value is
+// currently 0, santizeCode will return 200, for consistency with behavior in
+// the stdlib.
+func sanitizeCode(s int) string {
+	switch s {
+	case 100:
+		return "100"
+	case 101:
+		return "101"
+
+	case 200, 0:
+		return "200"
+	case 201:
+		return "201"
+	case 202:
+		return "202"
+	case 203:
+		return "203"
+	case 204:
+		return "204"
+	case 205:
+		return "205"
+	case 206:
+		return "206"
+
+	case 300:
+		return "300"
+	case 301:
+		return "301"
+	case 302:
+		return "302"
+	case 304:
+		return "304"
+	case 305:
+		return "305"
+	case 307:
+		return "307"
+
+	case 400:
+		return "400"
+	case 401:
+		return "401"
+	case 402:
+		return "402"
+	case 403:
+		return "403"
+	case 404:
+		return "404"
+	case 405:
+		return "405"
+	case 406:
+		return "406"
+	case 407:
+		return "407"
+	case 408:
+		return "408"
+	case 409:
+		return "409"
+	case 410:
+		return "410"
+	case 411:
+		return "411"
+	case 412:
+		return "412"
+	case 413:
+		return "413"
+	case 414:
+		return "414"
+	case 415:
+		return "415"
+	case 416:
+		return "416"
+	case 417:
+		return "417"
+	case 418:
+		return "418"
+
+	case 500:
+		return "500"
+	case 501:
+		return "501"
+	case 502:
+		return "502"
+	case 503:
+		return "503"
+	case 504:
+		return "504"
+	case 505:
+		return "505"
+
+	case 428:
+		return "428"
+	case 429:
+		return "429"
+	case 431:
+		return "431"
+	case 511:
+		return "511"
+
+	default:
+		return strconv.Itoa(s)
+	}
+}

vendor/github.com/prometheus/client_golang/prometheus/registry.go

@@ -15,15 +15,23 @@ package prometheus
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
+	"io/ioutil"
 	"os"
+	"path/filepath"
+	"runtime"
 	"sort"
+	"strings"
 	"sync"
+	"unicode/utf8"
 
+	"github.com/cespare/xxhash/v2"
 	"github.com/golang/protobuf/proto"
+	"github.com/prometheus/common/expfmt"
 
 	dto "github.com/prometheus/client_model/go"
+
+	"github.com/prometheus/client_golang/prometheus/internal"
 )
 
 const (
@@ -35,13 +43,14 @@ const (
 // DefaultRegisterer and DefaultGatherer are the implementations of the
 // Registerer and Gatherer interface a number of convenience functions in this
 // package act on. Initially, both variables point to the same Registry, which
-// has a process collector (see NewProcessCollector) and a Go collector (see
-// NewGoCollector) already registered. This approach to keep default instances
-// as global state mirrors the approach of other packages in the Go standard
-// library. Note that there are caveats. Change the variables with caution and
-// only if you understand the consequences. Users who want to avoid global state
-// altogether should not use the convenience function and act on custom
-// instances instead.
+// has a process collector (currently on Linux only, see NewProcessCollector)
+// and a Go collector (see NewGoCollector, in particular the note about
+// stop-the-world implication with Go versions older than 1.9) already
+// registered. This approach to keep default instances as global state mirrors
+// the approach of other packages in the Go standard library. Note that there
+// are caveats. Change the variables with caution and only if you understand the
+// consequences. Users who want to avoid global state altogether should not use
+// the convenience functions and act on custom instances instead.
 var (
 	defaultRegistry              = NewRegistry()
 	DefaultRegisterer Registerer = defaultRegistry
@@ -49,7 +58,7 @@ var (
 )
 
 func init() {
-	MustRegister(NewProcessCollector(os.Getpid(), ""))
+	MustRegister(NewProcessCollector(ProcessCollectorOpts{}))
 	MustRegister(NewGoCollector())
 }
 
@@ -65,7 +74,8 @@ func NewRegistry() *Registry {
 
 // NewPedanticRegistry returns a registry that checks during collection if each
 // collected Metric is consistent with its reported Desc, and if the Desc has
-// actually been registered with the registry.
+// actually been registered with the registry. Unchecked Collectors (those whose
+// Describe method does not yield any descriptors) are excluded from the check.
 //
 // Usually, a Registry will be happy as long as the union of all collected
 // Metrics is consistent and valid even if some metrics are not consistent with
@@ -80,7 +90,7 @@ func NewPedanticRegistry() *Registry {
 
 // Registerer is the interface for the part of a registry in charge of
 // registering and unregistering. Users of custom registries should use
-// Registerer as type for registration purposes (rather then the Registry type
+// Registerer as type for registration purposes (rather than the Registry type
 // directly). In that way, they are free to use custom Registerer implementation
 // (e.g. for testing purposes).
 type Registerer interface {
@@ -95,8 +105,13 @@ type Registerer interface {
 	// returned error is an instance of AlreadyRegisteredError, which
 	// contains the previously registered Collector.
 	//
-	// It is in general not safe to register the same Collector multiple
-	// times concurrently.
+	// A Collector whose Describe method does not yield any Desc is treated
+	// as unchecked. Registration will always succeed. No check for
+	// re-registering (see previous paragraph) is performed. Thus, the
+	// caller is responsible for not double-registering the same unchecked
+	// Collector, and for providing a Collector that will not cause
+	// inconsistent metrics on collection. (This would lead to scrape
+	// errors.)
 	Register(Collector) error
 	// MustRegister works like Register but registers any number of
 	// Collectors and panics upon the first registration that causes an
@@ -105,7 +120,9 @@ type Registerer interface {
 	// Unregister unregisters the Collector that equals the Collector passed
 	// in as an argument.  (Two Collectors are considered equal if their
 	// Describe method yields the same set of descriptors.) The function
-	// returns whether a Collector was unregistered.
+	// returns whether a Collector was unregistered. Note that an unchecked
+	// Collector cannot be unregistered (as its Describe method does not
+	// yield any descriptor).
 	//
 	// Note that even after unregistering, it will not be possible to
 	// register a new Collector that is inconsistent with the unregistered
@@ -123,15 +140,23 @@ type Registerer interface {
 type Gatherer interface {
 	// Gather calls the Collect method of the registered Collectors and then
 	// gathers the collected metrics into a lexicographically sorted slice
-	// of MetricFamily protobufs. Even if an error occurs, Gather attempts
-	// to gather as many metrics as possible. Hence, if a non-nil error is
-	// returned, the returned MetricFamily slice could be nil (in case of a
-	// fatal error that prevented any meaningful metric collection) or
-	// contain a number of MetricFamily protobufs, some of which might be
-	// incomplete, and some might be missing altogether. The returned error
-	// (which might be a MultiError) explains the details. In scenarios
-	// where complete collection is critical, the returned MetricFamily
-	// protobufs should be disregarded if the returned error is non-nil.
+	// of uniquely named MetricFamily protobufs. Gather ensures that the
+	// returned slice is valid and self-consistent so that it can be used
+	// for valid exposition. As an exception to the strict consistency
+	// requirements described for metric.Desc, Gather will tolerate
+	// different sets of label names for metrics of the same metric family.
+	//
+	// Even if an error occurs, Gather attempts to gather as many metrics as
+	// possible. Hence, if a non-nil error is returned, the returned
+	// MetricFamily slice could be nil (in case of a fatal error that
+	// prevented any meaningful metric collection) or contain a number of
+	// MetricFamily protobufs, some of which might be incomplete, and some
+	// might be missing altogether. The returned error (which might be a
+	// MultiError) explains the details. Note that this is mostly useful for
+	// debugging purposes. If the gathered protobufs are to be used for
+	// exposition in actual monitoring, it is almost always better to not
+	// expose an incomplete result and instead disregard the returned
+	// MetricFamily protobufs in case the returned error is non-nil.
 	Gather() ([]*dto.MetricFamily, error)
 }
 
@@ -152,38 +177,6 @@ func MustRegister(cs ...Collector) {
 	DefaultRegisterer.MustRegister(cs...)
 }
 
-// RegisterOrGet registers the provided Collector with the DefaultRegisterer and
-// returns the Collector, unless an equal Collector was registered before, in
-// which case that Collector is returned.
-//
-// Deprecated: RegisterOrGet is merely a convenience function for the
-// implementation as described in the documentation for
-// AlreadyRegisteredError. As the use case is relatively rare, this function
-// will be removed in a future version of this package to clean up the
-// namespace.
-func RegisterOrGet(c Collector) (Collector, error) {
-	if err := Register(c); err != nil {
-		if are, ok := err.(AlreadyRegisteredError); ok {
-			return are.ExistingCollector, nil
-		}
-		return nil, err
-	}
-	return c, nil
-}
-
-// MustRegisterOrGet behaves like RegisterOrGet but panics instead of returning
-// an error.
-//
-// Deprecated: This is deprecated for the same reason RegisterOrGet is. See
-// there for details.
-func MustRegisterOrGet(c Collector) Collector {
-	c, err := RegisterOrGet(c)
-	if err != nil {
-		panic(err)
-	}
-	return c
-}
-
 // Unregister removes the registration of the provided Collector from the
 // DefaultRegisterer.
 //
@@ -201,25 +194,6 @@ func (gf GathererFunc) Gather() ([]*dto.MetricFamily, error) {
 	return gf()
 }
 
-// SetMetricFamilyInjectionHook replaces the DefaultGatherer with one that
-// gathers from the previous DefaultGatherers but then merges the MetricFamily
-// protobufs returned from the provided hook function with the MetricFamily
-// protobufs returned from the original DefaultGatherer.
-//
-// Deprecated: This function manipulates the DefaultGatherer variable. Consider
-// the implications, i.e. don't do this concurrently with any uses of the
-// DefaultGatherer. In the rare cases where you need to inject MetricFamily
-// protobufs directly, it is recommended to use a custom Registry and combine it
-// with a custom Gatherer using the Gatherers type (see
-// there). SetMetricFamilyInjectionHook only exists for compatibility reasons
-// with previous versions of this package.
-func SetMetricFamilyInjectionHook(hook func() []*dto.MetricFamily) {
-	DefaultGatherer = Gatherers{
-		DefaultGatherer,
-		GathererFunc(func() ([]*dto.MetricFamily, error) { return hook(), nil }),
-	}
-}
-
 // AlreadyRegisteredError is returned by the Register method if the Collector to
 // be registered has already been registered before, or a different Collector
 // that collects the same metrics has been registered before. Registration fails
@@ -252,6 +226,13 @@ func (errs MultiError) Error() string {
 	return buf.String()
 }
 
+// Append appends the provided error if it is not nil.
+func (errs *MultiError) Append(err error) {
+	if err != nil {
+		*errs = append(*errs, err)
+	}
+}
+
 // MaybeUnwrap returns nil if len(errs) is 0. It returns the first and only
 // contained error as error if len(errs is 1). In all other cases, it returns
 // the MultiError directly. This is helpful for returning a MultiError in a way
@@ -276,6 +257,7 @@ type Registry struct {
 	collectorsByID        map[uint64]Collector // ID is a hash of the descIDs.
 	descIDs               map[uint64]struct{}
 	dimHashesByName       map[string]uint64
+	uncheckedCollectors   []Collector
 	pedanticChecksEnabled bool
 }
 
@@ -285,7 +267,7 @@ func (r *Registry) Register(c Collector) error {
 		descChan           = make(chan *Desc, capDescChan)
 		newDescIDs         = map[uint64]struct{}{}
 		newDimHashesByName = map[string]uint64{}
-		collectorID        uint64 // Just a sum of all desc IDs.
+		collectorID        uint64 // All desc IDs XOR'd together.
 		duplicateDescErr   error
 	)
 	go func() {
@@ -293,8 +275,13 @@ func (r *Registry) Register(c Collector) error {
 		close(descChan)
 	}()
 	r.mtx.Lock()
-	defer r.mtx.Unlock()
-	// Coduct various tests...
+	defer func() {
+		// Drain channel in case of premature return to not leak a goroutine.
+		for range descChan {
+		}
+		r.mtx.Unlock()
+	}()
+	// Conduct various tests...
 	for desc := range descChan {
 
 		// Is the descriptor valid at all?
@@ -307,12 +294,12 @@ func (r *Registry) Register(c Collector) error {
 		if _, exists := r.descIDs[desc.id]; exists {
 			duplicateDescErr = fmt.Errorf("descriptor %s already exists with the same fully-qualified name and const label values", desc)
 		}
-		// If it is not a duplicate desc in this collector, add it to
+		// If it is not a duplicate desc in this collector, XOR it to
 		// the collectorID.  (We allow duplicate descs within the same
 		// collector, but their existence must be a no-op.)
 		if _, exists := newDescIDs[desc.id]; !exists {
 			newDescIDs[desc.id] = struct{}{}
-			collectorID += desc.id
+			collectorID ^= desc.id
 		}
 
 		// Are all the label names and the help string consistent with
@@ -333,14 +320,23 @@ func (r *Registry) Register(c Collector) error {
 			}
 		}
 	}
-	// Did anything happen at all?
+	// A Collector yielding no Desc at all is considered unchecked.
 	if len(newDescIDs) == 0 {
-		return errors.New("collector has no descriptors")
+		r.uncheckedCollectors = append(r.uncheckedCollectors, c)
+		return nil
 	}
 	if existing, exists := r.collectorsByID[collectorID]; exists {
-		return AlreadyRegisteredError{
-			ExistingCollector: existing,
-			NewCollector:      c,
+		switch e := existing.(type) {
+		case *wrappingCollector:
+			return AlreadyRegisteredError{
+				ExistingCollector: e.unwrapRecursively(),
+				NewCollector:      c,
+			}
+		default:
+			return AlreadyRegisteredError{
+				ExistingCollector: e,
+				NewCollector:      c,
+			}
 		}
 	}
 	// If the collectorID is new, but at least one of the descs existed
@@ -365,7 +361,7 @@ func (r *Registry) Unregister(c Collector) bool {
 	var (
 		descChan    = make(chan *Desc, capDescChan)
 		descIDs     = map[uint64]struct{}{}
-		collectorID uint64 // Just a sum of the desc IDs.
+		collectorID uint64 // All desc IDs XOR'd together.
 	)
 	go func() {
 		c.Describe(descChan)
@@ -373,7 +369,7 @@ func (r *Registry) Unregister(c Collector) bool {
 	}()
 	for desc := range descChan {
 		if _, exists := descIDs[desc.id]; !exists {
-			collectorID += desc.id
+			collectorID ^= desc.id
 			descIDs[desc.id] = struct{}{}
 		}
 	}
@@ -409,31 +405,25 @@ func (r *Registry) MustRegister(cs ...Collector) {
 // Gather implements Gatherer.
 func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
 	var (
-		metricChan        = make(chan Metric, capMetricChan)
-		metricHashes      = map[uint64]struct{}{}
-		dimHashes         = map[string]uint64{}
-		wg                sync.WaitGroup
-		errs              MultiError          // The collected errors to return in the end.
-		registeredDescIDs map[uint64]struct{} // Only used for pedantic checks
+		checkedMetricChan   = make(chan Metric, capMetricChan)
+		uncheckedMetricChan = make(chan Metric, capMetricChan)
+		metricHashes        = map[uint64]struct{}{}
+		wg                  sync.WaitGroup
+		errs                MultiError          // The collected errors to return in the end.
+		registeredDescIDs   map[uint64]struct{} // Only used for pedantic checks
 	)
 
 	r.mtx.RLock()
+	goroutineBudget := len(r.collectorsByID) + len(r.uncheckedCollectors)
 	metricFamiliesByName := make(map[string]*dto.MetricFamily, len(r.dimHashesByName))
-
-	// Scatter.
-	// (Collectors could be complex and slow, so we call them all at once.)
-	wg.Add(len(r.collectorsByID))
-	go func() {
-		wg.Wait()
-		close(metricChan)
-	}()
+	checkedCollectors := make(chan Collector, len(r.collectorsByID))
+	uncheckedCollectors := make(chan Collector, len(r.uncheckedCollectors))
 	for _, collector := range r.collectorsByID {
-		go func(collector Collector) {
-			defer wg.Done()
-			collector.Collect(metricChan)
-		}(collector)
+		checkedCollectors <- collector
+	}
+	for _, collector := range r.uncheckedCollectors {
+		uncheckedCollectors <- collector
 	}
-
 	// In case pedantic checks are enabled, we have to copy the map before
 	// giving up the RLock.
 	if r.pedanticChecksEnabled {
@@ -442,133 +432,264 @@ func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
 			registeredDescIDs[id] = struct{}{}
 		}
 	}
-
 	r.mtx.RUnlock()
 
-	// Drain metricChan in case of premature return.
+	wg.Add(goroutineBudget)
+
+	collectWorker := func() {
+		for {
+			select {
+			case collector := <-checkedCollectors:
+				collector.Collect(checkedMetricChan)
+			case collector := <-uncheckedCollectors:
+				collector.Collect(uncheckedMetricChan)
+			default:
+				return
+			}
+			wg.Done()
+		}
+	}
+
+	// Start the first worker now to make sure at least one is running.
+	go collectWorker()
+	goroutineBudget--
+
+	// Close checkedMetricChan and uncheckedMetricChan once all collectors
+	// are collected.
+	go func() {
+		wg.Wait()
+		close(checkedMetricChan)
+		close(uncheckedMetricChan)
+	}()
+
+	// Drain checkedMetricChan and uncheckedMetricChan in case of premature return.
 	defer func() {
-		for _ = range metricChan {
+		if checkedMetricChan != nil {
+			for range checkedMetricChan {
+			}
+		}
+		if uncheckedMetricChan != nil {
+			for range uncheckedMetricChan {
+			}
 		}
 	}()
 
-	// Gather.
-	for metric := range metricChan {
-		// This could be done concurrently, too, but it required locking
-		// of metricFamiliesByName (and of metricHashes if checks are
-		// enabled). Most likely not worth it.
-		desc := metric.Desc()
-		dtoMetric := &dto.Metric{}
-		if err := metric.Write(dtoMetric); err != nil {
-			errs = append(errs, fmt.Errorf(
-				"error collecting metric %v: %s", desc, err,
+	// Copy the channel references so we can nil them out later to remove
+	// them from the select statements below.
+	cmc := checkedMetricChan
+	umc := uncheckedMetricChan
+
+	for {
+		select {
+		case metric, ok := <-cmc:
+			if !ok {
+				cmc = nil
+				break
+			}
+			errs.Append(processMetric(
+				metric, metricFamiliesByName,
+				metricHashes,
+				registeredDescIDs,
 			))
-			continue
+		case metric, ok := <-umc:
+			if !ok {
+				umc = nil
+				break
+			}
+			errs.Append(processMetric(
+				metric, metricFamiliesByName,
+				metricHashes,
+				nil,
+			))
+		default:
+			if goroutineBudget <= 0 || len(checkedCollectors)+len(uncheckedCollectors) == 0 {
+				// All collectors are already being worked on or
+				// we have already as many goroutines started as
+				// there are collectors. Do the same as above,
+				// just without the default.
+				select {
+				case metric, ok := <-cmc:
+					if !ok {
+						cmc = nil
+						break
+					}
+					errs.Append(processMetric(
+						metric, metricFamiliesByName,
+						metricHashes,
+						registeredDescIDs,
+					))
+				case metric, ok := <-umc:
+					if !ok {
+						umc = nil
+						break
+					}
+					errs.Append(processMetric(
+						metric, metricFamiliesByName,
+						metricHashes,
+						nil,
+					))
+				}
+				break
+			}
+			// Start more workers.
+			go collectWorker()
+			goroutineBudget--
+			runtime.Gosched()
 		}
-		metricFamily, ok := metricFamiliesByName[desc.fqName]
-		if ok {
-			if metricFamily.GetHelp() != desc.help {
-				errs = append(errs, fmt.Errorf(
-					"collected metric %s %s has help %q but should have %q",
-					desc.fqName, dtoMetric, desc.help, metricFamily.GetHelp(),
-				))
-				continue
-			}
-			// TODO(beorn7): Simplify switch once Desc has type.
-			switch metricFamily.GetType() {
-			case dto.MetricType_COUNTER:
-				if dtoMetric.Counter == nil {
-					errs = append(errs, fmt.Errorf(
-						"collected metric %s %s should be a Counter",
-						desc.fqName, dtoMetric,
-					))
-					continue
-				}
-			case dto.MetricType_GAUGE:
-				if dtoMetric.Gauge == nil {
-					errs = append(errs, fmt.Errorf(
-						"collected metric %s %s should be a Gauge",
-						desc.fqName, dtoMetric,
-					))
-					continue
-				}
-			case dto.MetricType_SUMMARY:
-				if dtoMetric.Summary == nil {
-					errs = append(errs, fmt.Errorf(
-						"collected metric %s %s should be a Summary",
-						desc.fqName, dtoMetric,
-					))
-					continue
-				}
-			case dto.MetricType_UNTYPED:
-				if dtoMetric.Untyped == nil {
-					errs = append(errs, fmt.Errorf(
-						"collected metric %s %s should be Untyped",
-						desc.fqName, dtoMetric,
-					))
-					continue
-				}
-			case dto.MetricType_HISTOGRAM:
-				if dtoMetric.Histogram == nil {
-					errs = append(errs, fmt.Errorf(
-						"collected metric %s %s should be a Histogram",
-						desc.fqName, dtoMetric,
-					))
-					continue
-				}
-			default:
-				panic("encountered MetricFamily with invalid type")
-			}
-		} else {
-			metricFamily = &dto.MetricFamily{}
-			metricFamily.Name = proto.String(desc.fqName)
-			metricFamily.Help = proto.String(desc.help)
-			// TODO(beorn7): Simplify switch once Desc has type.
-			switch {
-			case dtoMetric.Gauge != nil:
-				metricFamily.Type = dto.MetricType_GAUGE.Enum()
-			case dtoMetric.Counter != nil:
-				metricFamily.Type = dto.MetricType_COUNTER.Enum()
-			case dtoMetric.Summary != nil:
-				metricFamily.Type = dto.MetricType_SUMMARY.Enum()
-			case dtoMetric.Untyped != nil:
-				metricFamily.Type = dto.MetricType_UNTYPED.Enum()
-			case dtoMetric.Histogram != nil:
-				metricFamily.Type = dto.MetricType_HISTOGRAM.Enum()
-			default:
-				errs = append(errs, fmt.Errorf(
-					"empty metric collected: %s", dtoMetric,
-				))
-				continue
-			}
-			metricFamiliesByName[desc.fqName] = metricFamily
+		// Once both checkedMetricChan and uncheckdMetricChan are closed
+		// and drained, the contraption above will nil out cmc and umc,
+		// and then we can leave the collect loop here.
+		if cmc == nil && umc == nil {
+			break
 		}
-		if err := checkMetricConsistency(metricFamily, dtoMetric, metricHashes, dimHashes); err != nil {
-			errs = append(errs, err)
-			continue
-		}
-		if r.pedanticChecksEnabled {
-			// Is the desc registered at all?
-			if _, exist := registeredDescIDs[desc.id]; !exist {
-				errs = append(errs, fmt.Errorf(
-					"collected metric %s %s with unregistered descriptor %s",
-					metricFamily.GetName(), dtoMetric, desc,
-				))
-				continue
-			}
-			if err := checkDescConsistency(metricFamily, dtoMetric, desc); err != nil {
-				errs = append(errs, err)
-				continue
-			}
-		}
-		metricFamily.Metric = append(metricFamily.Metric, dtoMetric)
 	}
-	return normalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
+	return internal.NormalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
+}
+
+// WriteToTextfile calls Gather on the provided Gatherer, encodes the result in the
+// Prometheus text format, and writes it to a temporary file. Upon success, the
+// temporary file is renamed to the provided filename.
+//
+// This is intended for use with the textfile collector of the node exporter.
+// Note that the node exporter expects the filename to be suffixed with ".prom".
+func WriteToTextfile(filename string, g Gatherer) error {
+	tmp, err := ioutil.TempFile(filepath.Dir(filename), filepath.Base(filename))
+	if err != nil {
+		return err
+	}
+	defer os.Remove(tmp.Name())
+
+	mfs, err := g.Gather()
+	if err != nil {
+		return err
+	}
+	for _, mf := range mfs {
+		if _, err := expfmt.MetricFamilyToText(tmp, mf); err != nil {
+			return err
+		}
+	}
+	if err := tmp.Close(); err != nil {
+		return err
+	}
+
+	if err := os.Chmod(tmp.Name(), 0644); err != nil {
+		return err
+	}
+	return os.Rename(tmp.Name(), filename)
+}
+
+// processMetric is an internal helper method only used by the Gather method.
+func processMetric(
+	metric Metric,
+	metricFamiliesByName map[string]*dto.MetricFamily,
+	metricHashes map[uint64]struct{},
+	registeredDescIDs map[uint64]struct{},
+) error {
+	desc := metric.Desc()
+	// Wrapped metrics collected by an unchecked Collector can have an
+	// invalid Desc.
+	if desc.err != nil {
+		return desc.err
+	}
+	dtoMetric := &dto.Metric{}
+	if err := metric.Write(dtoMetric); err != nil {
+		return fmt.Errorf("error collecting metric %v: %s", desc, err)
+	}
+	metricFamily, ok := metricFamiliesByName[desc.fqName]
+	if ok { // Existing name.
+		if metricFamily.GetHelp() != desc.help {
+			return fmt.Errorf(
+				"collected metric %s %s has help %q but should have %q",
+				desc.fqName, dtoMetric, desc.help, metricFamily.GetHelp(),
+			)
+		}
+		// TODO(beorn7): Simplify switch once Desc has type.
+		switch metricFamily.GetType() {
+		case dto.MetricType_COUNTER:
+			if dtoMetric.Counter == nil {
+				return fmt.Errorf(
+					"collected metric %s %s should be a Counter",
+					desc.fqName, dtoMetric,
+				)
+			}
+		case dto.MetricType_GAUGE:
+			if dtoMetric.Gauge == nil {
+				return fmt.Errorf(
+					"collected metric %s %s should be a Gauge",
+					desc.fqName, dtoMetric,
+				)
+			}
+		case dto.MetricType_SUMMARY:
+			if dtoMetric.Summary == nil {
+				return fmt.Errorf(
+					"collected metric %s %s should be a Summary",
+					desc.fqName, dtoMetric,
+				)
+			}
+		case dto.MetricType_UNTYPED:
+			if dtoMetric.Untyped == nil {
+				return fmt.Errorf(
+					"collected metric %s %s should be Untyped",
+					desc.fqName, dtoMetric,
+				)
+			}
+		case dto.MetricType_HISTOGRAM:
+			if dtoMetric.Histogram == nil {
+				return fmt.Errorf(
+					"collected metric %s %s should be a Histogram",
+					desc.fqName, dtoMetric,
+				)
+			}
+		default:
+			panic("encountered MetricFamily with invalid type")
+		}
+	} else { // New name.
+		metricFamily = &dto.MetricFamily{}
+		metricFamily.Name = proto.String(desc.fqName)
+		metricFamily.Help = proto.String(desc.help)
+		// TODO(beorn7): Simplify switch once Desc has type.
+		switch {
+		case dtoMetric.Gauge != nil:
+			metricFamily.Type = dto.MetricType_GAUGE.Enum()
+		case dtoMetric.Counter != nil:
+			metricFamily.Type = dto.MetricType_COUNTER.Enum()
+		case dtoMetric.Summary != nil:
+			metricFamily.Type = dto.MetricType_SUMMARY.Enum()
+		case dtoMetric.Untyped != nil:
+			metricFamily.Type = dto.MetricType_UNTYPED.Enum()
+		case dtoMetric.Histogram != nil:
+			metricFamily.Type = dto.MetricType_HISTOGRAM.Enum()
+		default:
+			return fmt.Errorf("empty metric collected: %s", dtoMetric)
+		}
+		if err := checkSuffixCollisions(metricFamily, metricFamiliesByName); err != nil {
+			return err
+		}
+		metricFamiliesByName[desc.fqName] = metricFamily
+	}
+	if err := checkMetricConsistency(metricFamily, dtoMetric, metricHashes); err != nil {
+		return err
+	}
+	if registeredDescIDs != nil {
+		// Is the desc registered at all?
+		if _, exist := registeredDescIDs[desc.id]; !exist {
+			return fmt.Errorf(
+				"collected metric %s %s with unregistered descriptor %s",
+				metricFamily.GetName(), dtoMetric, desc,
+			)
+		}
+		if err := checkDescConsistency(metricFamily, dtoMetric, desc); err != nil {
+			return err
+		}
+	}
+	metricFamily.Metric = append(metricFamily.Metric, dtoMetric)
+	return nil
 }
 
 // Gatherers is a slice of Gatherer instances that implements the Gatherer
 // interface itself. Its Gather method calls Gather on all Gatherers in the
 // slice in order and returns the merged results. Errors returned from the
-// Gather calles are all returned in a flattened MultiError. Duplicate and
+// Gather calls are all returned in a flattened MultiError. Duplicate and
 // inconsistent Metrics are skipped (first occurrence in slice order wins) and
 // reported in the returned error.
 //
@@ -588,7 +709,6 @@ func (gs Gatherers) Gather() ([]*dto.MetricFamily, error) {
 	var (
 		metricFamiliesByName = map[string]*dto.MetricFamily{}
 		metricHashes         = map[uint64]struct{}{}
-		dimHashes            = map[string]uint64{}
 		errs                 MultiError // The collected errors to return in the end.
 	)
 
@@ -625,10 +745,14 @@ func (gs Gatherers) Gather() ([]*dto.MetricFamily, error) {
 				existingMF.Name = mf.Name
 				existingMF.Help = mf.Help
 				existingMF.Type = mf.Type
+				if err := checkSuffixCollisions(existingMF, metricFamiliesByName); err != nil {
+					errs = append(errs, err)
+					continue
+				}
 				metricFamiliesByName[mf.GetName()] = existingMF
 			}
 			for _, m := range mf.Metric {
-				if err := checkMetricConsistency(existingMF, m, metricHashes, dimHashes); err != nil {
+				if err := checkMetricConsistency(existingMF, m, metricHashes); err != nil {
 					errs = append(errs, err)
 					continue
 				}
@@ -636,88 +760,80 @@ func (gs Gatherers) Gather() ([]*dto.MetricFamily, error) {
 			}
 		}
 	}
-	return normalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
+	return internal.NormalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
 }
 
-// metricSorter is a sortable slice of *dto.Metric.
-type metricSorter []*dto.Metric
-
-func (s metricSorter) Len() int {
-	return len(s)
-}
-
-func (s metricSorter) Swap(i, j int) {
-	s[i], s[j] = s[j], s[i]
-}
-
-func (s metricSorter) Less(i, j int) bool {
-	if len(s[i].Label) != len(s[j].Label) {
-		// This should not happen. The metrics are
-		// inconsistent. However, we have to deal with the fact, as
-		// people might use custom collectors or metric family injection
-		// to create inconsistent metrics. So let's simply compare the
-		// number of labels in this case. That will still yield
-		// reproducible sorting.
-		return len(s[i].Label) < len(s[j].Label)
+// checkSuffixCollisions checks for collisions with the “magic” suffixes the
+// Prometheus text format and the internal metric representation of the
+// Prometheus server add while flattening Summaries and Histograms.
+func checkSuffixCollisions(mf *dto.MetricFamily, mfs map[string]*dto.MetricFamily) error {
+	var (
+		newName              = mf.GetName()
+		newType              = mf.GetType()
+		newNameWithoutSuffix = ""
+	)
+	switch {
+	case strings.HasSuffix(newName, "_count"):
+		newNameWithoutSuffix = newName[:len(newName)-6]
+	case strings.HasSuffix(newName, "_sum"):
+		newNameWithoutSuffix = newName[:len(newName)-4]
+	case strings.HasSuffix(newName, "_bucket"):
+		newNameWithoutSuffix = newName[:len(newName)-7]
 	}
-	for n, lp := range s[i].Label {
-		vi := lp.GetValue()
-		vj := s[j].Label[n].GetValue()
-		if vi != vj {
-			return vi < vj
+	if newNameWithoutSuffix != "" {
+		if existingMF, ok := mfs[newNameWithoutSuffix]; ok {
+			switch existingMF.GetType() {
+			case dto.MetricType_SUMMARY:
+				if !strings.HasSuffix(newName, "_bucket") {
+					return fmt.Errorf(
+						"collected metric named %q collides with previously collected summary named %q",
+						newName, newNameWithoutSuffix,
+					)
+				}
+			case dto.MetricType_HISTOGRAM:
+				return fmt.Errorf(
+					"collected metric named %q collides with previously collected histogram named %q",
+					newName, newNameWithoutSuffix,
+				)
+			}
 		}
 	}
-
-	// We should never arrive here. Multiple metrics with the same
-	// label set in the same scrape will lead to undefined ingestion
-	// behavior. However, as above, we have to provide stable sorting
-	// here, even for inconsistent metrics. So sort equal metrics
-	// by their timestamp, with missing timestamps (implying "now")
-	// coming last.
-	if s[i].TimestampMs == nil {
-		return false
-	}
-	if s[j].TimestampMs == nil {
-		return true
-	}
-	return s[i].GetTimestampMs() < s[j].GetTimestampMs()
-}
-
-// normalizeMetricFamilies returns a MetricFamily slice whith empty
-// MetricFamilies pruned and the remaining MetricFamilies sorted by name within
-// the slice, with the contained Metrics sorted within each MetricFamily.
-func normalizeMetricFamilies(metricFamiliesByName map[string]*dto.MetricFamily) []*dto.MetricFamily {
-	for _, mf := range metricFamiliesByName {
-		sort.Sort(metricSorter(mf.Metric))
-	}
-	names := make([]string, 0, len(metricFamiliesByName))
-	for name, mf := range metricFamiliesByName {
-		if len(mf.Metric) > 0 {
-			names = append(names, name)
+	if newType == dto.MetricType_SUMMARY || newType == dto.MetricType_HISTOGRAM {
+		if _, ok := mfs[newName+"_count"]; ok {
+			return fmt.Errorf(
+				"collected histogram or summary named %q collides with previously collected metric named %q",
+				newName, newName+"_count",
+			)
+		}
+		if _, ok := mfs[newName+"_sum"]; ok {
+			return fmt.Errorf(
+				"collected histogram or summary named %q collides with previously collected metric named %q",
+				newName, newName+"_sum",
+			)
 		}
 	}
-	sort.Strings(names)
-	result := make([]*dto.MetricFamily, 0, len(names))
-	for _, name := range names {
-		result = append(result, metricFamiliesByName[name])
+	if newType == dto.MetricType_HISTOGRAM {
+		if _, ok := mfs[newName+"_bucket"]; ok {
+			return fmt.Errorf(
+				"collected histogram named %q collides with previously collected metric named %q",
+				newName, newName+"_bucket",
+			)
+		}
 	}
-	return result
+	return nil
 }
 
 // checkMetricConsistency checks if the provided Metric is consistent with the
-// provided MetricFamily. It also hashed the Metric labels and the MetricFamily
-// name. If the resulting hash is alread in the provided metricHashes, an error
-// is returned. If not, it is added to metricHashes. The provided dimHashes maps
-// MetricFamily names to their dimHash (hashed sorted label names). If dimHashes
-// doesn't yet contain a hash for the provided MetricFamily, it is
-// added. Otherwise, an error is returned if the existing dimHashes in not equal
-// the calculated dimHash.
+// provided MetricFamily. It also hashes the Metric labels and the MetricFamily
+// name. If the resulting hash is already in the provided metricHashes, an error
+// is returned. If not, it is added to metricHashes.
 func checkMetricConsistency(
 	metricFamily *dto.MetricFamily,
 	dtoMetric *dto.Metric,
 	metricHashes map[uint64]struct{},
-	dimHashes map[string]uint64,
 ) error {
+	name := metricFamily.GetName()
+
 	// Type consistency with metric family.
 	if metricFamily.GetType() == dto.MetricType_GAUGE && dtoMetric.Gauge == nil ||
 		metricFamily.GetType() == dto.MetricType_COUNTER && dtoMetric.Counter == nil ||
@@ -725,42 +841,67 @@ func checkMetricConsistency(
 		metricFamily.GetType() == dto.MetricType_HISTOGRAM && dtoMetric.Histogram == nil ||
 		metricFamily.GetType() == dto.MetricType_UNTYPED && dtoMetric.Untyped == nil {
 		return fmt.Errorf(
-			"collected metric %s %s is not a %s",
-			metricFamily.GetName(), dtoMetric, metricFamily.GetType(),
+			"collected metric %q { %s} is not a %s",
+			name, dtoMetric, metricFamily.GetType(),
 		)
 	}
 
-	// Is the metric unique (i.e. no other metric with the same name and the same label values)?
-	h := hashNew()
-	h = hashAdd(h, metricFamily.GetName())
-	h = hashAddByte(h, separatorByte)
-	dh := hashNew()
-	// Make sure label pairs are sorted. We depend on it for the consistency
-	// check.
-	sort.Sort(LabelPairSorter(dtoMetric.Label))
-	for _, lp := range dtoMetric.Label {
-		h = hashAdd(h, lp.GetValue())
-		h = hashAddByte(h, separatorByte)
-		dh = hashAdd(dh, lp.GetName())
-		dh = hashAddByte(dh, separatorByte)
-	}
-	if _, exists := metricHashes[h]; exists {
-		return fmt.Errorf(
-			"collected metric %s %s was collected before with the same name and label values",
-			metricFamily.GetName(), dtoMetric,
-		)
-	}
-	if dimHash, ok := dimHashes[metricFamily.GetName()]; ok {
-		if dimHash != dh {
+	previousLabelName := ""
+	for _, labelPair := range dtoMetric.GetLabel() {
+		labelName := labelPair.GetName()
+		if labelName == previousLabelName {
 			return fmt.Errorf(
-				"collected metric %s %s has label dimensions inconsistent with previously collected metrics in the same metric family",
-				metricFamily.GetName(), dtoMetric,
+				"collected metric %q { %s} has two or more labels with the same name: %s",
+				name, dtoMetric, labelName,
 			)
 		}
-	} else {
-		dimHashes[metricFamily.GetName()] = dh
+		if !checkLabelName(labelName) {
+			return fmt.Errorf(
+				"collected metric %q { %s} has a label with an invalid name: %s",
+				name, dtoMetric, labelName,
+			)
+		}
+		if dtoMetric.Summary != nil && labelName == quantileLabel {
+			return fmt.Errorf(
+				"collected metric %q { %s} must not have an explicit %q label",
+				name, dtoMetric, quantileLabel,
+			)
+		}
+		if !utf8.ValidString(labelPair.GetValue()) {
+			return fmt.Errorf(
+				"collected metric %q { %s} has a label named %q whose value is not utf8: %#v",
+				name, dtoMetric, labelName, labelPair.GetValue())
+		}
+		previousLabelName = labelName
 	}
-	metricHashes[h] = struct{}{}
+
+	// Is the metric unique (i.e. no other metric with the same name and the same labels)?
+	h := xxhash.New()
+	h.WriteString(name)
+	h.Write(separatorByteSlice)
+	// Make sure label pairs are sorted. We depend on it for the consistency
+	// check.
+	if !sort.IsSorted(labelPairSorter(dtoMetric.Label)) {
+		// We cannot sort dtoMetric.Label in place as it is immutable by contract.
+		copiedLabels := make([]*dto.LabelPair, len(dtoMetric.Label))
+		copy(copiedLabels, dtoMetric.Label)
+		sort.Sort(labelPairSorter(copiedLabels))
+		dtoMetric.Label = copiedLabels
+	}
+	for _, lp := range dtoMetric.Label {
+		h.WriteString(lp.GetName())
+		h.Write(separatorByteSlice)
+		h.WriteString(lp.GetValue())
+		h.Write(separatorByteSlice)
+	}
+	hSum := h.Sum64()
+	if _, exists := metricHashes[hSum]; exists {
+		return fmt.Errorf(
+			"collected metric %q { %s} was collected before with the same name and label values",
+			name, dtoMetric,
+		)
+	}
+	metricHashes[hSum] = struct{}{}
 	return nil
 }
 
@@ -778,8 +919,8 @@ func checkDescConsistency(
 	}
 
 	// Is the desc consistent with the content of the metric?
-	lpsFromDesc := make([]*dto.LabelPair, 0, len(dtoMetric.Label))
-	lpsFromDesc = append(lpsFromDesc, desc.constLabelPairs...)
+	lpsFromDesc := make([]*dto.LabelPair, len(desc.constLabelPairs), len(dtoMetric.Label))
+	copy(lpsFromDesc, desc.constLabelPairs)
 	for _, l := range desc.variableLabels {
 		lpsFromDesc = append(lpsFromDesc, &dto.LabelPair{
 			Name: proto.String(l),
@@ -791,7 +932,7 @@ func checkDescConsistency(
 			metricFamily.GetName(), dtoMetric, desc,
 		)
 	}
-	sort.Sort(LabelPairSorter(lpsFromDesc))
+	sort.Sort(labelPairSorter(lpsFromDesc))
 	for i, lpFromDesc := range lpsFromDesc {
 		lpFromMetric := dtoMetric.Label[i]
 		if lpFromDesc.GetName() != lpFromMetric.GetName() ||

vendor/github.com/prometheus/client_golang/prometheus/summary.go

@@ -16,8 +16,10 @@ package prometheus
 import (
 	"fmt"
 	"math"
+	"runtime"
 	"sort"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/beorn7/perks/quantile"
@@ -36,7 +38,10 @@ const quantileLabel = "quantile"
 //
 // A typical use-case is the observation of request latencies. By default, a
 // Summary provides the median, the 90th and the 99th percentile of the latency
-// as rank estimations.
+// as rank estimations. However, the default behavior will change in the
+// upcoming v1.0.0 of the library. There will be no rank estimations at all by
+// default. For a sane transition, it is recommended to set the desired rank
+// estimations explicitly.
 //
 // Note that the rank estimations cannot be aggregated in a meaningful way with
 // the Prometheus query language (i.e. you cannot average or add them). If you
@@ -53,13 +58,8 @@ type Summary interface {
 	Observe(float64)
 }
 
-// DefObjectives are the default Summary quantile values.
-var (
-	DefObjectives = map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001}
-
-	errQuantileLabelNotAllowed = fmt.Errorf(
-		"%q is not allowed as label name in summaries", quantileLabel,
-	)
+var errQuantileLabelNotAllowed = fmt.Errorf(
+	"%q is not allowed as label name in summaries", quantileLabel,
 )
 
 // Default values for SummaryOpts.
@@ -75,8 +75,10 @@ const (
 )
 
 // SummaryOpts bundles the options for creating a Summary metric. It is
-// mandatory to set Name and Help to a non-empty string. All other fields are
-// optional and can safely be left at their zero value.
+// mandatory to set Name to a non-empty string. While all other fields are
+// optional and can safely be left at their zero value, it is recommended to set
+// a help string and to explicitly set the Objectives field to the desired value
+// as the default value will change in the upcoming v1.0.0 of the library.
 type SummaryOpts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Summary (created by joining these components with
@@ -87,35 +89,34 @@ type SummaryOpts struct {
 	Subsystem string
 	Name      string
 
-	// Help provides information about this Summary. Mandatory!
+	// Help provides information about this Summary.
 	//
 	// Metrics with the same fully-qualified name must have the same Help
 	// string.
 	Help string
 
-	// ConstLabels are used to attach fixed labels to this
-	// Summary. Summaries with the same fully-qualified name must have the
-	// same label names in their ConstLabels.
+	// ConstLabels are used to attach fixed labels to this metric. Metrics
+	// with the same fully-qualified name must have the same label names in
+	// their ConstLabels.
 	//
-	// Note that in most cases, labels have a value that varies during the
-	// lifetime of a process. Those labels are usually managed with a
-	// SummaryVec. ConstLabels serve only special purposes. One is for the
-	// special case where the value of a label does not change during the
-	// lifetime of a process, e.g. if the revision of the running binary is
-	// put into a label. Another, more advanced purpose is if more than one
-	// Collector needs to collect Summaries with the same fully-qualified
-	// name. In that case, those Summaries must differ in the values of
-	// their ConstLabels. See the Collector examples.
+	// Due to the way a Summary is represented in the Prometheus text format
+	// and how it is handled by the Prometheus server internally, “quantile”
+	// is an illegal label name. Construction of a Summary or SummaryVec
+	// will panic if this label name is used in ConstLabels.
 	//
-	// If the value of a label never changes (not even between binaries),
-	// that label most likely should not be a label at all (but part of the
-	// metric name).
+	// ConstLabels are only used rarely. In particular, do not use them to
+	// attach the same labels to all your metrics. Those use cases are
+	// better covered by target labels set by the scraping Prometheus
+	// server, or by one specific metric (e.g. a build_info or a
+	// machine_role metric). See also
+	// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels,-not-static-scraped-labels
 	ConstLabels Labels
 
 	// Objectives defines the quantile rank estimates with their respective
-	// absolute error. If Objectives[q] = e, then the value reported
-	// for q will be the φ-quantile value for some φ between q-e and q+e.
-	// The default value is DefObjectives.
+	// absolute error. If Objectives[q] = e, then the value reported for q
+	// will be the φ-quantile value for some φ between q-e and q+e.  The
+	// default value is an empty map, resulting in a summary without
+	// quantiles.
 	Objectives map[float64]float64
 
 	// MaxAge defines the duration for which an observation stays relevant
@@ -139,7 +140,7 @@ type SummaryOpts struct {
 	BufCap uint32
 }
 
-// Great fuck-up with the sliding-window decay algorithm... The Merge method of
+// Problem with the sliding-window decay algorithm... The Merge method of
 // perk/quantile is actually not working as advertised - and it might be
 // unfixable, as the underlying algorithm is apparently not capable of merging
 // summaries in the first place. To avoid using Merge, we are currently adding
@@ -169,7 +170,7 @@ func NewSummary(opts SummaryOpts) Summary {
 
 func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 	if len(desc.variableLabels) != len(labelValues) {
-		panic(errInconsistentCardinality)
+		panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, labelValues))
 	}
 
 	for _, n := range desc.variableLabels {
@@ -183,8 +184,8 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 		}
 	}
 
-	if len(opts.Objectives) == 0 {
-		opts.Objectives = DefObjectives
+	if opts.Objectives == nil {
+		opts.Objectives = map[float64]float64{}
 	}
 
 	if opts.MaxAge < 0 {
@@ -202,6 +203,17 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 		opts.BufCap = DefBufCap
 	}
 
+	if len(opts.Objectives) == 0 {
+		// Use the lock-free implementation of a Summary without objectives.
+		s := &noObjectivesSummary{
+			desc:       desc,
+			labelPairs: makeLabelPairs(desc, labelValues),
+			counts:     [2]*summaryCounts{{}, {}},
+		}
+		s.init(s) // Init self-collection.
+		return s
+	}
+
 	s := &summary{
 		desc: desc,
 
@@ -370,6 +382,116 @@ func (s *summary) swapBufs(now time.Time) {
 	}
 }
 
+type summaryCounts struct {
+	// sumBits contains the bits of the float64 representing the sum of all
+	// observations. sumBits and count have to go first in the struct to
+	// guarantee alignment for atomic operations.
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	sumBits uint64
+	count   uint64
+}
+
+type noObjectivesSummary struct {
+	// countAndHotIdx enables lock-free writes with use of atomic updates.
+	// The most significant bit is the hot index [0 or 1] of the count field
+	// below. Observe calls update the hot one. All remaining bits count the
+	// number of Observe calls. Observe starts by incrementing this counter,
+	// and finish by incrementing the count field in the respective
+	// summaryCounts, as a marker for completion.
+	//
+	// Calls of the Write method (which are non-mutating reads from the
+	// perspective of the summary) swap the hot–cold under the writeMtx
+	// lock. A cooldown is awaited (while locked) by comparing the number of
+	// observations with the initiation count. Once they match, then the
+	// last observation on the now cool one has completed. All cool fields must
+	// be merged into the new hot before releasing writeMtx.
+
+	// Fields with atomic access first! See alignment constraint:
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	countAndHotIdx uint64
+
+	selfCollector
+	desc     *Desc
+	writeMtx sync.Mutex // Only used in the Write method.
+
+	// Two counts, one is "hot" for lock-free observations, the other is
+	// "cold" for writing out a dto.Metric. It has to be an array of
+	// pointers to guarantee 64bit alignment of the histogramCounts, see
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG.
+	counts [2]*summaryCounts
+
+	labelPairs []*dto.LabelPair
+}
+
+func (s *noObjectivesSummary) Desc() *Desc {
+	return s.desc
+}
+
+func (s *noObjectivesSummary) Observe(v float64) {
+	// We increment h.countAndHotIdx so that the counter in the lower
+	// 63 bits gets incremented. At the same time, we get the new value
+	// back, which we can use to find the currently-hot counts.
+	n := atomic.AddUint64(&s.countAndHotIdx, 1)
+	hotCounts := s.counts[n>>63]
+
+	for {
+		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
+		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
+			break
+		}
+	}
+	// Increment count last as we take it as a signal that the observation
+	// is complete.
+	atomic.AddUint64(&hotCounts.count, 1)
+}
+
+func (s *noObjectivesSummary) Write(out *dto.Metric) error {
+	// For simplicity, we protect this whole method by a mutex. It is not in
+	// the hot path, i.e. Observe is called much more often than Write. The
+	// complication of making Write lock-free isn't worth it, if possible at
+	// all.
+	s.writeMtx.Lock()
+	defer s.writeMtx.Unlock()
+
+	// Adding 1<<63 switches the hot index (from 0 to 1 or from 1 to 0)
+	// without touching the count bits. See the struct comments for a full
+	// description of the algorithm.
+	n := atomic.AddUint64(&s.countAndHotIdx, 1<<63)
+	// count is contained unchanged in the lower 63 bits.
+	count := n & ((1 << 63) - 1)
+	// The most significant bit tells us which counts is hot. The complement
+	// is thus the cold one.
+	hotCounts := s.counts[n>>63]
+	coldCounts := s.counts[(^n)>>63]
+
+	// Await cooldown.
+	for count != atomic.LoadUint64(&coldCounts.count) {
+		runtime.Gosched() // Let observations get work done.
+	}
+
+	sum := &dto.Summary{
+		SampleCount: proto.Uint64(count),
+		SampleSum:   proto.Float64(math.Float64frombits(atomic.LoadUint64(&coldCounts.sumBits))),
+	}
+
+	out.Summary = sum
+	out.Label = s.labelPairs
+
+	// Finally add all the cold counts to the new hot counts and reset the cold counts.
+	atomic.AddUint64(&hotCounts.count, count)
+	atomic.StoreUint64(&coldCounts.count, 0)
+	for {
+		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + sum.GetSampleSum())
+		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
+			atomic.StoreUint64(&coldCounts.sumBits, 0)
+			break
+		}
+	}
+	return nil
+}
+
 type quantSort []*dto.Quantile
 
 func (s quantSort) Len() int {
@@ -390,13 +512,21 @@ func (s quantSort) Less(i, j int) bool {
 // (e.g. HTTP request latencies, partitioned by status code and method). Create
 // instances with NewSummaryVec.
 type SummaryVec struct {
-	*MetricVec
+	*metricVec
 }
 
 // NewSummaryVec creates a new SummaryVec based on the provided SummaryOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
+// partitioned by the given label names.
+//
+// Due to the way a Summary is represented in the Prometheus text format and how
+// it is handled by the Prometheus server internally, “quantile” is an illegal
+// label name. NewSummaryVec will panic if this label name is used.
 func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
+	for _, ln := range labelNames {
+		if ln == quantileLabel {
+			panic(errQuantileLabelNotAllowed)
+		}
+	}
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
@@ -404,47 +534,116 @@ func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
 		opts.ConstLabels,
 	)
 	return &SummaryVec{
-		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
+		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			return newSummary(desc, opts, lvs...)
 		}),
 	}
 }
 
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns a Summary and not a
-// Metric so that no type conversion is required.
-func (m *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Summary, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
+// GetMetricWithLabelValues returns the Summary for the given slice of label
+// values (same order as the VariableLabels in Desc). If that combination of
+// label values is accessed for the first time, a new Summary is created.
+//
+// It is possible to call this method without using the returned Summary to only
+// create the new Summary but leave it at its starting value, a Summary without
+// any observations.
+//
+// Keeping the Summary for later use is possible (and should be considered if
+// performance is critical), but keep in mind that Reset, DeleteLabelValues and
+// Delete can be used to delete the Summary from the SummaryVec. In that case,
+// the Summary will still exist, but it will not be exported anymore, even if a
+// Summary with the same label values is created later. See also the CounterVec
+// example.
+//
+// An error is returned if the number of label values is not the same as the
+// number of VariableLabels in Desc (minus any curried labels).
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
+// an alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
+// See also the GaugeVec example.
+func (v *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) {
+	metric, err := v.metricVec.getMetricWithLabelValues(lvs...)
 	if metric != nil {
-		return metric.(Summary), err
+		return metric.(Observer), err
 	}
 	return nil, err
 }
 
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns a Summary and not a Metric so that no
-// type conversion is required.
-func (m *SummaryVec) GetMetricWith(labels Labels) (Summary, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
+// GetMetricWith returns the Summary for the given Labels map (the label names
+// must match those of the VariableLabels in Desc). If that label map is
+// accessed for the first time, a new Summary is created. Implications of
+// creating a Summary without using it and keeping the Summary for later use are
+// the same as for GetMetricWithLabelValues.
+//
+// An error is returned if the number and names of the Labels are inconsistent
+// with those of the VariableLabels in Desc (minus any curried labels).
+//
+// This method is used for the same purpose as
+// GetMetricWithLabelValues(...string). See there for pros and cons of the two
+// methods.
+func (v *SummaryVec) GetMetricWith(labels Labels) (Observer, error) {
+	metric, err := v.metricVec.getMetricWith(labels)
 	if metric != nil {
-		return metric.(Summary), err
+		return metric.(Observer), err
 	}
 	return nil, err
 }
 
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
+// GetMetricWithLabelValues would have returned an error. Not returning an
+// error allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Observe(42.21)
-func (m *SummaryVec) WithLabelValues(lvs ...string) Summary {
-	return m.MetricVec.WithLabelValues(lvs...).(Summary)
+func (v *SummaryVec) WithLabelValues(lvs ...string) Observer {
+	s, err := v.GetMetricWithLabelValues(lvs...)
+	if err != nil {
+		panic(err)
+	}
+	return s
 }
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Observe(42.21)
-func (m *SummaryVec) With(labels Labels) Summary {
-	return m.MetricVec.With(labels).(Summary)
+// returned an error. Not returning an error allows shortcuts like
+//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Observe(42.21)
+func (v *SummaryVec) With(labels Labels) Observer {
+	s, err := v.GetMetricWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return s
+}
+
+// CurryWith returns a vector curried with the provided labels, i.e. the
+// returned vector has those labels pre-set for all labeled operations performed
+// on it. The cardinality of the curried vector is reduced accordingly. The
+// order of the remaining labels stays the same (just with the curried labels
+// taken out of the sequence – which is relevant for the
+// (GetMetric)WithLabelValues methods). It is possible to curry a curried
+// vector, but only with labels not yet used for currying before.
+//
+// The metrics contained in the SummaryVec are shared between the curried and
+// uncurried vectors. They are just accessed differently. Curried and uncurried
+// vectors behave identically in terms of collection. Only one must be
+// registered with a given registry (usually the uncurried version). The Reset
+// method deletes all metrics, even if called on a curried vector.
+func (v *SummaryVec) CurryWith(labels Labels) (ObserverVec, error) {
+	vec, err := v.curryWith(labels)
+	if vec != nil {
+		return &SummaryVec{vec}, err
+	}
+	return nil, err
+}
+
+// MustCurryWith works as CurryWith but panics where CurryWith would have
+// returned an error.
+func (v *SummaryVec) MustCurryWith(labels Labels) ObserverVec {
+	vec, err := v.CurryWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return vec
 }
 
 type constSummary struct {
@@ -497,7 +696,7 @@ func (s *constSummary) Write(out *dto.Metric) error {
 //     map[float64]float64{0.5: 0.23, 0.99: 0.56}
 //
 // NewConstSummary returns an error if the length of labelValues is not
-// consistent with the variable labels in Desc.
+// consistent with the variable labels in Desc or if Desc is invalid.
 func NewConstSummary(
 	desc *Desc,
 	count uint64,
@@ -505,8 +704,11 @@ func NewConstSummary(
 	quantiles map[float64]float64,
 	labelValues ...string,
 ) (Metric, error) {
-	if len(desc.variableLabels) != len(labelValues) {
-		return nil, errInconsistentCardinality
+	if desc.err != nil {
+		return nil, desc.err
+	}
+	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
+		return nil, err
 	}
 	return &constSummary{
 		desc:       desc,

vendor/github.com/prometheus/client_golang/prometheus/timer.go

@@ -0,0 +1,54 @@
+// Copyright 2016 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+import "time"
+
+// Timer is a helper type to time functions. Use NewTimer to create new
+// instances.
+type Timer struct {
+	begin    time.Time
+	observer Observer
+}
+
+// NewTimer creates a new Timer. The provided Observer is used to observe a
+// duration in seconds. Timer is usually used to time a function call in the
+// following way:
+//    func TimeMe() {
+//        timer := NewTimer(myHistogram)
+//        defer timer.ObserveDuration()
+//        // Do actual work.
+//    }
+func NewTimer(o Observer) *Timer {
+	return &Timer{
+		begin:    time.Now(),
+		observer: o,
+	}
+}
+
+// ObserveDuration records the duration passed since the Timer was created with
+// NewTimer. It calls the Observe method of the Observer provided during
+// construction with the duration in seconds as an argument. The observed
+// duration is also returned. ObserveDuration is usually called with a defer
+// statement.
+//
+// Note that this method is only guaranteed to never observe negative durations
+// if used with Go1.9+.
+func (t *Timer) ObserveDuration() time.Duration {
+	d := time.Since(t.begin)
+	if t.observer != nil {
+		t.observer.Observe(d.Seconds())
+	}
+	return d
+}

vendor/github.com/prometheus/client_golang/prometheus/untyped.go

@@ -13,108 +13,12 @@
 
 package prometheus
 
-// Untyped is a Metric that represents a single numerical value that can
-// arbitrarily go up and down.
-//
-// An Untyped metric works the same as a Gauge. The only difference is that to
-// no type information is implied.
-//
-// To create Untyped instances, use NewUntyped.
-type Untyped interface {
-	Metric
-	Collector
-
-	// Set sets the Untyped metric to an arbitrary value.
-	Set(float64)
-	// Inc increments the Untyped metric by 1.
-	Inc()
-	// Dec decrements the Untyped metric by 1.
-	Dec()
-	// Add adds the given value to the Untyped metric. (The value can be
-	// negative, resulting in a decrease.)
-	Add(float64)
-	// Sub subtracts the given value from the Untyped metric. (The value can
-	// be negative, resulting in an increase.)
-	Sub(float64)
-}
-
 // UntypedOpts is an alias for Opts. See there for doc comments.
 type UntypedOpts Opts
 
-// NewUntyped creates a new Untyped metric from the provided UntypedOpts.
-func NewUntyped(opts UntypedOpts) Untyped {
-	return newValue(NewDesc(
-		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
-		opts.Help,
-		nil,
-		opts.ConstLabels,
-	), UntypedValue, 0)
-}
-
-// UntypedVec is a Collector that bundles a set of Untyped metrics that all
-// share the same Desc, but have different values for their variable
-// labels. This is used if you want to count the same thing partitioned by
-// various dimensions. Create instances with NewUntypedVec.
-type UntypedVec struct {
-	*MetricVec
-}
-
-// NewUntypedVec creates a new UntypedVec based on the provided UntypedOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
-func NewUntypedVec(opts UntypedOpts, labelNames []string) *UntypedVec {
-	desc := NewDesc(
-		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
-		opts.Help,
-		labelNames,
-		opts.ConstLabels,
-	)
-	return &UntypedVec{
-		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
-			return newValue(desc, UntypedValue, 0, lvs...)
-		}),
-	}
-}
-
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns an Untyped and not a
-// Metric so that no type conversion is required.
-func (m *UntypedVec) GetMetricWithLabelValues(lvs ...string) (Untyped, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
-	if metric != nil {
-		return metric.(Untyped), err
-	}
-	return nil, err
-}
-
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns an Untyped and not a Metric so that no
-// type conversion is required.
-func (m *UntypedVec) GetMetricWith(labels Labels) (Untyped, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
-	if metric != nil {
-		return metric.(Untyped), err
-	}
-	return nil, err
-}
-
-// WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
-//     myVec.WithLabelValues("404", "GET").Add(42)
-func (m *UntypedVec) WithLabelValues(lvs ...string) Untyped {
-	return m.MetricVec.WithLabelValues(lvs...).(Untyped)
-}
-
-// With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
-func (m *UntypedVec) With(labels Labels) Untyped {
-	return m.MetricVec.With(labels).(Untyped)
-}
-
-// UntypedFunc is an Untyped whose value is determined at collect time by
-// calling a provided function.
+// UntypedFunc works like GaugeFunc but the collected metric is of type
+// "Untyped". UntypedFunc is useful to mirror an external metric of unknown
+// type.
 //
 // To create UntypedFunc instances, use NewUntypedFunc.
 type UntypedFunc interface {

vendor/github.com/prometheus/client_golang/prometheus/value.go

@@ -14,21 +14,22 @@
 package prometheus
 
 import (
-	"errors"
 	"fmt"
-	"math"
 	"sort"
-	"sync/atomic"
-
-	dto "github.com/prometheus/client_model/go"
+	"time"
+	"unicode/utf8"
 
 	"github.com/golang/protobuf/proto"
+	"github.com/golang/protobuf/ptypes"
+
+	dto "github.com/prometheus/client_model/go"
 )
 
 // ValueType is an enumeration of metric types that represent a simple value.
 type ValueType int
 
-// Possible values for the ValueType enum.
+// Possible values for the ValueType enum. Use UntypedValue to mark a metric
+// with an unknown type.
 const (
 	_ ValueType = iota
 	CounterValue
@@ -36,77 +37,6 @@ const (
 	UntypedValue
 )
 
-var errInconsistentCardinality = errors.New("inconsistent label cardinality")
-
-// value is a generic metric for simple values. It implements Metric, Collector,
-// Counter, Gauge, and Untyped. Its effective type is determined by
-// ValueType. This is a low-level building block used by the library to back the
-// implementations of Counter, Gauge, and Untyped.
-type value struct {
-	// valBits containst the bits of the represented float64 value. It has
-	// to go first in the struct to guarantee alignment for atomic
-	// operations.  http://golang.org/pkg/sync/atomic/#pkg-note-BUG
-	valBits uint64
-
-	selfCollector
-
-	desc       *Desc
-	valType    ValueType
-	labelPairs []*dto.LabelPair
-}
-
-// newValue returns a newly allocated value with the given Desc, ValueType,
-// sample value and label values. It panics if the number of label
-// values is different from the number of variable labels in Desc.
-func newValue(desc *Desc, valueType ValueType, val float64, labelValues ...string) *value {
-	if len(labelValues) != len(desc.variableLabels) {
-		panic(errInconsistentCardinality)
-	}
-	result := &value{
-		desc:       desc,
-		valType:    valueType,
-		valBits:    math.Float64bits(val),
-		labelPairs: makeLabelPairs(desc, labelValues),
-	}
-	result.init(result)
-	return result
-}
-
-func (v *value) Desc() *Desc {
-	return v.desc
-}
-
-func (v *value) Set(val float64) {
-	atomic.StoreUint64(&v.valBits, math.Float64bits(val))
-}
-
-func (v *value) Inc() {
-	v.Add(1)
-}
-
-func (v *value) Dec() {
-	v.Add(-1)
-}
-
-func (v *value) Add(val float64) {
-	for {
-		oldBits := atomic.LoadUint64(&v.valBits)
-		newBits := math.Float64bits(math.Float64frombits(oldBits) + val)
-		if atomic.CompareAndSwapUint64(&v.valBits, oldBits, newBits) {
-			return
-		}
-	}
-}
-
-func (v *value) Sub(val float64) {
-	v.Add(val * -1)
-}
-
-func (v *value) Write(out *dto.Metric) error {
-	val := math.Float64frombits(atomic.LoadUint64(&v.valBits))
-	return populateMetric(v.valType, val, v.labelPairs, out)
-}
-
 // valueFunc is a generic metric for simple values retrieved on collect time
 // from a function. It implements Metric and Collector. Its effective type is
 // determined by ValueType. This is a low-level building block used by the
@@ -143,7 +73,7 @@ func (v *valueFunc) Desc() *Desc {
 }
 
 func (v *valueFunc) Write(out *dto.Metric) error {
-	return populateMetric(v.valType, v.function(), v.labelPairs, out)
+	return populateMetric(v.valType, v.function(), v.labelPairs, nil, out)
 }
 
 // NewConstMetric returns a metric with one fixed value that cannot be
@@ -151,10 +81,14 @@ func (v *valueFunc) Write(out *dto.Metric) error {
 // operations. However, when implementing custom Collectors, it is useful as a
 // throw-away metric that is generated on the fly to send it to Prometheus in
 // the Collect method. NewConstMetric returns an error if the length of
-// labelValues is not consistent with the variable labels in Desc.
+// labelValues is not consistent with the variable labels in Desc or if Desc is
+// invalid.
 func NewConstMetric(desc *Desc, valueType ValueType, value float64, labelValues ...string) (Metric, error) {
-	if len(desc.variableLabels) != len(labelValues) {
-		return nil, errInconsistentCardinality
+	if desc.err != nil {
+		return nil, desc.err
+	}
+	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
+		return nil, err
 	}
 	return &constMetric{
 		desc:       desc,
@@ -186,19 +120,20 @@ func (m *constMetric) Desc() *Desc {
 }
 
 func (m *constMetric) Write(out *dto.Metric) error {
-	return populateMetric(m.valType, m.val, m.labelPairs, out)
+	return populateMetric(m.valType, m.val, m.labelPairs, nil, out)
 }
 
 func populateMetric(
 	t ValueType,
 	v float64,
 	labelPairs []*dto.LabelPair,
+	e *dto.Exemplar,
 	m *dto.Metric,
 ) error {
 	m.Label = labelPairs
 	switch t {
 	case CounterValue:
-		m.Counter = &dto.Counter{Value: proto.Float64(v)}
+		m.Counter = &dto.Counter{Value: proto.Float64(v), Exemplar: e}
 	case GaugeValue:
 		m.Gauge = &dto.Gauge{Value: proto.Float64(v)}
 	case UntypedValue:
@@ -226,9 +161,44 @@ func makeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair {
 			Value: proto.String(labelValues[i]),
 		})
 	}
-	for _, lp := range desc.constLabelPairs {
-		labelPairs = append(labelPairs, lp)
-	}
-	sort.Sort(LabelPairSorter(labelPairs))
+	labelPairs = append(labelPairs, desc.constLabelPairs...)
+	sort.Sort(labelPairSorter(labelPairs))
 	return labelPairs
 }
+
+// ExemplarMaxRunes is the max total number of runes allowed in exemplar labels.
+const ExemplarMaxRunes = 64
+
+// newExemplar creates a new dto.Exemplar from the provided values. An error is
+// returned if any of the label names or values are invalid or if the total
+// number of runes in the label names and values exceeds ExemplarMaxRunes.
+func newExemplar(value float64, ts time.Time, l Labels) (*dto.Exemplar, error) {
+	e := &dto.Exemplar{}
+	e.Value = proto.Float64(value)
+	tsProto, err := ptypes.TimestampProto(ts)
+	if err != nil {
+		return nil, err
+	}
+	e.Timestamp = tsProto
+	labelPairs := make([]*dto.LabelPair, 0, len(l))
+	var runes int
+	for name, value := range l {
+		if !checkLabelName(name) {
+			return nil, fmt.Errorf("exemplar label name %q is invalid", name)
+		}
+		runes += utf8.RuneCountInString(name)
+		if !utf8.ValidString(value) {
+			return nil, fmt.Errorf("exemplar label value %q is not valid UTF-8", value)
+		}
+		runes += utf8.RuneCountInString(value)
+		labelPairs = append(labelPairs, &dto.LabelPair{
+			Name:  proto.String(name),
+			Value: proto.String(value),
+		})
+	}
+	if runes > ExemplarMaxRunes {
+		return nil, fmt.Errorf("exemplar labels have %d runes, exceeding the limit of %d", runes, ExemplarMaxRunes)
+	}
+	e.Label = labelPairs
+	return e, nil
+}

vendor/github.com/prometheus/client_golang/prometheus/vec.go

@@ -20,33 +20,192 @@ import (
 	"github.com/prometheus/common/model"
 )
 
-// MetricVec is a Collector to bundle metrics of the same name that
-// differ in their label values. MetricVec is usually not used directly but as a
-// building block for implementations of vectors of a given metric
-// type. GaugeVec, CounterVec, SummaryVec, and UntypedVec are examples already
-// provided in this package.
-type MetricVec struct {
-	mtx      sync.RWMutex // Protects the children.
-	children map[uint64][]metricWithLabelValues
-	desc     *Desc
+// metricVec is a Collector to bundle metrics of the same name that differ in
+// their label values. metricVec is not used directly (and therefore
+// unexported). It is used as a building block for implementations of vectors of
+// a given metric type, like GaugeVec, CounterVec, SummaryVec, and HistogramVec.
+// It also handles label currying.
+type metricVec struct {
+	*metricMap
 
-	newMetric   func(labelValues ...string) Metric
-	hashAdd     func(h uint64, s string) uint64 // replace hash function for testing collision handling
+	curry []curriedLabelValue
+
+	// hashAdd and hashAddByte can be replaced for testing collision handling.
+	hashAdd     func(h uint64, s string) uint64
 	hashAddByte func(h uint64, b byte) uint64
 }
 
-// newMetricVec returns an initialized MetricVec. The concrete value is
-// returned for embedding into another struct.
-func newMetricVec(desc *Desc, newMetric func(lvs ...string) Metric) *MetricVec {
-	return &MetricVec{
-		children:    map[uint64][]metricWithLabelValues{},
-		desc:        desc,
-		newMetric:   newMetric,
+// newMetricVec returns an initialized metricVec.
+func newMetricVec(desc *Desc, newMetric func(lvs ...string) Metric) *metricVec {
+	return &metricVec{
+		metricMap: &metricMap{
+			metrics:   map[uint64][]metricWithLabelValues{},
+			desc:      desc,
+			newMetric: newMetric,
+		},
 		hashAdd:     hashAdd,
 		hashAddByte: hashAddByte,
 	}
 }
 
+// DeleteLabelValues removes the metric where the variable labels are the same
+// as those passed in as labels (same order as the VariableLabels in Desc). It
+// returns true if a metric was deleted.
+//
+// It is not an error if the number of label values is not the same as the
+// number of VariableLabels in Desc. However, such inconsistent label count can
+// never match an actual metric, so the method will always return false in that
+// case.
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider Delete(Labels) as an
+// alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
+// See also the CounterVec example.
+func (m *metricVec) DeleteLabelValues(lvs ...string) bool {
+	h, err := m.hashLabelValues(lvs)
+	if err != nil {
+		return false
+	}
+
+	return m.metricMap.deleteByHashWithLabelValues(h, lvs, m.curry)
+}
+
+// Delete deletes the metric where the variable labels are the same as those
+// passed in as labels. It returns true if a metric was deleted.
+//
+// It is not an error if the number and names of the Labels are inconsistent
+// with those of the VariableLabels in Desc. However, such inconsistent Labels
+// can never match an actual metric, so the method will always return false in
+// that case.
+//
+// This method is used for the same purpose as DeleteLabelValues(...string). See
+// there for pros and cons of the two methods.
+func (m *metricVec) Delete(labels Labels) bool {
+	h, err := m.hashLabels(labels)
+	if err != nil {
+		return false
+	}
+
+	return m.metricMap.deleteByHashWithLabels(h, labels, m.curry)
+}
+
+// Without explicit forwarding of Describe, Collect, Reset, those methods won't
+// show up in GoDoc.
+
+// Describe implements Collector.
+func (m *metricVec) Describe(ch chan<- *Desc) { m.metricMap.Describe(ch) }
+
+// Collect implements Collector.
+func (m *metricVec) Collect(ch chan<- Metric) { m.metricMap.Collect(ch) }
+
+// Reset deletes all metrics in this vector.
+func (m *metricVec) Reset() { m.metricMap.Reset() }
+
+func (m *metricVec) curryWith(labels Labels) (*metricVec, error) {
+	var (
+		newCurry []curriedLabelValue
+		oldCurry = m.curry
+		iCurry   int
+	)
+	for i, label := range m.desc.variableLabels {
+		val, ok := labels[label]
+		if iCurry < len(oldCurry) && oldCurry[iCurry].index == i {
+			if ok {
+				return nil, fmt.Errorf("label name %q is already curried", label)
+			}
+			newCurry = append(newCurry, oldCurry[iCurry])
+			iCurry++
+		} else {
+			if !ok {
+				continue // Label stays uncurried.
+			}
+			newCurry = append(newCurry, curriedLabelValue{i, val})
+		}
+	}
+	if l := len(oldCurry) + len(labels) - len(newCurry); l > 0 {
+		return nil, fmt.Errorf("%d unknown label(s) found during currying", l)
+	}
+
+	return &metricVec{
+		metricMap:   m.metricMap,
+		curry:       newCurry,
+		hashAdd:     m.hashAdd,
+		hashAddByte: m.hashAddByte,
+	}, nil
+}
+
+func (m *metricVec) getMetricWithLabelValues(lvs ...string) (Metric, error) {
+	h, err := m.hashLabelValues(lvs)
+	if err != nil {
+		return nil, err
+	}
+
+	return m.metricMap.getOrCreateMetricWithLabelValues(h, lvs, m.curry), nil
+}
+
+func (m *metricVec) getMetricWith(labels Labels) (Metric, error) {
+	h, err := m.hashLabels(labels)
+	if err != nil {
+		return nil, err
+	}
+
+	return m.metricMap.getOrCreateMetricWithLabels(h, labels, m.curry), nil
+}
+
+func (m *metricVec) hashLabelValues(vals []string) (uint64, error) {
+	if err := validateLabelValues(vals, len(m.desc.variableLabels)-len(m.curry)); err != nil {
+		return 0, err
+	}
+
+	var (
+		h             = hashNew()
+		curry         = m.curry
+		iVals, iCurry int
+	)
+	for i := 0; i < len(m.desc.variableLabels); i++ {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			h = m.hashAdd(h, curry[iCurry].value)
+			iCurry++
+		} else {
+			h = m.hashAdd(h, vals[iVals])
+			iVals++
+		}
+		h = m.hashAddByte(h, model.SeparatorByte)
+	}
+	return h, nil
+}
+
+func (m *metricVec) hashLabels(labels Labels) (uint64, error) {
+	if err := validateValuesInLabels(labels, len(m.desc.variableLabels)-len(m.curry)); err != nil {
+		return 0, err
+	}
+
+	var (
+		h      = hashNew()
+		curry  = m.curry
+		iCurry int
+	)
+	for i, label := range m.desc.variableLabels {
+		val, ok := labels[label]
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			if ok {
+				return 0, fmt.Errorf("label name %q is already curried", label)
+			}
+			h = m.hashAdd(h, curry[iCurry].value)
+			iCurry++
+		} else {
+			if !ok {
+				return 0, fmt.Errorf("label name %q missing in label map", label)
+			}
+			h = m.hashAdd(h, val)
+		}
+		h = m.hashAddByte(h, model.SeparatorByte)
+	}
+	return h, nil
+}
+
 // metricWithLabelValues provides the metric and its label values for
 // disambiguation on hash collision.
 type metricWithLabelValues struct {
@@ -54,166 +213,72 @@ type metricWithLabelValues struct {
 	metric Metric
 }
 
-// Describe implements Collector. The length of the returned slice
-// is always one.
-func (m *MetricVec) Describe(ch chan<- *Desc) {
+// curriedLabelValue sets the curried value for a label at the given index.
+type curriedLabelValue struct {
+	index int
+	value string
+}
+
+// metricMap is a helper for metricVec and shared between differently curried
+// metricVecs.
+type metricMap struct {
+	mtx       sync.RWMutex // Protects metrics.
+	metrics   map[uint64][]metricWithLabelValues
+	desc      *Desc
+	newMetric func(labelValues ...string) Metric
+}
+
+// Describe implements Collector. It will send exactly one Desc to the provided
+// channel.
+func (m *metricMap) Describe(ch chan<- *Desc) {
 	ch <- m.desc
 }
 
 // Collect implements Collector.
-func (m *MetricVec) Collect(ch chan<- Metric) {
+func (m *metricMap) Collect(ch chan<- Metric) {
 	m.mtx.RLock()
 	defer m.mtx.RUnlock()
 
-	for _, metrics := range m.children {
+	for _, metrics := range m.metrics {
 		for _, metric := range metrics {
 			ch <- metric.metric
 		}
 	}
 }
 
-// GetMetricWithLabelValues returns the Metric for the given slice of label
-// values (same order as the VariableLabels in Desc). If that combination of
-// label values is accessed for the first time, a new Metric is created.
-//
-// It is possible to call this method without using the returned Metric to only
-// create the new Metric but leave it at its start value (e.g. a Summary or
-// Histogram without any observations). See also the SummaryVec example.
-//
-// Keeping the Metric for later use is possible (and should be considered if
-// performance is critical), but keep in mind that Reset, DeleteLabelValues and
-// Delete can be used to delete the Metric from the MetricVec. In that case, the
-// Metric will still exist, but it will not be exported anymore, even if a
-// Metric with the same label values is created later. See also the CounterVec
-// example.
-//
-// An error is returned if the number of label values is not the same as the
-// number of VariableLabels in Desc.
-//
-// Note that for more than one label value, this method is prone to mistakes
-// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
-// an alternative to avoid that type of mistake. For higher label numbers, the
-// latter has a much more readable (albeit more verbose) syntax, but it comes
-// with a performance overhead (for creating and processing the Labels map).
-// See also the GaugeVec example.
-func (m *MetricVec) GetMetricWithLabelValues(lvs ...string) (Metric, error) {
-	h, err := m.hashLabelValues(lvs)
-	if err != nil {
-		return nil, err
-	}
-
-	return m.getOrCreateMetricWithLabelValues(h, lvs), nil
-}
-
-// GetMetricWith returns the Metric for the given Labels map (the label names
-// must match those of the VariableLabels in Desc). If that label map is
-// accessed for the first time, a new Metric is created. Implications of
-// creating a Metric without using it and keeping the Metric for later use are
-// the same as for GetMetricWithLabelValues.
-//
-// An error is returned if the number and names of the Labels are inconsistent
-// with those of the VariableLabels in Desc.
-//
-// This method is used for the same purpose as
-// GetMetricWithLabelValues(...string). See there for pros and cons of the two
-// methods.
-func (m *MetricVec) GetMetricWith(labels Labels) (Metric, error) {
-	h, err := m.hashLabels(labels)
-	if err != nil {
-		return nil, err
-	}
-
-	return m.getOrCreateMetricWithLabels(h, labels), nil
-}
-
-// WithLabelValues works as GetMetricWithLabelValues, but panics if an error
-// occurs. The method allows neat syntax like:
-//     httpReqs.WithLabelValues("404", "POST").Inc()
-func (m *MetricVec) WithLabelValues(lvs ...string) Metric {
-	metric, err := m.GetMetricWithLabelValues(lvs...)
-	if err != nil {
-		panic(err)
-	}
-	return metric
-}
-
-// With works as GetMetricWith, but panics if an error occurs. The method allows
-// neat syntax like:
-//     httpReqs.With(Labels{"status":"404", "method":"POST"}).Inc()
-func (m *MetricVec) With(labels Labels) Metric {
-	metric, err := m.GetMetricWith(labels)
-	if err != nil {
-		panic(err)
-	}
-	return metric
-}
-
-// DeleteLabelValues removes the metric where the variable labels are the same
-// as those passed in as labels (same order as the VariableLabels in Desc). It
-// returns true if a metric was deleted.
-//
-// It is not an error if the number of label values is not the same as the
-// number of VariableLabels in Desc.  However, such inconsistent label count can
-// never match an actual Metric, so the method will always return false in that
-// case.
-//
-// Note that for more than one label value, this method is prone to mistakes
-// caused by an incorrect order of arguments. Consider Delete(Labels) as an
-// alternative to avoid that type of mistake. For higher label numbers, the
-// latter has a much more readable (albeit more verbose) syntax, but it comes
-// with a performance overhead (for creating and processing the Labels map).
-// See also the CounterVec example.
-func (m *MetricVec) DeleteLabelValues(lvs ...string) bool {
+// Reset deletes all metrics in this vector.
+func (m *metricMap) Reset() {
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
 
-	h, err := m.hashLabelValues(lvs)
-	if err != nil {
-		return false
+	for h := range m.metrics {
+		delete(m.metrics, h)
 	}
-	return m.deleteByHashWithLabelValues(h, lvs)
-}
-
-// Delete deletes the metric where the variable labels are the same as those
-// passed in as labels. It returns true if a metric was deleted.
-//
-// It is not an error if the number and names of the Labels are inconsistent
-// with those of the VariableLabels in the Desc of the MetricVec. However, such
-// inconsistent Labels can never match an actual Metric, so the method will
-// always return false in that case.
-//
-// This method is used for the same purpose as DeleteLabelValues(...string). See
-// there for pros and cons of the two methods.
-func (m *MetricVec) Delete(labels Labels) bool {
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-
-	h, err := m.hashLabels(labels)
-	if err != nil {
-		return false
-	}
-
-	return m.deleteByHashWithLabels(h, labels)
 }
 
 // deleteByHashWithLabelValues removes the metric from the hash bucket h. If
 // there are multiple matches in the bucket, use lvs to select a metric and
 // remove only that metric.
-func (m *MetricVec) deleteByHashWithLabelValues(h uint64, lvs []string) bool {
-	metrics, ok := m.children[h]
+func (m *metricMap) deleteByHashWithLabelValues(
+	h uint64, lvs []string, curry []curriedLabelValue,
+) bool {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	metrics, ok := m.metrics[h]
 	if !ok {
 		return false
 	}
 
-	i := m.findMetricWithLabelValues(metrics, lvs)
+	i := findMetricWithLabelValues(metrics, lvs, curry)
 	if i >= len(metrics) {
 		return false
 	}
 
 	if len(metrics) > 1 {
-		m.children[h] = append(metrics[:i], metrics[i+1:]...)
+		m.metrics[h] = append(metrics[:i], metrics[i+1:]...)
 	} else {
-		delete(m.children, h)
+		delete(m.metrics, h)
 	}
 	return true
 }
@@ -221,69 +286,38 @@ func (m *MetricVec) deleteByHashWithLabelValues(h uint64, lvs []string) bool {
 // deleteByHashWithLabels removes the metric from the hash bucket h. If there
 // are multiple matches in the bucket, use lvs to select a metric and remove
 // only that metric.
-func (m *MetricVec) deleteByHashWithLabels(h uint64, labels Labels) bool {
-	metrics, ok := m.children[h]
+func (m *metricMap) deleteByHashWithLabels(
+	h uint64, labels Labels, curry []curriedLabelValue,
+) bool {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	metrics, ok := m.metrics[h]
 	if !ok {
 		return false
 	}
-	i := m.findMetricWithLabels(metrics, labels)
+	i := findMetricWithLabels(m.desc, metrics, labels, curry)
 	if i >= len(metrics) {
 		return false
 	}
 
 	if len(metrics) > 1 {
-		m.children[h] = append(metrics[:i], metrics[i+1:]...)
+		m.metrics[h] = append(metrics[:i], metrics[i+1:]...)
 	} else {
-		delete(m.children, h)
+		delete(m.metrics, h)
 	}
 	return true
 }
 
-// Reset deletes all metrics in this vector.
-func (m *MetricVec) Reset() {
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-
-	for h := range m.children {
-		delete(m.children, h)
-	}
-}
-
-func (m *MetricVec) hashLabelValues(vals []string) (uint64, error) {
-	if len(vals) != len(m.desc.variableLabels) {
-		return 0, errInconsistentCardinality
-	}
-	h := hashNew()
-	for _, val := range vals {
-		h = m.hashAdd(h, val)
-		h = m.hashAddByte(h, model.SeparatorByte)
-	}
-	return h, nil
-}
-
-func (m *MetricVec) hashLabels(labels Labels) (uint64, error) {
-	if len(labels) != len(m.desc.variableLabels) {
-		return 0, errInconsistentCardinality
-	}
-	h := hashNew()
-	for _, label := range m.desc.variableLabels {
-		val, ok := labels[label]
-		if !ok {
-			return 0, fmt.Errorf("label name %q missing in label map", label)
-		}
-		h = m.hashAdd(h, val)
-		h = m.hashAddByte(h, model.SeparatorByte)
-	}
-	return h, nil
-}
-
 // getOrCreateMetricWithLabelValues retrieves the metric by hash and label value
 // or creates it and returns the new one.
 //
 // This function holds the mutex.
-func (m *MetricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string) Metric {
+func (m *metricMap) getOrCreateMetricWithLabelValues(
+	hash uint64, lvs []string, curry []curriedLabelValue,
+) Metric {
 	m.mtx.RLock()
-	metric, ok := m.getMetricWithLabelValues(hash, lvs)
+	metric, ok := m.getMetricWithHashAndLabelValues(hash, lvs, curry)
 	m.mtx.RUnlock()
 	if ok {
 		return metric
@@ -291,13 +325,11 @@ func (m *MetricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string)
 
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
-	metric, ok = m.getMetricWithLabelValues(hash, lvs)
+	metric, ok = m.getMetricWithHashAndLabelValues(hash, lvs, curry)
 	if !ok {
-		// Copy to avoid allocation in case wo don't go down this code path.
-		copiedLVs := make([]string, len(lvs))
-		copy(copiedLVs, lvs)
-		metric = m.newMetric(copiedLVs...)
-		m.children[hash] = append(m.children[hash], metricWithLabelValues{values: copiedLVs, metric: metric})
+		inlinedLVs := inlineLabelValues(lvs, curry)
+		metric = m.newMetric(inlinedLVs...)
+		m.metrics[hash] = append(m.metrics[hash], metricWithLabelValues{values: inlinedLVs, metric: metric})
 	}
 	return metric
 }
@@ -306,9 +338,11 @@ func (m *MetricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string)
 // or creates it and returns the new one.
 //
 // This function holds the mutex.
-func (m *MetricVec) getOrCreateMetricWithLabels(hash uint64, labels Labels) Metric {
+func (m *metricMap) getOrCreateMetricWithLabels(
+	hash uint64, labels Labels, curry []curriedLabelValue,
+) Metric {
 	m.mtx.RLock()
-	metric, ok := m.getMetricWithLabels(hash, labels)
+	metric, ok := m.getMetricWithHashAndLabels(hash, labels, curry)
 	m.mtx.RUnlock()
 	if ok {
 		return metric
@@ -316,33 +350,37 @@ func (m *MetricVec) getOrCreateMetricWithLabels(hash uint64, labels Labels) Metr
 
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
-	metric, ok = m.getMetricWithLabels(hash, labels)
+	metric, ok = m.getMetricWithHashAndLabels(hash, labels, curry)
 	if !ok {
-		lvs := m.extractLabelValues(labels)
+		lvs := extractLabelValues(m.desc, labels, curry)
 		metric = m.newMetric(lvs...)
-		m.children[hash] = append(m.children[hash], metricWithLabelValues{values: lvs, metric: metric})
+		m.metrics[hash] = append(m.metrics[hash], metricWithLabelValues{values: lvs, metric: metric})
 	}
 	return metric
 }
 
-// getMetricWithLabelValues gets a metric while handling possible collisions in
-// the hash space. Must be called while holding read mutex.
-func (m *MetricVec) getMetricWithLabelValues(h uint64, lvs []string) (Metric, bool) {
-	metrics, ok := m.children[h]
+// getMetricWithHashAndLabelValues gets a metric while handling possible
+// collisions in the hash space. Must be called while holding the read mutex.
+func (m *metricMap) getMetricWithHashAndLabelValues(
+	h uint64, lvs []string, curry []curriedLabelValue,
+) (Metric, bool) {
+	metrics, ok := m.metrics[h]
 	if ok {
-		if i := m.findMetricWithLabelValues(metrics, lvs); i < len(metrics) {
+		if i := findMetricWithLabelValues(metrics, lvs, curry); i < len(metrics) {
 			return metrics[i].metric, true
 		}
 	}
 	return nil, false
 }
 
-// getMetricWithLabels gets a metric while handling possible collisions in
+// getMetricWithHashAndLabels gets a metric while handling possible collisions in
 // the hash space. Must be called while holding read mutex.
-func (m *MetricVec) getMetricWithLabels(h uint64, labels Labels) (Metric, bool) {
-	metrics, ok := m.children[h]
+func (m *metricMap) getMetricWithHashAndLabels(
+	h uint64, labels Labels, curry []curriedLabelValue,
+) (Metric, bool) {
+	metrics, ok := m.metrics[h]
 	if ok {
-		if i := m.findMetricWithLabels(metrics, labels); i < len(metrics) {
+		if i := findMetricWithLabels(m.desc, metrics, labels, curry); i < len(metrics) {
 			return metrics[i].metric, true
 		}
 	}
@@ -351,9 +389,11 @@ func (m *MetricVec) getMetricWithLabels(h uint64, labels Labels) (Metric, bool)
 
 // findMetricWithLabelValues returns the index of the matching metric or
 // len(metrics) if not found.
-func (m *MetricVec) findMetricWithLabelValues(metrics []metricWithLabelValues, lvs []string) int {
+func findMetricWithLabelValues(
+	metrics []metricWithLabelValues, lvs []string, curry []curriedLabelValue,
+) int {
 	for i, metric := range metrics {
-		if m.matchLabelValues(metric.values, lvs) {
+		if matchLabelValues(metric.values, lvs, curry) {
 			return i
 		}
 	}
@@ -362,32 +402,51 @@ func (m *MetricVec) findMetricWithLabelValues(metrics []metricWithLabelValues, l
 
 // findMetricWithLabels returns the index of the matching metric or len(metrics)
 // if not found.
-func (m *MetricVec) findMetricWithLabels(metrics []metricWithLabelValues, labels Labels) int {
+func findMetricWithLabels(
+	desc *Desc, metrics []metricWithLabelValues, labels Labels, curry []curriedLabelValue,
+) int {
 	for i, metric := range metrics {
-		if m.matchLabels(metric.values, labels) {
+		if matchLabels(desc, metric.values, labels, curry) {
 			return i
 		}
 	}
 	return len(metrics)
 }
 
-func (m *MetricVec) matchLabelValues(values []string, lvs []string) bool {
-	if len(values) != len(lvs) {
+func matchLabelValues(values []string, lvs []string, curry []curriedLabelValue) bool {
+	if len(values) != len(lvs)+len(curry) {
 		return false
 	}
+	var iLVs, iCurry int
 	for i, v := range values {
-		if v != lvs[i] {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			if v != curry[iCurry].value {
+				return false
+			}
+			iCurry++
+			continue
+		}
+		if v != lvs[iLVs] {
 			return false
 		}
+		iLVs++
 	}
 	return true
 }
 
-func (m *MetricVec) matchLabels(values []string, labels Labels) bool {
-	if len(labels) != len(values) {
+func matchLabels(desc *Desc, values []string, labels Labels, curry []curriedLabelValue) bool {
+	if len(values) != len(labels)+len(curry) {
 		return false
 	}
-	for i, k := range m.desc.variableLabels {
+	iCurry := 0
+	for i, k := range desc.variableLabels {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			if values[i] != curry[iCurry].value {
+				return false
+			}
+			iCurry++
+			continue
+		}
 		if values[i] != labels[k] {
 			return false
 		}
@@ -395,10 +454,31 @@ func (m *MetricVec) matchLabels(values []string, labels Labels) bool {
 	return true
 }
 
-func (m *MetricVec) extractLabelValues(labels Labels) []string {
-	labelValues := make([]string, len(labels))
-	for i, k := range m.desc.variableLabels {
+func extractLabelValues(desc *Desc, labels Labels, curry []curriedLabelValue) []string {
+	labelValues := make([]string, len(labels)+len(curry))
+	iCurry := 0
+	for i, k := range desc.variableLabels {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			labelValues[i] = curry[iCurry].value
+			iCurry++
+			continue
+		}
 		labelValues[i] = labels[k]
 	}
 	return labelValues
 }
+
+func inlineLabelValues(lvs []string, curry []curriedLabelValue) []string {
+	labelValues := make([]string, len(lvs)+len(curry))
+	var iCurry, iLVs int
+	for i := range labelValues {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			labelValues[i] = curry[iCurry].value
+			iCurry++
+			continue
+		}
+		labelValues[i] = lvs[iLVs]
+		iLVs++
+	}
+	return labelValues
+}

vendor/github.com/prometheus/client_golang/prometheus/wrap.go

@@ -0,0 +1,200 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+import (
+	"fmt"
+	"sort"
+
+	"github.com/golang/protobuf/proto"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
+// WrapRegistererWith returns a Registerer wrapping the provided
+// Registerer. Collectors registered with the returned Registerer will be
+// registered with the wrapped Registerer in a modified way. The modified
+// Collector adds the provided Labels to all Metrics it collects (as
+// ConstLabels). The Metrics collected by the unmodified Collector must not
+// duplicate any of those labels.
+//
+// WrapRegistererWith provides a way to add fixed labels to a subset of
+// Collectors. It should not be used to add fixed labels to all metrics exposed.
+//
+// Conflicts between Collectors registered through the original Registerer with
+// Collectors registered through the wrapping Registerer will still be
+// detected. Any AlreadyRegisteredError returned by the Register method of
+// either Registerer will contain the ExistingCollector in the form it was
+// provided to the respective registry.
+//
+// The Collector example demonstrates a use of WrapRegistererWith.
+func WrapRegistererWith(labels Labels, reg Registerer) Registerer {
+	return &wrappingRegisterer{
+		wrappedRegisterer: reg,
+		labels:            labels,
+	}
+}
+
+// WrapRegistererWithPrefix returns a Registerer wrapping the provided
+// Registerer. Collectors registered with the returned Registerer will be
+// registered with the wrapped Registerer in a modified way. The modified
+// Collector adds the provided prefix to the name of all Metrics it collects.
+//
+// WrapRegistererWithPrefix is useful to have one place to prefix all metrics of
+// a sub-system. To make this work, register metrics of the sub-system with the
+// wrapping Registerer returned by WrapRegistererWithPrefix. It is rarely useful
+// to use the same prefix for all metrics exposed. In particular, do not prefix
+// metric names that are standardized across applications, as that would break
+// horizontal monitoring, for example the metrics provided by the Go collector
+// (see NewGoCollector) and the process collector (see NewProcessCollector). (In
+// fact, those metrics are already prefixed with “go_” or “process_”,
+// respectively.)
+//
+// Conflicts between Collectors registered through the original Registerer with
+// Collectors registered through the wrapping Registerer will still be
+// detected. Any AlreadyRegisteredError returned by the Register method of
+// either Registerer will contain the ExistingCollector in the form it was
+// provided to the respective registry.
+func WrapRegistererWithPrefix(prefix string, reg Registerer) Registerer {
+	return &wrappingRegisterer{
+		wrappedRegisterer: reg,
+		prefix:            prefix,
+	}
+}
+
+type wrappingRegisterer struct {
+	wrappedRegisterer Registerer
+	prefix            string
+	labels            Labels
+}
+
+func (r *wrappingRegisterer) Register(c Collector) error {
+	return r.wrappedRegisterer.Register(&wrappingCollector{
+		wrappedCollector: c,
+		prefix:           r.prefix,
+		labels:           r.labels,
+	})
+}
+
+func (r *wrappingRegisterer) MustRegister(cs ...Collector) {
+	for _, c := range cs {
+		if err := r.Register(c); err != nil {
+			panic(err)
+		}
+	}
+}
+
+func (r *wrappingRegisterer) Unregister(c Collector) bool {
+	return r.wrappedRegisterer.Unregister(&wrappingCollector{
+		wrappedCollector: c,
+		prefix:           r.prefix,
+		labels:           r.labels,
+	})
+}
+
+type wrappingCollector struct {
+	wrappedCollector Collector
+	prefix           string
+	labels           Labels
+}
+
+func (c *wrappingCollector) Collect(ch chan<- Metric) {
+	wrappedCh := make(chan Metric)
+	go func() {
+		c.wrappedCollector.Collect(wrappedCh)
+		close(wrappedCh)
+	}()
+	for m := range wrappedCh {
+		ch <- &wrappingMetric{
+			wrappedMetric: m,
+			prefix:        c.prefix,
+			labels:        c.labels,
+		}
+	}
+}
+
+func (c *wrappingCollector) Describe(ch chan<- *Desc) {
+	wrappedCh := make(chan *Desc)
+	go func() {
+		c.wrappedCollector.Describe(wrappedCh)
+		close(wrappedCh)
+	}()
+	for desc := range wrappedCh {
+		ch <- wrapDesc(desc, c.prefix, c.labels)
+	}
+}
+
+func (c *wrappingCollector) unwrapRecursively() Collector {
+	switch wc := c.wrappedCollector.(type) {
+	case *wrappingCollector:
+		return wc.unwrapRecursively()
+	default:
+		return wc
+	}
+}
+
+type wrappingMetric struct {
+	wrappedMetric Metric
+	prefix        string
+	labels        Labels
+}
+
+func (m *wrappingMetric) Desc() *Desc {
+	return wrapDesc(m.wrappedMetric.Desc(), m.prefix, m.labels)
+}
+
+func (m *wrappingMetric) Write(out *dto.Metric) error {
+	if err := m.wrappedMetric.Write(out); err != nil {
+		return err
+	}
+	if len(m.labels) == 0 {
+		// No wrapping labels.
+		return nil
+	}
+	for ln, lv := range m.labels {
+		out.Label = append(out.Label, &dto.LabelPair{
+			Name:  proto.String(ln),
+			Value: proto.String(lv),
+		})
+	}
+	sort.Sort(labelPairSorter(out.Label))
+	return nil
+}
+
+func wrapDesc(desc *Desc, prefix string, labels Labels) *Desc {
+	constLabels := Labels{}
+	for _, lp := range desc.constLabelPairs {
+		constLabels[*lp.Name] = *lp.Value
+	}
+	for ln, lv := range labels {
+		if _, alreadyUsed := constLabels[ln]; alreadyUsed {
+			return &Desc{
+				fqName:          desc.fqName,
+				help:            desc.help,
+				variableLabels:  desc.variableLabels,
+				constLabelPairs: desc.constLabelPairs,
+				err:             fmt.Errorf("attempted wrapping with already existing label name %q", ln),
+			}
+		}
+		constLabels[ln] = lv
+	}
+	// NewDesc will do remaining validations.
+	newDesc := NewDesc(prefix+desc.fqName, desc.help, desc.variableLabels, constLabels)
+	// Propagate errors if there was any. This will override any errer
+	// created by NewDesc above, i.e. earlier errors get precedence.
+	if desc.err != nil {
+		newDesc.err = desc.err
+	}
+	return newDesc
+}

vendor/github.com/prometheus/client_model/README.md

@@ -1,26 +1,34 @@
-# Background
-Under most circumstances, manually downloading this repository should never
-be required.
+# Deprecation note
 
-# Prerequisites
-# Base
-* [Google Protocol Buffers](https://developers.google.com/protocol-buffers)
+This repository used to contain the [protocol
+buffer](https://developers.google.com/protocol-buffers) code that defined both
+the data model and the exposition format of Prometheus metrics.
 
-## Java
-* [Apache Maven](http://maven.apache.org)
-* [Prometheus Maven Repository](https://github.com/prometheus/io.prometheus-maven-repository) checked out into ../io.prometheus-maven-repository
+Starting with v2.0.0, the [Prometheus
+server](https://github.com/prometheus/prometheus) does not ingest the
+protobuf-based exposition format anymore. Currently, all but one of the
+[official instrumentation
+libraries](https://prometheus.io/docs/instrumenting/clientlibs/) do not expose
+the protobuf-based exposition format. The [Go instrumentation
+library](https://github.com/prometheus/client_golang), however, has been built
+around the protobuf-based data model. As a byproduct thereof, it is still able
+to expose the protobuf-based exposition format. The Go instrumentation library
+is the only remaining repository within the [Prometheus GitHub
+org](https://github.com/prometheus) directly using the prometheus/client_model
+repository.
 
-## Go
-*  [Go](http://golang.org)
-*  [goprotobuf](https://code.google.com/p/goprotobuf)
+Therefore, formerly existing support for languages other than Go (namely C++,
+Java, Python, Ruby) has been removed from this repository. If you are a 3rd
+party user of those languages, you can go back to [commit
+14fe0d1](https://github.com/prometheus/client_model/commit/14fe0d1b01d4d5fc031dd4bec1823bd3ebbe8016)
+to keep using the old code, or you can consume
+[`metrics.proto`](https://github.com/prometheus/client_model/blob/master/metrics.proto)
+directly with your own protobuf tooling. Note, however, that changes of
+`metrics.proto` after [commit
+14fe0d1](https://github.com/prometheus/client_model/commit/14fe0d1b01d4d5fc031dd4bec1823bd3ebbe8016)
+are solely informed by requirements of the Go instrumentation library and will
+not take into account any requirements of other languages or stability concerns
+for the protobuf-based exposition format.
 
-## Ruby
-*  [Ruby](https://www.ruby-lang.org)
-*  [bundler](https://rubygems.org/gems/bundler)
-
-# Building
-    $ make
-
-# Getting Started
-  * The Go source code is periodically indexed: [Go Protocol Buffer Model](http://godoc.org/github.com/prometheus/client_model/go).
-  * All of the core developers are accessible via the [Prometheus Developers Mailinglist](https://groups.google.com/forum/?fromgroups#!forum/prometheus-developers).
+Check out the [OpenMetrics project](https://openmetrics.io/) for the future of
+the data model and exposition format used by Prometheus and others.

vendor/github.com/prometheus/client_model/go.mod

@@ -0,0 +1,8 @@
+module github.com/prometheus/client_model
+
+go 1.9
+
+require (
+	github.com/golang/protobuf v1.2.0
+	golang.org/x/sync v0.0.0-20181108010431-42b317875d0f // indirect
+)

vendor/github.com/prometheus/client_model/go/metrics.pb.go

@@ -1,34 +1,26 @@
-// Code generated by protoc-gen-go.
+// Code generated by protoc-gen-go. DO NOT EDIT.
 // source: metrics.proto
-// DO NOT EDIT!
 
-/*
-Package io_prometheus_client is a generated protocol buffer package.
-
-It is generated from these files:
-	metrics.proto
-
-It has these top-level messages:
-	LabelPair
-	Gauge
-	Counter
-	Quantile
-	Summary
-	Untyped
-	Histogram
-	Bucket
-	Metric
-	MetricFamily
-*/
 package io_prometheus_client
 
-import proto "github.com/golang/protobuf/proto"
-import math "math"
+import (
+	fmt "fmt"
+	proto "github.com/golang/protobuf/proto"
+	timestamp "github.com/golang/protobuf/ptypes/timestamp"
+	math "math"
+)
 
 // Reference imports to suppress errors if they are not otherwise used.
 var _ = proto.Marshal
+var _ = fmt.Errorf
 var _ = math.Inf
 
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
+
 type MetricType int32
 
 const (
@@ -46,6 +38,7 @@ var MetricType_name = map[int32]string{
 	3: "UNTYPED",
 	4: "HISTOGRAM",
 }
+
 var MetricType_value = map[string]int32{
 	"COUNTER":   0,
 	"GAUGE":     1,
@@ -59,9 +52,11 @@ func (x MetricType) Enum() *MetricType {
 	*p = x
 	return p
 }
+
 func (x MetricType) String() string {
 	return proto.EnumName(MetricType_name, int32(x))
 }
+
 func (x *MetricType) UnmarshalJSON(data []byte) error {
 	value, err := proto.UnmarshalJSONEnum(MetricType_value, data, "MetricType")
 	if err != nil {
@@ -71,15 +66,42 @@ func (x *MetricType) UnmarshalJSON(data []byte) error {
 	return nil
 }
 
+func (MetricType) EnumDescriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{0}
+}
+
 type LabelPair struct {
-	Name             *string `protobuf:"bytes,1,opt,name=name" json:"name,omitempty"`
-	Value            *string `protobuf:"bytes,2,opt,name=value" json:"value,omitempty"`
-	XXX_unrecognized []byte  `json:"-"`
+	Name                 *string  `protobuf:"bytes,1,opt,name=name" json:"name,omitempty"`
+	Value                *string  `protobuf:"bytes,2,opt,name=value" json:"value,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
 }
 
 func (m *LabelPair) Reset()         { *m = LabelPair{} }
 func (m *LabelPair) String() string { return proto.CompactTextString(m) }
 func (*LabelPair) ProtoMessage()    {}
+func (*LabelPair) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{0}
+}
+
+func (m *LabelPair) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_LabelPair.Unmarshal(m, b)
+}
+func (m *LabelPair) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_LabelPair.Marshal(b, m, deterministic)
+}
+func (m *LabelPair) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_LabelPair.Merge(m, src)
+}
+func (m *LabelPair) XXX_Size() int {
+	return xxx_messageInfo_LabelPair.Size(m)
+}
+func (m *LabelPair) XXX_DiscardUnknown() {
+	xxx_messageInfo_LabelPair.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_LabelPair proto.InternalMessageInfo
 
 func (m *LabelPair) GetName() string {
 	if m != nil && m.Name != nil {
@@ -96,13 +118,36 @@ func (m *LabelPair) GetValue() string {
 }
 
 type Gauge struct {
-	Value            *float64 `protobuf:"fixed64,1,opt,name=value" json:"value,omitempty"`
-	XXX_unrecognized []byte   `json:"-"`
+	Value                *float64 `protobuf:"fixed64,1,opt,name=value" json:"value,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
 }
 
 func (m *Gauge) Reset()         { *m = Gauge{} }
 func (m *Gauge) String() string { return proto.CompactTextString(m) }
 func (*Gauge) ProtoMessage()    {}
+func (*Gauge) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{1}
+}
+
+func (m *Gauge) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Gauge.Unmarshal(m, b)
+}
+func (m *Gauge) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Gauge.Marshal(b, m, deterministic)
+}
+func (m *Gauge) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Gauge.Merge(m, src)
+}
+func (m *Gauge) XXX_Size() int {
+	return xxx_messageInfo_Gauge.Size(m)
+}
+func (m *Gauge) XXX_DiscardUnknown() {
+	xxx_messageInfo_Gauge.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Gauge proto.InternalMessageInfo
 
 func (m *Gauge) GetValue() float64 {
 	if m != nil && m.Value != nil {
@@ -112,13 +157,37 @@ func (m *Gauge) GetValue() float64 {
 }
 
 type Counter struct {
-	Value            *float64 `protobuf:"fixed64,1,opt,name=value" json:"value,omitempty"`
-	XXX_unrecognized []byte   `json:"-"`
+	Value                *float64  `protobuf:"fixed64,1,opt,name=value" json:"value,omitempty"`
+	Exemplar             *Exemplar `protobuf:"bytes,2,opt,name=exemplar" json:"exemplar,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}  `json:"-"`
+	XXX_unrecognized     []byte    `json:"-"`
+	XXX_sizecache        int32     `json:"-"`
 }
 
 func (m *Counter) Reset()         { *m = Counter{} }
 func (m *Counter) String() string { return proto.CompactTextString(m) }
 func (*Counter) ProtoMessage()    {}
+func (*Counter) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{2}
+}
+
+func (m *Counter) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Counter.Unmarshal(m, b)
+}
+func (m *Counter) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Counter.Marshal(b, m, deterministic)
+}
+func (m *Counter) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Counter.Merge(m, src)
+}
+func (m *Counter) XXX_Size() int {
+	return xxx_messageInfo_Counter.Size(m)
+}
+func (m *Counter) XXX_DiscardUnknown() {
+	xxx_messageInfo_Counter.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Counter proto.InternalMessageInfo
 
 func (m *Counter) GetValue() float64 {
 	if m != nil && m.Value != nil {
@@ -127,15 +196,45 @@ func (m *Counter) GetValue() float64 {
 	return 0
 }
 
+func (m *Counter) GetExemplar() *Exemplar {
+	if m != nil {
+		return m.Exemplar
+	}
+	return nil
+}
+
 type Quantile struct {
-	Quantile         *float64 `protobuf:"fixed64,1,opt,name=quantile" json:"quantile,omitempty"`
-	Value            *float64 `protobuf:"fixed64,2,opt,name=value" json:"value,omitempty"`
-	XXX_unrecognized []byte   `json:"-"`
+	Quantile             *float64 `protobuf:"fixed64,1,opt,name=quantile" json:"quantile,omitempty"`
+	Value                *float64 `protobuf:"fixed64,2,opt,name=value" json:"value,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
 }
 
 func (m *Quantile) Reset()         { *m = Quantile{} }
 func (m *Quantile) String() string { return proto.CompactTextString(m) }
 func (*Quantile) ProtoMessage()    {}
+func (*Quantile) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{3}
+}
+
+func (m *Quantile) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Quantile.Unmarshal(m, b)
+}
+func (m *Quantile) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Quantile.Marshal(b, m, deterministic)
+}
+func (m *Quantile) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Quantile.Merge(m, src)
+}
+func (m *Quantile) XXX_Size() int {
+	return xxx_messageInfo_Quantile.Size(m)
+}
+func (m *Quantile) XXX_DiscardUnknown() {
+	xxx_messageInfo_Quantile.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Quantile proto.InternalMessageInfo
 
 func (m *Quantile) GetQuantile() float64 {
 	if m != nil && m.Quantile != nil {
@@ -152,15 +251,38 @@ func (m *Quantile) GetValue() float64 {
 }
 
 type Summary struct {
-	SampleCount      *uint64     `protobuf:"varint,1,opt,name=sample_count" json:"sample_count,omitempty"`
-	SampleSum        *float64    `protobuf:"fixed64,2,opt,name=sample_sum" json:"sample_sum,omitempty"`
-	Quantile         []*Quantile `protobuf:"bytes,3,rep,name=quantile" json:"quantile,omitempty"`
-	XXX_unrecognized []byte      `json:"-"`
+	SampleCount          *uint64     `protobuf:"varint,1,opt,name=sample_count,json=sampleCount" json:"sample_count,omitempty"`
+	SampleSum            *float64    `protobuf:"fixed64,2,opt,name=sample_sum,json=sampleSum" json:"sample_sum,omitempty"`
+	Quantile             []*Quantile `protobuf:"bytes,3,rep,name=quantile" json:"quantile,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}    `json:"-"`
+	XXX_unrecognized     []byte      `json:"-"`
+	XXX_sizecache        int32       `json:"-"`
 }
 
 func (m *Summary) Reset()         { *m = Summary{} }
 func (m *Summary) String() string { return proto.CompactTextString(m) }
 func (*Summary) ProtoMessage()    {}
+func (*Summary) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{4}
+}
+
+func (m *Summary) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Summary.Unmarshal(m, b)
+}
+func (m *Summary) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Summary.Marshal(b, m, deterministic)
+}
+func (m *Summary) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Summary.Merge(m, src)
+}
+func (m *Summary) XXX_Size() int {
+	return xxx_messageInfo_Summary.Size(m)
+}
+func (m *Summary) XXX_DiscardUnknown() {
+	xxx_messageInfo_Summary.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Summary proto.InternalMessageInfo
 
 func (m *Summary) GetSampleCount() uint64 {
 	if m != nil && m.SampleCount != nil {
@@ -184,13 +306,36 @@ func (m *Summary) GetQuantile() []*Quantile {
 }
 
 type Untyped struct {
-	Value            *float64 `protobuf:"fixed64,1,opt,name=value" json:"value,omitempty"`
-	XXX_unrecognized []byte   `json:"-"`
+	Value                *float64 `protobuf:"fixed64,1,opt,name=value" json:"value,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
 }
 
 func (m *Untyped) Reset()         { *m = Untyped{} }
 func (m *Untyped) String() string { return proto.CompactTextString(m) }
 func (*Untyped) ProtoMessage()    {}
+func (*Untyped) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{5}
+}
+
+func (m *Untyped) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Untyped.Unmarshal(m, b)
+}
+func (m *Untyped) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Untyped.Marshal(b, m, deterministic)
+}
+func (m *Untyped) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Untyped.Merge(m, src)
+}
+func (m *Untyped) XXX_Size() int {
+	return xxx_messageInfo_Untyped.Size(m)
+}
+func (m *Untyped) XXX_DiscardUnknown() {
+	xxx_messageInfo_Untyped.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Untyped proto.InternalMessageInfo
 
 func (m *Untyped) GetValue() float64 {
 	if m != nil && m.Value != nil {
@@ -200,15 +345,38 @@ func (m *Untyped) GetValue() float64 {
 }
 
 type Histogram struct {
-	SampleCount      *uint64   `protobuf:"varint,1,opt,name=sample_count" json:"sample_count,omitempty"`
-	SampleSum        *float64  `protobuf:"fixed64,2,opt,name=sample_sum" json:"sample_sum,omitempty"`
-	Bucket           []*Bucket `protobuf:"bytes,3,rep,name=bucket" json:"bucket,omitempty"`
-	XXX_unrecognized []byte    `json:"-"`
+	SampleCount          *uint64   `protobuf:"varint,1,opt,name=sample_count,json=sampleCount" json:"sample_count,omitempty"`
+	SampleSum            *float64  `protobuf:"fixed64,2,opt,name=sample_sum,json=sampleSum" json:"sample_sum,omitempty"`
+	Bucket               []*Bucket `protobuf:"bytes,3,rep,name=bucket" json:"bucket,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}  `json:"-"`
+	XXX_unrecognized     []byte    `json:"-"`
+	XXX_sizecache        int32     `json:"-"`
 }
 
 func (m *Histogram) Reset()         { *m = Histogram{} }
 func (m *Histogram) String() string { return proto.CompactTextString(m) }
 func (*Histogram) ProtoMessage()    {}
+func (*Histogram) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{6}
+}
+
+func (m *Histogram) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Histogram.Unmarshal(m, b)
+}
+func (m *Histogram) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Histogram.Marshal(b, m, deterministic)
+}
+func (m *Histogram) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Histogram.Merge(m, src)
+}
+func (m *Histogram) XXX_Size() int {
+	return xxx_messageInfo_Histogram.Size(m)
+}
+func (m *Histogram) XXX_DiscardUnknown() {
+	xxx_messageInfo_Histogram.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Histogram proto.InternalMessageInfo
 
 func (m *Histogram) GetSampleCount() uint64 {
 	if m != nil && m.SampleCount != nil {
@@ -232,14 +400,38 @@ func (m *Histogram) GetBucket() []*Bucket {
 }
 
 type Bucket struct {
-	CumulativeCount  *uint64  `protobuf:"varint,1,opt,name=cumulative_count" json:"cumulative_count,omitempty"`
-	UpperBound       *float64 `protobuf:"fixed64,2,opt,name=upper_bound" json:"upper_bound,omitempty"`
-	XXX_unrecognized []byte   `json:"-"`
+	CumulativeCount      *uint64   `protobuf:"varint,1,opt,name=cumulative_count,json=cumulativeCount" json:"cumulative_count,omitempty"`
+	UpperBound           *float64  `protobuf:"fixed64,2,opt,name=upper_bound,json=upperBound" json:"upper_bound,omitempty"`
+	Exemplar             *Exemplar `protobuf:"bytes,3,opt,name=exemplar" json:"exemplar,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}  `json:"-"`
+	XXX_unrecognized     []byte    `json:"-"`
+	XXX_sizecache        int32     `json:"-"`
 }
 
 func (m *Bucket) Reset()         { *m = Bucket{} }
 func (m *Bucket) String() string { return proto.CompactTextString(m) }
 func (*Bucket) ProtoMessage()    {}
+func (*Bucket) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{7}
+}
+
+func (m *Bucket) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Bucket.Unmarshal(m, b)
+}
+func (m *Bucket) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Bucket.Marshal(b, m, deterministic)
+}
+func (m *Bucket) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Bucket.Merge(m, src)
+}
+func (m *Bucket) XXX_Size() int {
+	return xxx_messageInfo_Bucket.Size(m)
+}
+func (m *Bucket) XXX_DiscardUnknown() {
+	xxx_messageInfo_Bucket.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Bucket proto.InternalMessageInfo
 
 func (m *Bucket) GetCumulativeCount() uint64 {
 	if m != nil && m.CumulativeCount != nil {
@@ -255,20 +447,105 @@ func (m *Bucket) GetUpperBound() float64 {
 	return 0
 }
 
+func (m *Bucket) GetExemplar() *Exemplar {
+	if m != nil {
+		return m.Exemplar
+	}
+	return nil
+}
+
+type Exemplar struct {
+	Label                []*LabelPair         `protobuf:"bytes,1,rep,name=label" json:"label,omitempty"`
+	Value                *float64             `protobuf:"fixed64,2,opt,name=value" json:"value,omitempty"`
+	Timestamp            *timestamp.Timestamp `protobuf:"bytes,3,opt,name=timestamp" json:"timestamp,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}             `json:"-"`
+	XXX_unrecognized     []byte               `json:"-"`
+	XXX_sizecache        int32                `json:"-"`
+}
+
+func (m *Exemplar) Reset()         { *m = Exemplar{} }
+func (m *Exemplar) String() string { return proto.CompactTextString(m) }
+func (*Exemplar) ProtoMessage()    {}
+func (*Exemplar) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{8}
+}
+
+func (m *Exemplar) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Exemplar.Unmarshal(m, b)
+}
+func (m *Exemplar) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Exemplar.Marshal(b, m, deterministic)
+}
+func (m *Exemplar) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Exemplar.Merge(m, src)
+}
+func (m *Exemplar) XXX_Size() int {
+	return xxx_messageInfo_Exemplar.Size(m)
+}
+func (m *Exemplar) XXX_DiscardUnknown() {
+	xxx_messageInfo_Exemplar.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Exemplar proto.InternalMessageInfo
+
+func (m *Exemplar) GetLabel() []*LabelPair {
+	if m != nil {
+		return m.Label
+	}
+	return nil
+}
+
+func (m *Exemplar) GetValue() float64 {
+	if m != nil && m.Value != nil {
+		return *m.Value
+	}
+	return 0
+}
+
+func (m *Exemplar) GetTimestamp() *timestamp.Timestamp {
+	if m != nil {
+		return m.Timestamp
+	}
+	return nil
+}
+
 type Metric struct {
-	Label            []*LabelPair `protobuf:"bytes,1,rep,name=label" json:"label,omitempty"`
-	Gauge            *Gauge       `protobuf:"bytes,2,opt,name=gauge" json:"gauge,omitempty"`
-	Counter          *Counter     `protobuf:"bytes,3,opt,name=counter" json:"counter,omitempty"`
-	Summary          *Summary     `protobuf:"bytes,4,opt,name=summary" json:"summary,omitempty"`
-	Untyped          *Untyped     `protobuf:"bytes,5,opt,name=untyped" json:"untyped,omitempty"`
-	Histogram        *Histogram   `protobuf:"bytes,7,opt,name=histogram" json:"histogram,omitempty"`
-	TimestampMs      *int64       `protobuf:"varint,6,opt,name=timestamp_ms" json:"timestamp_ms,omitempty"`
-	XXX_unrecognized []byte       `json:"-"`
+	Label                []*LabelPair `protobuf:"bytes,1,rep,name=label" json:"label,omitempty"`
+	Gauge                *Gauge       `protobuf:"bytes,2,opt,name=gauge" json:"gauge,omitempty"`
+	Counter              *Counter     `protobuf:"bytes,3,opt,name=counter" json:"counter,omitempty"`
+	Summary              *Summary     `protobuf:"bytes,4,opt,name=summary" json:"summary,omitempty"`
+	Untyped              *Untyped     `protobuf:"bytes,5,opt,name=untyped" json:"untyped,omitempty"`
+	Histogram            *Histogram   `protobuf:"bytes,7,opt,name=histogram" json:"histogram,omitempty"`
+	TimestampMs          *int64       `protobuf:"varint,6,opt,name=timestamp_ms,json=timestampMs" json:"timestamp_ms,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}     `json:"-"`
+	XXX_unrecognized     []byte       `json:"-"`
+	XXX_sizecache        int32        `json:"-"`
 }
 
 func (m *Metric) Reset()         { *m = Metric{} }
 func (m *Metric) String() string { return proto.CompactTextString(m) }
 func (*Metric) ProtoMessage()    {}
+func (*Metric) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{9}
+}
+
+func (m *Metric) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Metric.Unmarshal(m, b)
+}
+func (m *Metric) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Metric.Marshal(b, m, deterministic)
+}
+func (m *Metric) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Metric.Merge(m, src)
+}
+func (m *Metric) XXX_Size() int {
+	return xxx_messageInfo_Metric.Size(m)
+}
+func (m *Metric) XXX_DiscardUnknown() {
+	xxx_messageInfo_Metric.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Metric proto.InternalMessageInfo
 
 func (m *Metric) GetLabel() []*LabelPair {
 	if m != nil {
@@ -320,16 +597,39 @@ func (m *Metric) GetTimestampMs() int64 {
 }
 
 type MetricFamily struct {
-	Name             *string     `protobuf:"bytes,1,opt,name=name" json:"name,omitempty"`
-	Help             *string     `protobuf:"bytes,2,opt,name=help" json:"help,omitempty"`
-	Type             *MetricType `protobuf:"varint,3,opt,name=type,enum=io.prometheus.client.MetricType" json:"type,omitempty"`
-	Metric           []*Metric   `protobuf:"bytes,4,rep,name=metric" json:"metric,omitempty"`
-	XXX_unrecognized []byte      `json:"-"`
+	Name                 *string     `protobuf:"bytes,1,opt,name=name" json:"name,omitempty"`
+	Help                 *string     `protobuf:"bytes,2,opt,name=help" json:"help,omitempty"`
+	Type                 *MetricType `protobuf:"varint,3,opt,name=type,enum=io.prometheus.client.MetricType" json:"type,omitempty"`
+	Metric               []*Metric   `protobuf:"bytes,4,rep,name=metric" json:"metric,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}    `json:"-"`
+	XXX_unrecognized     []byte      `json:"-"`
+	XXX_sizecache        int32       `json:"-"`
 }
 
 func (m *MetricFamily) Reset()         { *m = MetricFamily{} }
 func (m *MetricFamily) String() string { return proto.CompactTextString(m) }
 func (*MetricFamily) ProtoMessage()    {}
+func (*MetricFamily) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{10}
+}
+
+func (m *MetricFamily) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_MetricFamily.Unmarshal(m, b)
+}
+func (m *MetricFamily) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_MetricFamily.Marshal(b, m, deterministic)
+}
+func (m *MetricFamily) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_MetricFamily.Merge(m, src)
+}
+func (m *MetricFamily) XXX_Size() int {
+	return xxx_messageInfo_MetricFamily.Size(m)
+}
+func (m *MetricFamily) XXX_DiscardUnknown() {
+	xxx_messageInfo_MetricFamily.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_MetricFamily proto.InternalMessageInfo
 
 func (m *MetricFamily) GetName() string {
 	if m != nil && m.Name != nil {
@@ -361,4 +661,63 @@ func (m *MetricFamily) GetMetric() []*Metric {
 
 func init() {
 	proto.RegisterEnum("io.prometheus.client.MetricType", MetricType_name, MetricType_value)
+	proto.RegisterType((*LabelPair)(nil), "io.prometheus.client.LabelPair")
+	proto.RegisterType((*Gauge)(nil), "io.prometheus.client.Gauge")
+	proto.RegisterType((*Counter)(nil), "io.prometheus.client.Counter")
+	proto.RegisterType((*Quantile)(nil), "io.prometheus.client.Quantile")
+	proto.RegisterType((*Summary)(nil), "io.prometheus.client.Summary")
+	proto.RegisterType((*Untyped)(nil), "io.prometheus.client.Untyped")
+	proto.RegisterType((*Histogram)(nil), "io.prometheus.client.Histogram")
+	proto.RegisterType((*Bucket)(nil), "io.prometheus.client.Bucket")
+	proto.RegisterType((*Exemplar)(nil), "io.prometheus.client.Exemplar")
+	proto.RegisterType((*Metric)(nil), "io.prometheus.client.Metric")
+	proto.RegisterType((*MetricFamily)(nil), "io.prometheus.client.MetricFamily")
+}
+
+func init() { proto.RegisterFile("metrics.proto", fileDescriptor_6039342a2ba47b72) }
+
+var fileDescriptor_6039342a2ba47b72 = []byte{
+	// 665 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xac, 0x54, 0xcd, 0x6e, 0xd3, 0x4c,
+	0x14, 0xfd, 0xdc, 0x38, 0x3f, 0xbe, 0x69, 0x3f, 0xa2, 0x51, 0x17, 0x56, 0xa1, 0x24, 0x78, 0x55,
+	0x58, 0x38, 0xa2, 0x6a, 0x05, 0x2a, 0xb0, 0x68, 0x4b, 0x48, 0x91, 0x48, 0x5b, 0x26, 0xc9, 0xa2,
+	0xb0, 0x88, 0x1c, 0x77, 0x70, 0x2c, 0x3c, 0xb1, 0xb1, 0x67, 0x2a, 0xb2, 0x66, 0xc1, 0x16, 0x5e,
+	0x81, 0x17, 0x05, 0xcd, 0x8f, 0x6d, 0x2a, 0xb9, 0x95, 0x40, 0xec, 0x66, 0xee, 0x3d, 0xe7, 0xfa,
+	0xcc, 0xf8, 0x9c, 0x81, 0x0d, 0x4a, 0x58, 0x1a, 0xfa, 0x99, 0x9b, 0xa4, 0x31, 0x8b, 0xd1, 0x66,
+	0x18, 0x8b, 0x15, 0x25, 0x6c, 0x41, 0x78, 0xe6, 0xfa, 0x51, 0x48, 0x96, 0x6c, 0xab, 0x1b, 0xc4,
+	0x71, 0x10, 0x91, 0xbe, 0xc4, 0xcc, 0xf9, 0x87, 0x3e, 0x0b, 0x29, 0xc9, 0x98, 0x47, 0x13, 0x45,
+	0x73, 0xf6, 0xc1, 0x7a, 0xe3, 0xcd, 0x49, 0x74, 0xee, 0x85, 0x29, 0x42, 0x60, 0x2e, 0x3d, 0x4a,
+	0x6c, 0xa3, 0x67, 0xec, 0x58, 0x58, 0xae, 0xd1, 0x26, 0xd4, 0xaf, 0xbc, 0x88, 0x13, 0x7b, 0x4d,
+	0x16, 0xd5, 0xc6, 0xd9, 0x86, 0xfa, 0xd0, 0xe3, 0xc1, 0x6f, 0x6d, 0xc1, 0x31, 0xf2, 0xf6, 0x7b,
+	0x68, 0x1e, 0xc7, 0x7c, 0xc9, 0x48, 0x5a, 0x0d, 0x40, 0x07, 0xd0, 0x22, 0x9f, 0x09, 0x4d, 0x22,
+	0x2f, 0x95, 0x83, 0xdb, 0xbb, 0xf7, 0xdd, 0xaa, 0x03, 0xb8, 0x03, 0x8d, 0xc2, 0x05, 0xde, 0x79,
+	0x0e, 0xad, 0xb7, 0xdc, 0x5b, 0xb2, 0x30, 0x22, 0x68, 0x0b, 0x5a, 0x9f, 0xf4, 0x5a, 0x7f, 0xa0,
+	0xd8, 0x5f, 0x57, 0x5e, 0x48, 0xfb, 0x6a, 0x40, 0x73, 0xcc, 0x29, 0xf5, 0xd2, 0x15, 0x7a, 0x00,
+	0xeb, 0x99, 0x47, 0x93, 0x88, 0xcc, 0x7c, 0xa1, 0x56, 0x4e, 0x30, 0x71, 0x5b, 0xd5, 0xe4, 0x01,
+	0xd0, 0x36, 0x80, 0x86, 0x64, 0x9c, 0xea, 0x49, 0x96, 0xaa, 0x8c, 0x39, 0x15, 0xe7, 0x28, 0xbe,
+	0x5f, 0xeb, 0xd5, 0x6e, 0x3e, 0x47, 0xae, 0xb8, 0xd4, 0xe7, 0x74, 0xa1, 0x39, 0x5d, 0xb2, 0x55,
+	0x42, 0x2e, 0x6f, 0xb8, 0xc5, 0x2f, 0x06, 0x58, 0x27, 0x61, 0xc6, 0xe2, 0x20, 0xf5, 0xe8, 0x3f,
+	0x10, 0xbb, 0x07, 0x8d, 0x39, 0xf7, 0x3f, 0x12, 0xa6, 0xa5, 0xde, 0xab, 0x96, 0x7a, 0x24, 0x31,
+	0x58, 0x63, 0x9d, 0x6f, 0x06, 0x34, 0x54, 0x09, 0x3d, 0x84, 0x8e, 0xcf, 0x29, 0x8f, 0x3c, 0x16,
+	0x5e, 0x5d, 0x97, 0x71, 0xa7, 0xac, 0x2b, 0x29, 0x5d, 0x68, 0xf3, 0x24, 0x21, 0xe9, 0x6c, 0x1e,
+	0xf3, 0xe5, 0xa5, 0xd6, 0x02, 0xb2, 0x74, 0x24, 0x2a, 0xd7, 0x1c, 0x50, 0xfb, 0x43, 0x07, 0x7c,
+	0x37, 0xa0, 0x95, 0x97, 0xd1, 0x3e, 0xd4, 0x23, 0xe1, 0x60, 0xdb, 0x90, 0x87, 0xea, 0x56, 0x4f,
+	0x29, 0x4c, 0x8e, 0x15, 0xba, 0xda, 0x1d, 0xe8, 0x29, 0x58, 0x45, 0x42, 0xb4, 0xac, 0x2d, 0x57,
+	0x65, 0xc8, 0xcd, 0x33, 0xe4, 0x4e, 0x72, 0x04, 0x2e, 0xc1, 0xce, 0xcf, 0x35, 0x68, 0x8c, 0x64,
+	0x22, 0xff, 0x56, 0xd1, 0x63, 0xa8, 0x07, 0x22, 0x53, 0x3a, 0x10, 0x77, 0xab, 0x69, 0x32, 0x76,
+	0x58, 0x21, 0xd1, 0x13, 0x68, 0xfa, 0x2a, 0x67, 0x5a, 0xec, 0x76, 0x35, 0x49, 0x87, 0x11, 0xe7,
+	0x68, 0x41, 0xcc, 0x54, 0x08, 0x6c, 0xf3, 0x36, 0xa2, 0x4e, 0x0a, 0xce, 0xd1, 0x82, 0xc8, 0x95,
+	0x69, 0xed, 0xfa, 0x6d, 0x44, 0xed, 0x6c, 0x9c, 0xa3, 0xd1, 0x0b, 0xb0, 0x16, 0xb9, 0x97, 0xed,
+	0xa6, 0xa4, 0xde, 0x70, 0x31, 0x85, 0xe5, 0x71, 0xc9, 0x10, 0xee, 0x2f, 0xee, 0x7a, 0x46, 0x33,
+	0xbb, 0xd1, 0x33, 0x76, 0x6a, 0xb8, 0x5d, 0xd4, 0x46, 0x99, 0xf3, 0xc3, 0x80, 0x75, 0xf5, 0x07,
+	0x5e, 0x79, 0x34, 0x8c, 0x56, 0x95, 0xcf, 0x19, 0x02, 0x73, 0x41, 0xa2, 0x44, 0xbf, 0x66, 0x72,
+	0x8d, 0xf6, 0xc0, 0x14, 0x1a, 0xe5, 0x15, 0xfe, 0xbf, 0xdb, 0xab, 0x56, 0xa5, 0x26, 0x4f, 0x56,
+	0x09, 0xc1, 0x12, 0x2d, 0xd2, 0xa4, 0x5e, 0x60, 0xdb, 0xbc, 0x2d, 0x4d, 0x8a, 0x87, 0x35, 0xf6,
+	0xd1, 0x08, 0xa0, 0x9c, 0x84, 0xda, 0xd0, 0x3c, 0x3e, 0x9b, 0x9e, 0x4e, 0x06, 0xb8, 0xf3, 0x1f,
+	0xb2, 0xa0, 0x3e, 0x3c, 0x9c, 0x0e, 0x07, 0x1d, 0x43, 0xd4, 0xc7, 0xd3, 0xd1, 0xe8, 0x10, 0x5f,
+	0x74, 0xd6, 0xc4, 0x66, 0x7a, 0x3a, 0xb9, 0x38, 0x1f, 0xbc, 0xec, 0xd4, 0xd0, 0x06, 0x58, 0x27,
+	0xaf, 0xc7, 0x93, 0xb3, 0x21, 0x3e, 0x1c, 0x75, 0xcc, 0x23, 0x0c, 0x95, 0xef, 0xfe, 0xbb, 0x83,
+	0x20, 0x64, 0x0b, 0x3e, 0x77, 0xfd, 0x98, 0xf6, 0xcb, 0x6e, 0x5f, 0x75, 0x67, 0x34, 0xbe, 0x24,
+	0x51, 0x3f, 0x88, 0x9f, 0x85, 0xf1, 0xac, 0xec, 0xce, 0x54, 0xf7, 0x57, 0x00, 0x00, 0x00, 0xff,
+	0xff, 0xd0, 0x84, 0x91, 0x73, 0x59, 0x06, 0x00, 0x00,
 }

vendor/github.com/prometheus/common/README.md

@@ -6,7 +6,11 @@ components and libraries.
 
 * **config**: Common configuration structures
 * **expfmt**: Decoding and encoding for the exposition format
-* **log**: A logging wrapper around [logrus](https://github.com/sirupsen/logrus)
 * **model**: Shared data structures
+* **promlog**: A logging wrapper around [go-kit/log](https://github.com/go-kit/kit/tree/master/log)
 * **route**: A routing wrapper around [httprouter](https://github.com/julienschmidt/httprouter) using `context.Context`
+* **server**: Common servers
 * **version**: Version information and metrics
+
+## Deprecated
+* **log**: A logging wrapper around [logrus](https://github.com/sirupsen/logrus)

vendor/github.com/prometheus/common/expfmt/encode.go

@@ -30,17 +30,38 @@ type Encoder interface {
 	Encode(*dto.MetricFamily) error
 }
 
-type encoder func(*dto.MetricFamily) error
-
-func (e encoder) Encode(v *dto.MetricFamily) error {
-	return e(v)
+// Closer is implemented by Encoders that need to be closed to finalize
+// encoding. (For example, OpenMetrics needs a final `# EOF` line.)
+//
+// Note that all Encoder implementations returned from this package implement
+// Closer, too, even if the Close call is a no-op. This happens in preparation
+// for adding a Close method to the Encoder interface directly in a (mildly
+// breaking) release in the future.
+type Closer interface {
+	Close() error
 }
 
-// Negotiate returns the Content-Type based on the given Accept header.
-// If no appropriate accepted type is found, FmtText is returned.
+type encoderCloser struct {
+	encode func(*dto.MetricFamily) error
+	close  func() error
+}
+
+func (ec encoderCloser) Encode(v *dto.MetricFamily) error {
+	return ec.encode(v)
+}
+
+func (ec encoderCloser) Close() error {
+	return ec.close()
+}
+
+// Negotiate returns the Content-Type based on the given Accept header. If no
+// appropriate accepted type is found, FmtText is returned (which is the
+// Prometheus text format). This function will never negotiate FmtOpenMetrics,
+// as the support is still experimental. To include the option to negotiate
+// FmtOpenMetrics, use NegotiateOpenMetrics.
 func Negotiate(h http.Header) Format {
 	for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
-		// Check for protocol buffer
+		ver := ac.Params["version"]
 		if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
 			switch ac.Params["encoding"] {
 			case "delimited":
@@ -51,8 +72,6 @@ func Negotiate(h http.Header) Format {
 				return FmtProtoCompact
 			}
 		}
-		// Check for text format.
-		ver := ac.Params["version"]
 		if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
 			return FmtText
 		}
@@ -60,29 +79,84 @@ func Negotiate(h http.Header) Format {
 	return FmtText
 }
 
-// NewEncoder returns a new encoder based on content type negotiation.
+// NegotiateIncludingOpenMetrics works like Negotiate but includes
+// FmtOpenMetrics as an option for the result. Note that this function is
+// temporary and will disappear once FmtOpenMetrics is fully supported and as
+// such may be negotiated by the normal Negotiate function.
+func NegotiateIncludingOpenMetrics(h http.Header) Format {
+	for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
+		ver := ac.Params["version"]
+		if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
+			switch ac.Params["encoding"] {
+			case "delimited":
+				return FmtProtoDelim
+			case "text":
+				return FmtProtoText
+			case "compact-text":
+				return FmtProtoCompact
+			}
+		}
+		if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
+			return FmtText
+		}
+		if ac.Type+"/"+ac.SubType == OpenMetricsType && (ver == OpenMetricsVersion || ver == "") {
+			return FmtOpenMetrics
+		}
+	}
+	return FmtText
+}
+
+// NewEncoder returns a new encoder based on content type negotiation. All
+// Encoder implementations returned by NewEncoder also implement Closer, and
+// callers should always call the Close method. It is currently only required
+// for FmtOpenMetrics, but a future (breaking) release will add the Close method
+// to the Encoder interface directly. The current version of the Encoder
+// interface is kept for backwards compatibility.
 func NewEncoder(w io.Writer, format Format) Encoder {
 	switch format {
 	case FmtProtoDelim:
-		return encoder(func(v *dto.MetricFamily) error {
-			_, err := pbutil.WriteDelimited(w, v)
-			return err
-		})
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := pbutil.WriteDelimited(w, v)
+				return err
+			},
+			close: func() error { return nil },
+		}
 	case FmtProtoCompact:
-		return encoder(func(v *dto.MetricFamily) error {
-			_, err := fmt.Fprintln(w, v.String())
-			return err
-		})
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := fmt.Fprintln(w, v.String())
+				return err
+			},
+			close: func() error { return nil },
+		}
 	case FmtProtoText:
-		return encoder(func(v *dto.MetricFamily) error {
-			_, err := fmt.Fprintln(w, proto.MarshalTextString(v))
-			return err
-		})
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := fmt.Fprintln(w, proto.MarshalTextString(v))
+				return err
+			},
+			close: func() error { return nil },
+		}
 	case FmtText:
-		return encoder(func(v *dto.MetricFamily) error {
-			_, err := MetricFamilyToText(w, v)
-			return err
-		})
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := MetricFamilyToText(w, v)
+				return err
+			},
+			close: func() error { return nil },
+		}
+	case FmtOpenMetrics:
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := MetricFamilyToOpenMetrics(w, v)
+				return err
+			},
+			close: func() error {
+				_, err := FinalizeOpenMetrics(w)
+				return err
+			},
+		}
 	}
-	panic("expfmt.NewEncoder: unknown format")
+	panic(fmt.Errorf("expfmt.NewEncoder: unknown format %q", format))
 }

vendor/github.com/prometheus/common/expfmt/expfmt.go

@@ -19,10 +19,12 @@ type Format string
 
 // Constants to assemble the Content-Type values for the different wire protocols.
 const (
-	TextVersion   = "0.0.4"
-	ProtoType     = `application/vnd.google.protobuf`
-	ProtoProtocol = `io.prometheus.client.MetricFamily`
-	ProtoFmt      = ProtoType + "; proto=" + ProtoProtocol + ";"
+	TextVersion        = "0.0.4"
+	ProtoType          = `application/vnd.google.protobuf`
+	ProtoProtocol      = `io.prometheus.client.MetricFamily`
+	ProtoFmt           = ProtoType + "; proto=" + ProtoProtocol + ";"
+	OpenMetricsType    = `application/openmetrics-text`
+	OpenMetricsVersion = "0.0.1"
 
 	// The Content-Type values for the different wire protocols.
 	FmtUnknown      Format = `<unknown>`
@@ -30,6 +32,7 @@ const (
 	FmtProtoDelim   Format = ProtoFmt + ` encoding=delimited`
 	FmtProtoText    Format = ProtoFmt + ` encoding=text`
 	FmtProtoCompact Format = ProtoFmt + ` encoding=compact-text`
+	FmtOpenMetrics  Format = OpenMetricsType + `; version=` + OpenMetricsVersion + `; charset=utf-8`
 )
 
 const (

vendor/github.com/prometheus/common/expfmt/openmetrics_create.go

@@ -0,0 +1,527 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package expfmt
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"math"
+	"strconv"
+	"strings"
+
+	"github.com/golang/protobuf/ptypes"
+	"github.com/prometheus/common/model"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
+// MetricFamilyToOpenMetrics converts a MetricFamily proto message into the
+// OpenMetrics text format and writes the resulting lines to 'out'. It returns
+// the number of bytes written and any error encountered. The output will have
+// the same order as the input, no further sorting is performed. Furthermore,
+// this function assumes the input is already sanitized and does not perform any
+// sanity checks. If the input contains duplicate metrics or invalid metric or
+// label names, the conversion will result in invalid text format output.
+//
+// This function fulfills the type 'expfmt.encoder'.
+//
+// Note that OpenMetrics requires a final `# EOF` line. Since this function acts
+// on individual metric families, it is the responsibility of the caller to
+// append this line to 'out' once all metric families have been written.
+// Conveniently, this can be done by calling FinalizeOpenMetrics.
+//
+// The output should be fully OpenMetrics compliant. However, there are a few
+// missing features and peculiarities to avoid complications when switching from
+// Prometheus to OpenMetrics or vice versa:
+//
+// - Counters are expected to have the `_total` suffix in their metric name. In
+//   the output, the suffix will be truncated from the `# TYPE` and `# HELP`
+//   line. A counter with a missing `_total` suffix is not an error. However,
+//   its type will be set to `unknown` in that case to avoid invalid OpenMetrics
+//   output.
+//
+// - No support for the following (optional) features: `# UNIT` line, `_created`
+//   line, info type, stateset type, gaugehistogram type.
+//
+// - The size of exemplar labels is not checked (i.e. it's possible to create
+//   exemplars that are larger than allowed by the OpenMetrics specification).
+//
+// - The value of Counters is not checked. (OpenMetrics doesn't allow counters
+//   with a `NaN` value.)
+func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily) (written int, err error) {
+	name := in.GetName()
+	if name == "" {
+		return 0, fmt.Errorf("MetricFamily has no name: %s", in)
+	}
+
+	// Try the interface upgrade. If it doesn't work, we'll use a
+	// bufio.Writer from the sync.Pool.
+	w, ok := out.(enhancedWriter)
+	if !ok {
+		b := bufPool.Get().(*bufio.Writer)
+		b.Reset(out)
+		w = b
+		defer func() {
+			bErr := b.Flush()
+			if err == nil {
+				err = bErr
+			}
+			bufPool.Put(b)
+		}()
+	}
+
+	var (
+		n          int
+		metricType = in.GetType()
+		shortName  = name
+	)
+	if metricType == dto.MetricType_COUNTER && strings.HasSuffix(shortName, "_total") {
+		shortName = name[:len(name)-6]
+	}
+
+	// Comments, first HELP, then TYPE.
+	if in.Help != nil {
+		n, err = w.WriteString("# HELP ")
+		written += n
+		if err != nil {
+			return
+		}
+		n, err = w.WriteString(shortName)
+		written += n
+		if err != nil {
+			return
+		}
+		err = w.WriteByte(' ')
+		written++
+		if err != nil {
+			return
+		}
+		n, err = writeEscapedString(w, *in.Help, true)
+		written += n
+		if err != nil {
+			return
+		}
+		err = w.WriteByte('\n')
+		written++
+		if err != nil {
+			return
+		}
+	}
+	n, err = w.WriteString("# TYPE ")
+	written += n
+	if err != nil {
+		return
+	}
+	n, err = w.WriteString(shortName)
+	written += n
+	if err != nil {
+		return
+	}
+	switch metricType {
+	case dto.MetricType_COUNTER:
+		if strings.HasSuffix(name, "_total") {
+			n, err = w.WriteString(" counter\n")
+		} else {
+			n, err = w.WriteString(" unknown\n")
+		}
+	case dto.MetricType_GAUGE:
+		n, err = w.WriteString(" gauge\n")
+	case dto.MetricType_SUMMARY:
+		n, err = w.WriteString(" summary\n")
+	case dto.MetricType_UNTYPED:
+		n, err = w.WriteString(" unknown\n")
+	case dto.MetricType_HISTOGRAM:
+		n, err = w.WriteString(" histogram\n")
+	default:
+		return written, fmt.Errorf("unknown metric type %s", metricType.String())
+	}
+	written += n
+	if err != nil {
+		return
+	}
+
+	// Finally the samples, one line for each.
+	for _, metric := range in.Metric {
+		switch metricType {
+		case dto.MetricType_COUNTER:
+			if metric.Counter == nil {
+				return written, fmt.Errorf(
+					"expected counter in metric %s %s", name, metric,
+				)
+			}
+			// Note that we have ensured above that either the name
+			// ends on `_total` or that the rendered type is
+			// `unknown`. Therefore, no `_total` must be added here.
+			n, err = writeOpenMetricsSample(
+				w, name, "", metric, "", 0,
+				metric.Counter.GetValue(), 0, false,
+				metric.Counter.Exemplar,
+			)
+		case dto.MetricType_GAUGE:
+			if metric.Gauge == nil {
+				return written, fmt.Errorf(
+					"expected gauge in metric %s %s", name, metric,
+				)
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "", metric, "", 0,
+				metric.Gauge.GetValue(), 0, false,
+				nil,
+			)
+		case dto.MetricType_UNTYPED:
+			if metric.Untyped == nil {
+				return written, fmt.Errorf(
+					"expected untyped in metric %s %s", name, metric,
+				)
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "", metric, "", 0,
+				metric.Untyped.GetValue(), 0, false,
+				nil,
+			)
+		case dto.MetricType_SUMMARY:
+			if metric.Summary == nil {
+				return written, fmt.Errorf(
+					"expected summary in metric %s %s", name, metric,
+				)
+			}
+			for _, q := range metric.Summary.Quantile {
+				n, err = writeOpenMetricsSample(
+					w, name, "", metric,
+					model.QuantileLabel, q.GetQuantile(),
+					q.GetValue(), 0, false,
+					nil,
+				)
+				written += n
+				if err != nil {
+					return
+				}
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "_sum", metric, "", 0,
+				metric.Summary.GetSampleSum(), 0, false,
+				nil,
+			)
+			written += n
+			if err != nil {
+				return
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "_count", metric, "", 0,
+				0, metric.Summary.GetSampleCount(), true,
+				nil,
+			)
+		case dto.MetricType_HISTOGRAM:
+			if metric.Histogram == nil {
+				return written, fmt.Errorf(
+					"expected histogram in metric %s %s", name, metric,
+				)
+			}
+			infSeen := false
+			for _, b := range metric.Histogram.Bucket {
+				n, err = writeOpenMetricsSample(
+					w, name, "_bucket", metric,
+					model.BucketLabel, b.GetUpperBound(),
+					0, b.GetCumulativeCount(), true,
+					b.Exemplar,
+				)
+				written += n
+				if err != nil {
+					return
+				}
+				if math.IsInf(b.GetUpperBound(), +1) {
+					infSeen = true
+				}
+			}
+			if !infSeen {
+				n, err = writeOpenMetricsSample(
+					w, name, "_bucket", metric,
+					model.BucketLabel, math.Inf(+1),
+					0, metric.Histogram.GetSampleCount(), true,
+					nil,
+				)
+				written += n
+				if err != nil {
+					return
+				}
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "_sum", metric, "", 0,
+				metric.Histogram.GetSampleSum(), 0, false,
+				nil,
+			)
+			written += n
+			if err != nil {
+				return
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "_count", metric, "", 0,
+				0, metric.Histogram.GetSampleCount(), true,
+				nil,
+			)
+		default:
+			return written, fmt.Errorf(
+				"unexpected type in metric %s %s", name, metric,
+			)
+		}
+		written += n
+		if err != nil {
+			return
+		}
+	}
+	return
+}
+
+// FinalizeOpenMetrics writes the final `# EOF\n` line required by OpenMetrics.
+func FinalizeOpenMetrics(w io.Writer) (written int, err error) {
+	return w.Write([]byte("# EOF\n"))
+}
+
+// writeOpenMetricsSample writes a single sample in OpenMetrics text format to
+// w, given the metric name, the metric proto message itself, optionally an
+// additional label name with a float64 value (use empty string as label name if
+// not required), the value (optionally as float64 or uint64, determined by
+// useIntValue), and optionally an exemplar (use nil if not required). The
+// function returns the number of bytes written and any error encountered.
+func writeOpenMetricsSample(
+	w enhancedWriter,
+	name, suffix string,
+	metric *dto.Metric,
+	additionalLabelName string, additionalLabelValue float64,
+	floatValue float64, intValue uint64, useIntValue bool,
+	exemplar *dto.Exemplar,
+) (int, error) {
+	var written int
+	n, err := w.WriteString(name)
+	written += n
+	if err != nil {
+		return written, err
+	}
+	if suffix != "" {
+		n, err = w.WriteString(suffix)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+	n, err = writeOpenMetricsLabelPairs(
+		w, metric.Label, additionalLabelName, additionalLabelValue,
+	)
+	written += n
+	if err != nil {
+		return written, err
+	}
+	err = w.WriteByte(' ')
+	written++
+	if err != nil {
+		return written, err
+	}
+	if useIntValue {
+		n, err = writeUint(w, intValue)
+	} else {
+		n, err = writeOpenMetricsFloat(w, floatValue)
+	}
+	written += n
+	if err != nil {
+		return written, err
+	}
+	if metric.TimestampMs != nil {
+		err = w.WriteByte(' ')
+		written++
+		if err != nil {
+			return written, err
+		}
+		// TODO(beorn7): Format this directly without converting to a float first.
+		n, err = writeOpenMetricsFloat(w, float64(*metric.TimestampMs)/1000)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+	if exemplar != nil {
+		n, err = writeExemplar(w, exemplar)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+	err = w.WriteByte('\n')
+	written++
+	if err != nil {
+		return written, err
+	}
+	return written, nil
+}
+
+// writeOpenMetricsLabelPairs works like writeOpenMetrics but formats the float
+// in OpenMetrics style.
+func writeOpenMetricsLabelPairs(
+	w enhancedWriter,
+	in []*dto.LabelPair,
+	additionalLabelName string, additionalLabelValue float64,
+) (int, error) {
+	if len(in) == 0 && additionalLabelName == "" {
+		return 0, nil
+	}
+	var (
+		written   int
+		separator byte = '{'
+	)
+	for _, lp := range in {
+		err := w.WriteByte(separator)
+		written++
+		if err != nil {
+			return written, err
+		}
+		n, err := w.WriteString(lp.GetName())
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = w.WriteString(`="`)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = writeEscapedString(w, lp.GetValue(), true)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		err = w.WriteByte('"')
+		written++
+		if err != nil {
+			return written, err
+		}
+		separator = ','
+	}
+	if additionalLabelName != "" {
+		err := w.WriteByte(separator)
+		written++
+		if err != nil {
+			return written, err
+		}
+		n, err := w.WriteString(additionalLabelName)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = w.WriteString(`="`)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = writeOpenMetricsFloat(w, additionalLabelValue)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		err = w.WriteByte('"')
+		written++
+		if err != nil {
+			return written, err
+		}
+	}
+	err := w.WriteByte('}')
+	written++
+	if err != nil {
+		return written, err
+	}
+	return written, nil
+}
+
+// writeExemplar writes the provided exemplar in OpenMetrics format to w. The
+// function returns the number of bytes written and any error encountered.
+func writeExemplar(w enhancedWriter, e *dto.Exemplar) (int, error) {
+	written := 0
+	n, err := w.WriteString(" # ")
+	written += n
+	if err != nil {
+		return written, err
+	}
+	n, err = writeOpenMetricsLabelPairs(w, e.Label, "", 0)
+	written += n
+	if err != nil {
+		return written, err
+	}
+	err = w.WriteByte(' ')
+	written++
+	if err != nil {
+		return written, err
+	}
+	n, err = writeOpenMetricsFloat(w, e.GetValue())
+	written += n
+	if err != nil {
+		return written, err
+	}
+	if e.Timestamp != nil {
+		err = w.WriteByte(' ')
+		written++
+		if err != nil {
+			return written, err
+		}
+		ts, err := ptypes.Timestamp((*e).Timestamp)
+		if err != nil {
+			return written, err
+		}
+		// TODO(beorn7): Format this directly from components of ts to
+		// avoid overflow/underflow and precision issues of the float
+		// conversion.
+		n, err = writeOpenMetricsFloat(w, float64(ts.UnixNano())/1e9)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+	return written, nil
+}
+
+// writeOpenMetricsFloat works like writeFloat but appends ".0" if the resulting
+// number would otherwise contain neither a "." nor an "e".
+func writeOpenMetricsFloat(w enhancedWriter, f float64) (int, error) {
+	switch {
+	case f == 1:
+		return w.WriteString("1.0")
+	case f == 0:
+		return w.WriteString("0.0")
+	case f == -1:
+		return w.WriteString("-1.0")
+	case math.IsNaN(f):
+		return w.WriteString("NaN")
+	case math.IsInf(f, +1):
+		return w.WriteString("+Inf")
+	case math.IsInf(f, -1):
+		return w.WriteString("-Inf")
+	default:
+		bp := numBufPool.Get().(*[]byte)
+		*bp = strconv.AppendFloat((*bp)[:0], f, 'g', -1, 64)
+		if !bytes.ContainsAny(*bp, "e.") {
+			*bp = append(*bp, '.', '0')
+		}
+		written, err := w.Write(*bp)
+		numBufPool.Put(bp)
+		return written, err
+	}
+}
+
+// writeUint is like writeInt just for uint64.
+func writeUint(w enhancedWriter, u uint64) (int, error) {
+	bp := numBufPool.Get().(*[]byte)
+	*bp = strconv.AppendUint((*bp)[:0], u, 10)
+	written, err := w.Write(*bp)
+	numBufPool.Put(bp)
+	return written, err
+}

vendor/github.com/prometheus/common/expfmt/text_create.go

@@ -14,13 +14,45 @@
 package expfmt
 
 import (
+	"bufio"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"math"
+	"strconv"
 	"strings"
+	"sync"
+
+	"github.com/prometheus/common/model"
 
 	dto "github.com/prometheus/client_model/go"
-	"github.com/prometheus/common/model"
+)
+
+// enhancedWriter has all the enhanced write functions needed here. bufio.Writer
+// implements it.
+type enhancedWriter interface {
+	io.Writer
+	WriteRune(r rune) (n int, err error)
+	WriteString(s string) (n int, err error)
+	WriteByte(c byte) error
+}
+
+const (
+	initialNumBufSize = 24
+)
+
+var (
+	bufPool = sync.Pool{
+		New: func() interface{} {
+			return bufio.NewWriter(ioutil.Discard)
+		},
+	}
+	numBufPool = sync.Pool{
+		New: func() interface{} {
+			b := make([]byte, 0, initialNumBufSize)
+			return &b
+		},
+	}
 )
 
 // MetricFamilyToText converts a MetricFamily proto message into text format and
@@ -32,37 +64,90 @@ import (
 // will result in invalid text format output.
 //
 // This method fulfills the type 'prometheus.encoder'.
-func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
-	var written int
-
+func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err error) {
 	// Fail-fast checks.
 	if len(in.Metric) == 0 {
-		return written, fmt.Errorf("MetricFamily has no metrics: %s", in)
+		return 0, fmt.Errorf("MetricFamily has no metrics: %s", in)
 	}
 	name := in.GetName()
 	if name == "" {
-		return written, fmt.Errorf("MetricFamily has no name: %s", in)
+		return 0, fmt.Errorf("MetricFamily has no name: %s", in)
 	}
 
+	// Try the interface upgrade. If it doesn't work, we'll use a
+	// bufio.Writer from the sync.Pool.
+	w, ok := out.(enhancedWriter)
+	if !ok {
+		b := bufPool.Get().(*bufio.Writer)
+		b.Reset(out)
+		w = b
+		defer func() {
+			bErr := b.Flush()
+			if err == nil {
+				err = bErr
+			}
+			bufPool.Put(b)
+		}()
+	}
+
+	var n int
+
 	// Comments, first HELP, then TYPE.
 	if in.Help != nil {
-		n, err := fmt.Fprintf(
-			out, "# HELP %s %s\n",
-			name, escapeString(*in.Help, false),
-		)
+		n, err = w.WriteString("# HELP ")
 		written += n
 		if err != nil {
-			return written, err
+			return
+		}
+		n, err = w.WriteString(name)
+		written += n
+		if err != nil {
+			return
+		}
+		err = w.WriteByte(' ')
+		written++
+		if err != nil {
+			return
+		}
+		n, err = writeEscapedString(w, *in.Help, false)
+		written += n
+		if err != nil {
+			return
+		}
+		err = w.WriteByte('\n')
+		written++
+		if err != nil {
+			return
 		}
 	}
-	metricType := in.GetType()
-	n, err := fmt.Fprintf(
-		out, "# TYPE %s %s\n",
-		name, strings.ToLower(metricType.String()),
-	)
+	n, err = w.WriteString("# TYPE ")
 	written += n
 	if err != nil {
-		return written, err
+		return
+	}
+	n, err = w.WriteString(name)
+	written += n
+	if err != nil {
+		return
+	}
+	metricType := in.GetType()
+	switch metricType {
+	case dto.MetricType_COUNTER:
+		n, err = w.WriteString(" counter\n")
+	case dto.MetricType_GAUGE:
+		n, err = w.WriteString(" gauge\n")
+	case dto.MetricType_SUMMARY:
+		n, err = w.WriteString(" summary\n")
+	case dto.MetricType_UNTYPED:
+		n, err = w.WriteString(" untyped\n")
+	case dto.MetricType_HISTOGRAM:
+		n, err = w.WriteString(" histogram\n")
+	default:
+		return written, fmt.Errorf("unknown metric type %s", metricType.String())
+	}
+	written += n
+	if err != nil {
+		return
 	}
 
 	// Finally the samples, one line for each.
@@ -75,9 +160,8 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
 				)
 			}
 			n, err = writeSample(
-				name, metric, "", "",
+				w, name, "", metric, "", 0,
 				metric.Counter.GetValue(),
-				out,
 			)
 		case dto.MetricType_GAUGE:
 			if metric.Gauge == nil {
@@ -86,9 +170,8 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
 				)
 			}
 			n, err = writeSample(
-				name, metric, "", "",
+				w, name, "", metric, "", 0,
 				metric.Gauge.GetValue(),
-				out,
 			)
 		case dto.MetricType_UNTYPED:
 			if metric.Untyped == nil {
@@ -97,9 +180,8 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
 				)
 			}
 			n, err = writeSample(
-				name, metric, "", "",
+				w, name, "", metric, "", 0,
 				metric.Untyped.GetValue(),
-				out,
 			)
 		case dto.MetricType_SUMMARY:
 			if metric.Summary == nil {
@@ -109,29 +191,26 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
 			}
 			for _, q := range metric.Summary.Quantile {
 				n, err = writeSample(
-					name, metric,
-					model.QuantileLabel, fmt.Sprint(q.GetQuantile()),
+					w, name, "", metric,
+					model.QuantileLabel, q.GetQuantile(),
 					q.GetValue(),
-					out,
 				)
 				written += n
 				if err != nil {
-					return written, err
+					return
 				}
 			}
 			n, err = writeSample(
-				name+"_sum", metric, "", "",
+				w, name, "_sum", metric, "", 0,
 				metric.Summary.GetSampleSum(),
-				out,
 			)
-			if err != nil {
-				return written, err
-			}
 			written += n
+			if err != nil {
+				return
+			}
 			n, err = writeSample(
-				name+"_count", metric, "", "",
+				w, name, "_count", metric, "", 0,
 				float64(metric.Summary.GetSampleCount()),
-				out,
 			)
 		case dto.MetricType_HISTOGRAM:
 			if metric.Histogram == nil {
@@ -140,46 +219,42 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
 				)
 			}
 			infSeen := false
-			for _, q := range metric.Histogram.Bucket {
+			for _, b := range metric.Histogram.Bucket {
 				n, err = writeSample(
-					name+"_bucket", metric,
-					model.BucketLabel, fmt.Sprint(q.GetUpperBound()),
-					float64(q.GetCumulativeCount()),
-					out,
+					w, name, "_bucket", metric,
+					model.BucketLabel, b.GetUpperBound(),
+					float64(b.GetCumulativeCount()),
 				)
 				written += n
 				if err != nil {
-					return written, err
+					return
 				}
-				if math.IsInf(q.GetUpperBound(), +1) {
+				if math.IsInf(b.GetUpperBound(), +1) {
 					infSeen = true
 				}
 			}
 			if !infSeen {
 				n, err = writeSample(
-					name+"_bucket", metric,
-					model.BucketLabel, "+Inf",
+					w, name, "_bucket", metric,
+					model.BucketLabel, math.Inf(+1),
 					float64(metric.Histogram.GetSampleCount()),
-					out,
 				)
-				if err != nil {
-					return written, err
-				}
 				written += n
+				if err != nil {
+					return
+				}
 			}
 			n, err = writeSample(
-				name+"_sum", metric, "", "",
+				w, name, "_sum", metric, "", 0,
 				metric.Histogram.GetSampleSum(),
-				out,
 			)
-			if err != nil {
-				return written, err
-			}
 			written += n
+			if err != nil {
+				return
+			}
 			n, err = writeSample(
-				name+"_count", metric, "", "",
+				w, name, "_count", metric, "", 0,
 				float64(metric.Histogram.GetSampleCount()),
-				out,
 			)
 		default:
 			return written, fmt.Errorf(
@@ -188,116 +263,203 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
 		}
 		written += n
 		if err != nil {
-			return written, err
+			return
 		}
 	}
-	return written, nil
+	return
 }
 
-// writeSample writes a single sample in text format to out, given the metric
+// writeSample writes a single sample in text format to w, given the metric
 // name, the metric proto message itself, optionally an additional label name
-// and value (use empty strings if not required), and the value. The function
-// returns the number of bytes written and any error encountered.
+// with a float64 value (use empty string as label name if not required), and
+// the value. The function returns the number of bytes written and any error
+// encountered.
 func writeSample(
-	name string,
+	w enhancedWriter,
+	name, suffix string,
 	metric *dto.Metric,
-	additionalLabelName, additionalLabelValue string,
+	additionalLabelName string, additionalLabelValue float64,
 	value float64,
-	out io.Writer,
 ) (int, error) {
 	var written int
-	n, err := fmt.Fprint(out, name)
+	n, err := w.WriteString(name)
 	written += n
 	if err != nil {
 		return written, err
 	}
-	n, err = labelPairsToText(
-		metric.Label,
-		additionalLabelName, additionalLabelValue,
-		out,
-	)
-	written += n
-	if err != nil {
-		return written, err
-	}
-	n, err = fmt.Fprintf(out, " %v", value)
-	written += n
-	if err != nil {
-		return written, err
-	}
-	if metric.TimestampMs != nil {
-		n, err = fmt.Fprintf(out, " %v", *metric.TimestampMs)
+	if suffix != "" {
+		n, err = w.WriteString(suffix)
 		written += n
 		if err != nil {
 			return written, err
 		}
 	}
-	n, err = out.Write([]byte{'\n'})
+	n, err = writeLabelPairs(
+		w, metric.Label, additionalLabelName, additionalLabelValue,
+	)
 	written += n
 	if err != nil {
 		return written, err
 	}
+	err = w.WriteByte(' ')
+	written++
+	if err != nil {
+		return written, err
+	}
+	n, err = writeFloat(w, value)
+	written += n
+	if err != nil {
+		return written, err
+	}
+	if metric.TimestampMs != nil {
+		err = w.WriteByte(' ')
+		written++
+		if err != nil {
+			return written, err
+		}
+		n, err = writeInt(w, *metric.TimestampMs)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+	err = w.WriteByte('\n')
+	written++
+	if err != nil {
+		return written, err
+	}
 	return written, nil
 }
 
-// labelPairsToText converts a slice of LabelPair proto messages plus the
+// writeLabelPairs converts a slice of LabelPair proto messages plus the
 // explicitly given additional label pair into text formatted as required by the
-// text format and writes it to 'out'. An empty slice in combination with an
-// empty string 'additionalLabelName' results in nothing being
-// written. Otherwise, the label pairs are written, escaped as required by the
-// text format, and enclosed in '{...}'. The function returns the number of
-// bytes written and any error encountered.
-func labelPairsToText(
+// text format and writes it to 'w'. An empty slice in combination with an empty
+// string 'additionalLabelName' results in nothing being written. Otherwise, the
+// label pairs are written, escaped as required by the text format, and enclosed
+// in '{...}'. The function returns the number of bytes written and any error
+// encountered.
+func writeLabelPairs(
+	w enhancedWriter,
 	in []*dto.LabelPair,
-	additionalLabelName, additionalLabelValue string,
-	out io.Writer,
+	additionalLabelName string, additionalLabelValue float64,
 ) (int, error) {
 	if len(in) == 0 && additionalLabelName == "" {
 		return 0, nil
 	}
-	var written int
-	separator := '{'
+	var (
+		written   int
+		separator byte = '{'
+	)
 	for _, lp := range in {
-		n, err := fmt.Fprintf(
-			out, `%c%s="%s"`,
-			separator, lp.GetName(), escapeString(lp.GetValue(), true),
-		)
+		err := w.WriteByte(separator)
+		written++
+		if err != nil {
+			return written, err
+		}
+		n, err := w.WriteString(lp.GetName())
 		written += n
 		if err != nil {
 			return written, err
 		}
+		n, err = w.WriteString(`="`)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = writeEscapedString(w, lp.GetValue(), true)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		err = w.WriteByte('"')
+		written++
+		if err != nil {
+			return written, err
+		}
 		separator = ','
 	}
 	if additionalLabelName != "" {
-		n, err := fmt.Fprintf(
-			out, `%c%s="%s"`,
-			separator, additionalLabelName,
-			escapeString(additionalLabelValue, true),
-		)
+		err := w.WriteByte(separator)
+		written++
+		if err != nil {
+			return written, err
+		}
+		n, err := w.WriteString(additionalLabelName)
 		written += n
 		if err != nil {
 			return written, err
 		}
+		n, err = w.WriteString(`="`)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = writeFloat(w, additionalLabelValue)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		err = w.WriteByte('"')
+		written++
+		if err != nil {
+			return written, err
+		}
 	}
-	n, err := out.Write([]byte{'}'})
-	written += n
+	err := w.WriteByte('}')
+	written++
 	if err != nil {
 		return written, err
 	}
 	return written, nil
 }
 
+// writeEscapedString replaces '\' by '\\', new line character by '\n', and - if
+// includeDoubleQuote is true - '"' by '\"'.
 var (
-	escape                = strings.NewReplacer("\\", `\\`, "\n", `\n`)
-	escapeWithDoubleQuote = strings.NewReplacer("\\", `\\`, "\n", `\n`, "\"", `\"`)
+	escaper       = strings.NewReplacer("\\", `\\`, "\n", `\n`)
+	quotedEscaper = strings.NewReplacer("\\", `\\`, "\n", `\n`, "\"", `\"`)
 )
 
-// escapeString replaces '\' by '\\', new line character by '\n', and - if
-// includeDoubleQuote is true - '"' by '\"'.
-func escapeString(v string, includeDoubleQuote bool) string {
+func writeEscapedString(w enhancedWriter, v string, includeDoubleQuote bool) (int, error) {
 	if includeDoubleQuote {
-		return escapeWithDoubleQuote.Replace(v)
+		return quotedEscaper.WriteString(w, v)
 	}
-
-	return escape.Replace(v)
+	return escaper.WriteString(w, v)
+}
+
+// writeFloat is equivalent to fmt.Fprint with a float64 argument but hardcodes
+// a few common cases for increased efficiency. For non-hardcoded cases, it uses
+// strconv.AppendFloat to avoid allocations, similar to writeInt.
+func writeFloat(w enhancedWriter, f float64) (int, error) {
+	switch {
+	case f == 1:
+		return 1, w.WriteByte('1')
+	case f == 0:
+		return 1, w.WriteByte('0')
+	case f == -1:
+		return w.WriteString("-1")
+	case math.IsNaN(f):
+		return w.WriteString("NaN")
+	case math.IsInf(f, +1):
+		return w.WriteString("+Inf")
+	case math.IsInf(f, -1):
+		return w.WriteString("-Inf")
+	default:
+		bp := numBufPool.Get().(*[]byte)
+		*bp = strconv.AppendFloat((*bp)[:0], f, 'g', -1, 64)
+		written, err := w.Write(*bp)
+		numBufPool.Put(bp)
+		return written, err
+	}
+}
+
+// writeInt is equivalent to fmt.Fprint with an int64 argument but uses
+// strconv.AppendInt with a byte slice taken from a sync.Pool to avoid
+// allocations.
+func writeInt(w enhancedWriter, i int64) (int, error) {
+	bp := numBufPool.Get().(*[]byte)
+	*bp = strconv.AppendInt((*bp)[:0], i, 10)
+	written, err := w.Write(*bp)
+	numBufPool.Put(bp)
+	return written, err
 }

vendor/github.com/prometheus/common/expfmt/text_parse.go

@@ -325,7 +325,7 @@ func (p *TextParser) startLabelValue() stateFn {
 	// - Other labels have to be added to currentLabels for signature calculation.
 	if p.currentMF.GetType() == dto.MetricType_SUMMARY {
 		if p.currentLabelPair.GetName() == model.QuantileLabel {
-			if p.currentQuantile, p.err = strconv.ParseFloat(p.currentLabelPair.GetValue(), 64); p.err != nil {
+			if p.currentQuantile, p.err = parseFloat(p.currentLabelPair.GetValue()); p.err != nil {
 				// Create a more helpful error message.
 				p.parseError(fmt.Sprintf("expected float as value for 'quantile' label, got %q", p.currentLabelPair.GetValue()))
 				return nil
@@ -337,7 +337,7 @@ func (p *TextParser) startLabelValue() stateFn {
 	// Similar special treatment of histograms.
 	if p.currentMF.GetType() == dto.MetricType_HISTOGRAM {
 		if p.currentLabelPair.GetName() == model.BucketLabel {
-			if p.currentBucket, p.err = strconv.ParseFloat(p.currentLabelPair.GetValue(), 64); p.err != nil {
+			if p.currentBucket, p.err = parseFloat(p.currentLabelPair.GetValue()); p.err != nil {
 				// Create a more helpful error message.
 				p.parseError(fmt.Sprintf("expected float as value for 'le' label, got %q", p.currentLabelPair.GetValue()))
 				return nil
@@ -359,7 +359,7 @@ func (p *TextParser) startLabelValue() stateFn {
 		}
 		return p.readingValue
 	default:
-		p.parseError(fmt.Sprintf("unexpected end of label value %q", p.currentLabelPair.Value))
+		p.parseError(fmt.Sprintf("unexpected end of label value %q", p.currentLabelPair.GetValue()))
 		return nil
 	}
 }
@@ -392,7 +392,7 @@ func (p *TextParser) readingValue() stateFn {
 	if p.readTokenUntilWhitespace(); p.err != nil {
 		return nil // Unexpected end of input.
 	}
-	value, err := strconv.ParseFloat(p.currentToken.String(), 64)
+	value, err := parseFloat(p.currentToken.String())
 	if err != nil {
 		// Create a more helpful error message.
 		p.parseError(fmt.Sprintf("expected float as value, got %q", p.currentToken.String()))
@@ -755,3 +755,10 @@ func histogramMetricName(name string) string {
 		return name
 	}
 }
+
+func parseFloat(s string) (float64, error) {
+	if strings.ContainsAny(s, "pP_") {
+		return 0, fmt.Errorf("unsupported character in float")
+	}
+	return strconv.ParseFloat(s, 64)
+}

vendor/github.com/prometheus/common/go.mod

@@ -0,0 +1,22 @@
+module github.com/prometheus/common
+
+require (
+	github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751 // indirect
+	github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4 // indirect
+	github.com/go-kit/kit v0.9.0
+	github.com/go-logfmt/logfmt v0.4.0 // indirect
+	github.com/golang/protobuf v1.3.2
+	github.com/julienschmidt/httprouter v1.2.0
+	github.com/matttproud/golang_protobuf_extensions v1.0.1
+	github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223
+	github.com/pkg/errors v0.8.1
+	github.com/prometheus/client_golang v1.0.0
+	github.com/prometheus/client_model v0.2.0
+	github.com/sirupsen/logrus v1.4.2
+	golang.org/x/net v0.0.0-20190613194153-d28f0bde5980 // indirect
+	golang.org/x/sys v0.0.0-20190422165155-953cdadca894
+	gopkg.in/alecthomas/kingpin.v2 v2.2.6
+	gopkg.in/yaml.v2 v2.2.4
+)
+
+go 1.11

vendor/github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg/autoneg.go

@@ -1,12 +1,12 @@
 /*
+Copyright (c) 2011, Open Knowledge Foundation Ltd.
+All rights reserved.
+
 HTTP Content-Type Autonegotiation.
 
 The functions in this package implement the behaviour specified in
 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
 
-Copyright (c) 2011, Open Knowledge Foundation Ltd.
-All rights reserved.
-
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are
 met:

vendor/github.com/prometheus/common/model/metric.go

@@ -21,7 +21,6 @@ import (
 )
 
 var (
-	separator = []byte{0}
 	// MetricNameRE is a regular expression matching valid metric
 	// names. Note that the IsValidMetricName function performs the same
 	// check but faster than a match with this regular expression.

vendor/github.com/prometheus/common/model/time.go

@@ -43,7 +43,7 @@ const (
 // (1970-01-01 00:00 UTC) excluding leap seconds.
 type Time int64
 
-// Interval describes and interval between two timestamps.
+// Interval describes an interval between two timestamps.
 type Interval struct {
 	Start, End Time
 }
@@ -150,7 +150,13 @@ func (t *Time) UnmarshalJSON(b []byte) error {
 			return err
 		}
 
-		*t = Time(v + va)
+		// If the value was something like -0.1 the negative is lost in the
+		// parsing because of the leading zero, this ensures that we capture it.
+		if len(p[0]) > 0 && p[0][0] == '-' && v+va > 0 {
+			*t = Time(v+va) * -1
+		} else {
+			*t = Time(v + va)
+		}
 
 	default:
 		return fmt.Errorf("invalid time %q", string(b))

vendor/github.com/prometheus/procfs/README.md

@@ -1,7 +1,7 @@
 # procfs
 
-This procfs package provides functions to retrieve system, kernel and process
-metrics from the pseudo-filesystem proc.
+This package provides functions to retrieve system, kernel, and process
+metrics from the pseudo-filesystems /proc and /sys.
 
 *WARNING*: This package is a work in progress. Its API may still break in
 backwards-incompatible ways without warnings. Use it at your own risk.
@@ -9,3 +9,53 @@ backwards-incompatible ways without warnings. Use it at your own risk.
 [![GoDoc](https://godoc.org/github.com/prometheus/procfs?status.png)](https://godoc.org/github.com/prometheus/procfs)
 [![Build Status](https://travis-ci.org/prometheus/procfs.svg?branch=master)](https://travis-ci.org/prometheus/procfs)
 [![Go Report Card](https://goreportcard.com/badge/github.com/prometheus/procfs)](https://goreportcard.com/report/github.com/prometheus/procfs)
+
+## Usage
+
+The procfs library is organized by packages based on whether the gathered data is coming from
+/proc, /sys, or both.  Each package contains an `FS` type which represents the path to either /proc, 
+/sys, or both.  For example, cpu statistics are gathered from
+`/proc/stat` and are available via the root procfs package.  First, the proc filesystem mount
+point is initialized, and then the stat information is read.
+
+```go
+fs, err := procfs.NewFS("/proc")
+stats, err := fs.Stat()
+```
+
+Some sub-packages such as `blockdevice`, require access to both the proc and sys filesystems.
+
+```go
+    fs, err := blockdevice.NewFS("/proc", "/sys")
+    stats, err := fs.ProcDiskstats()
+```
+
+## Package Organization
+
+The packages in this project are organized according to (1) whether the data comes from the `/proc` or
+`/sys` filesystem and (2) the type of information being retrieved.  For example, most process information
+can be gathered from the functions in the root `procfs` package.  Information about block devices such as disk drives
+is available in the `blockdevices` sub-package.
+
+## Building and Testing
+
+The procfs library is intended to be built as part of another application, so there are no distributable binaries.  
+However, most of the API includes unit tests which can be run with `make test`.
+
+### Updating Test Fixtures
+
+The procfs library includes a set of test fixtures which include many example files from
+the `/proc` and `/sys` filesystems.  These fixtures are included as a [ttar](https://github.com/ideaship/ttar) file
+which is extracted automatically during testing.  To add/update the test fixtures, first
+ensure the `fixtures` directory is up to date by removing the existing directory and then
+extracting the ttar file using `make fixtures/.unpacked` or just `make test`.
+
+```bash
+rm -rf fixtures
+make test
+```
+
+Next, make the required changes to the extracted files in the `fixtures` directory.  When
+the changes are complete, run `make update_fixtures` to create a new `fixtures.ttar` file
+based on the updated `fixtures` directory.  And finally, verify the changes using
+`git diff fixtures.ttar`.

vendor/github.com/prometheus/procfs/arp.go

@@ -0,0 +1,85 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net"
+	"strings"
+)
+
+// ARPEntry contains a single row of the columnar data represented in
+// /proc/net/arp.
+type ARPEntry struct {
+	// IP address
+	IPAddr net.IP
+	// MAC address
+	HWAddr net.HardwareAddr
+	// Name of the device
+	Device string
+}
+
+// GatherARPEntries retrieves all the ARP entries, parse the relevant columns,
+// and then return a slice of ARPEntry's.
+func (fs FS) GatherARPEntries() ([]ARPEntry, error) {
+	data, err := ioutil.ReadFile(fs.proc.Path("net/arp"))
+	if err != nil {
+		return nil, fmt.Errorf("error reading arp %s: %s", fs.proc.Path("net/arp"), err)
+	}
+
+	return parseARPEntries(data)
+}
+
+func parseARPEntries(data []byte) ([]ARPEntry, error) {
+	lines := strings.Split(string(data), "\n")
+	entries := make([]ARPEntry, 0)
+	var err error
+	const (
+		expectedDataWidth   = 6
+		expectedHeaderWidth = 9
+	)
+	for _, line := range lines {
+		columns := strings.Fields(line)
+		width := len(columns)
+
+		if width == expectedHeaderWidth || width == 0 {
+			continue
+		} else if width == expectedDataWidth {
+			entry, err := parseARPEntry(columns)
+			if err != nil {
+				return []ARPEntry{}, fmt.Errorf("failed to parse ARP entry: %s", err)
+			}
+			entries = append(entries, entry)
+		} else {
+			return []ARPEntry{}, fmt.Errorf("%d columns were detected, but %d were expected", width, expectedDataWidth)
+		}
+
+	}
+
+	return entries, err
+}
+
+func parseARPEntry(columns []string) (ARPEntry, error) {
+	ip := net.ParseIP(columns[0])
+	mac := net.HardwareAddr(columns[3])
+
+	entry := ARPEntry{
+		IPAddr: ip,
+		HWAddr: mac,
+		Device: columns[5],
+	}
+
+	return entry, nil
+}

vendor/github.com/prometheus/procfs/buddyinfo.go

@@ -31,19 +31,9 @@ type BuddyInfo struct {
 	Sizes []float64
 }
 
-// NewBuddyInfo reads the buddyinfo statistics.
-func NewBuddyInfo() ([]BuddyInfo, error) {
-	fs, err := NewFS(DefaultMountPoint)
-	if err != nil {
-		return nil, err
-	}
-
-	return fs.NewBuddyInfo()
-}
-
-// NewBuddyInfo reads the buddyinfo statistics from the specified `proc` filesystem.
-func (fs FS) NewBuddyInfo() ([]BuddyInfo, error) {
-	file, err := os.Open(fs.Path("buddyinfo"))
+// BuddyInfo reads the buddyinfo statistics from the specified `proc` filesystem.
+func (fs FS) BuddyInfo() ([]BuddyInfo, error) {
+	file, err := os.Open(fs.proc.Path("buddyinfo"))
 	if err != nil {
 		return nil, err
 	}

vendor/github.com/prometheus/procfs/cpuinfo.go

@@ -0,0 +1,167 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// CPUInfo contains general information about a system CPU found in /proc/cpuinfo
+type CPUInfo struct {
+	Processor       uint
+	VendorID        string
+	CPUFamily       string
+	Model           string
+	ModelName       string
+	Stepping        string
+	Microcode       string
+	CPUMHz          float64
+	CacheSize       string
+	PhysicalID      string
+	Siblings        uint
+	CoreID          string
+	CPUCores        uint
+	APICID          string
+	InitialAPICID   string
+	FPU             string
+	FPUException    string
+	CPUIDLevel      uint
+	WP              string
+	Flags           []string
+	Bugs            []string
+	BogoMips        float64
+	CLFlushSize     uint
+	CacheAlignment  uint
+	AddressSizes    string
+	PowerManagement string
+}
+
+// CPUInfo returns information about current system CPUs.
+// See https://www.kernel.org/doc/Documentation/filesystems/proc.txt
+func (fs FS) CPUInfo() ([]CPUInfo, error) {
+	data, err := util.ReadFileNoStat(fs.proc.Path("cpuinfo"))
+	if err != nil {
+		return nil, err
+	}
+	return parseCPUInfo(data)
+}
+
+// parseCPUInfo parses data from /proc/cpuinfo
+func parseCPUInfo(info []byte) ([]CPUInfo, error) {
+	cpuinfo := []CPUInfo{}
+	i := -1
+	scanner := bufio.NewScanner(bytes.NewReader(info))
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.TrimSpace(line) == "" {
+			continue
+		}
+		field := strings.SplitN(line, ": ", 2)
+		switch strings.TrimSpace(field[0]) {
+		case "processor":
+			cpuinfo = append(cpuinfo, CPUInfo{}) // start of the next processor
+			i++
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].Processor = uint(v)
+		case "vendor_id":
+			cpuinfo[i].VendorID = field[1]
+		case "cpu family":
+			cpuinfo[i].CPUFamily = field[1]
+		case "model":
+			cpuinfo[i].Model = field[1]
+		case "model name":
+			cpuinfo[i].ModelName = field[1]
+		case "stepping":
+			cpuinfo[i].Stepping = field[1]
+		case "microcode":
+			cpuinfo[i].Microcode = field[1]
+		case "cpu MHz":
+			v, err := strconv.ParseFloat(field[1], 64)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].CPUMHz = v
+		case "cache size":
+			cpuinfo[i].CacheSize = field[1]
+		case "physical id":
+			cpuinfo[i].PhysicalID = field[1]
+		case "siblings":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].Siblings = uint(v)
+		case "core id":
+			cpuinfo[i].CoreID = field[1]
+		case "cpu cores":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].CPUCores = uint(v)
+		case "apicid":
+			cpuinfo[i].APICID = field[1]
+		case "initial apicid":
+			cpuinfo[i].InitialAPICID = field[1]
+		case "fpu":
+			cpuinfo[i].FPU = field[1]
+		case "fpu_exception":
+			cpuinfo[i].FPUException = field[1]
+		case "cpuid level":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].CPUIDLevel = uint(v)
+		case "wp":
+			cpuinfo[i].WP = field[1]
+		case "flags":
+			cpuinfo[i].Flags = strings.Fields(field[1])
+		case "bugs":
+			cpuinfo[i].Bugs = strings.Fields(field[1])
+		case "bogomips":
+			v, err := strconv.ParseFloat(field[1], 64)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].BogoMips = v
+		case "clflush size":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].CLFlushSize = uint(v)
+		case "cache_alignment":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].CacheAlignment = uint(v)
+		case "address sizes":
+			cpuinfo[i].AddressSizes = field[1]
+		case "power management":
+			cpuinfo[i].PowerManagement = field[1]
+		}
+	}
+	return cpuinfo, nil
+
+}

vendor/github.com/prometheus/procfs/crypto.go

@@ -0,0 +1,153 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// Crypto holds info parsed from /proc/crypto.
+type Crypto struct {
+	Alignmask   *uint64
+	Async       bool
+	Blocksize   *uint64
+	Chunksize   *uint64
+	Ctxsize     *uint64
+	Digestsize  *uint64
+	Driver      string
+	Geniv       string
+	Internal    string
+	Ivsize      *uint64
+	Maxauthsize *uint64
+	MaxKeysize  *uint64
+	MinKeysize  *uint64
+	Module      string
+	Name        string
+	Priority    *int64
+	Refcnt      *int64
+	Seedsize    *uint64
+	Selftest    string
+	Type        string
+	Walksize    *uint64
+}
+
+// Crypto parses an crypto-file (/proc/crypto) and returns a slice of
+// structs containing the relevant info.  More information available here:
+// https://kernel.readthedocs.io/en/sphinx-samples/crypto-API.html
+func (fs FS) Crypto() ([]Crypto, error) {
+	path := fs.proc.Path("crypto")
+	b, err := util.ReadFileNoStat(path)
+	if err != nil {
+		return nil, fmt.Errorf("error reading crypto %s: %s", path, err)
+	}
+
+	crypto, err := parseCrypto(bytes.NewReader(b))
+	if err != nil {
+		return nil, fmt.Errorf("error parsing crypto %s: %s", path, err)
+	}
+
+	return crypto, nil
+}
+
+// parseCrypto parses a /proc/crypto stream into Crypto elements.
+func parseCrypto(r io.Reader) ([]Crypto, error) {
+	var out []Crypto
+
+	s := bufio.NewScanner(r)
+	for s.Scan() {
+		text := s.Text()
+		switch {
+		case strings.HasPrefix(text, "name"):
+			// Each crypto element begins with its name.
+			out = append(out, Crypto{})
+		case text == "":
+			continue
+		}
+
+		kv := strings.Split(text, ":")
+		if len(kv) != 2 {
+			return nil, fmt.Errorf("malformed crypto line: %q", text)
+		}
+
+		k := strings.TrimSpace(kv[0])
+		v := strings.TrimSpace(kv[1])
+
+		// Parse the key/value pair into the currently focused element.
+		c := &out[len(out)-1]
+		if err := c.parseKV(k, v); err != nil {
+			return nil, err
+		}
+	}
+
+	if err := s.Err(); err != nil {
+		return nil, err
+	}
+
+	return out, nil
+}
+
+// parseKV parses a key/value pair into the appropriate field of c.
+func (c *Crypto) parseKV(k, v string) error {
+	vp := util.NewValueParser(v)
+
+	switch k {
+	case "async":
+		// Interpret literal yes as true.
+		c.Async = v == "yes"
+	case "blocksize":
+		c.Blocksize = vp.PUInt64()
+	case "chunksize":
+		c.Chunksize = vp.PUInt64()
+	case "digestsize":
+		c.Digestsize = vp.PUInt64()
+	case "driver":
+		c.Driver = v
+	case "geniv":
+		c.Geniv = v
+	case "internal":
+		c.Internal = v
+	case "ivsize":
+		c.Ivsize = vp.PUInt64()
+	case "maxauthsize":
+		c.Maxauthsize = vp.PUInt64()
+	case "max keysize":
+		c.MaxKeysize = vp.PUInt64()
+	case "min keysize":
+		c.MinKeysize = vp.PUInt64()
+	case "module":
+		c.Module = v
+	case "name":
+		c.Name = v
+	case "priority":
+		c.Priority = vp.PInt64()
+	case "refcnt":
+		c.Refcnt = vp.PInt64()
+	case "seedsize":
+		c.Seedsize = vp.PUInt64()
+	case "selftest":
+		c.Selftest = v
+	case "type":
+		c.Type = v
+	case "walksize":
+		c.Walksize = vp.PUInt64()
+	}
+
+	return vp.Err()
+}

vendor/github.com/prometheus/procfs/fs.go

@@ -14,69 +14,30 @@
 package procfs
 
 import (
-	"fmt"
-	"os"
-	"path"
-
-	"github.com/prometheus/procfs/nfs"
-	"github.com/prometheus/procfs/xfs"
+	"github.com/prometheus/procfs/internal/fs"
 )
 
-// FS represents the pseudo-filesystem proc, which provides an interface to
+// FS represents the pseudo-filesystem sys, which provides an interface to
 // kernel data structures.
-type FS string
+type FS struct {
+	proc fs.FS
+}
 
 // DefaultMountPoint is the common mount point of the proc filesystem.
-const DefaultMountPoint = "/proc"
+const DefaultMountPoint = fs.DefaultProcMountPoint
 
-// NewFS returns a new FS mounted under the given mountPoint. It will error
-// if the mount point can't be read.
+// NewDefaultFS returns a new proc FS mounted under the default proc mountPoint.
+// It will error if the mount point directory can't be read or is a file.
+func NewDefaultFS() (FS, error) {
+	return NewFS(DefaultMountPoint)
+}
+
+// NewFS returns a new proc FS mounted under the given proc mountPoint. It will error
+// if the mount point directory can't be read or is a file.
 func NewFS(mountPoint string) (FS, error) {
-	info, err := os.Stat(mountPoint)
+	fs, err := fs.NewFS(mountPoint)
 	if err != nil {
-		return "", fmt.Errorf("could not read %s: %s", mountPoint, err)
+		return FS{}, err
 	}
-	if !info.IsDir() {
-		return "", fmt.Errorf("mount point %s is not a directory", mountPoint)
-	}
-
-	return FS(mountPoint), nil
-}
-
-// Path returns the path of the given subsystem relative to the procfs root.
-func (fs FS) Path(p ...string) string {
-	return path.Join(append([]string{string(fs)}, p...)...)
-}
-
-// XFSStats retrieves XFS filesystem runtime statistics.
-func (fs FS) XFSStats() (*xfs.Stats, error) {
-	f, err := os.Open(fs.Path("fs/xfs/stat"))
-	if err != nil {
-		return nil, err
-	}
-	defer f.Close()
-
-	return xfs.ParseStats(f)
-}
-
-// NFSClientRPCStats retrieves NFS client RPC statistics.
-func (fs FS) NFSClientRPCStats() (*nfs.ClientRPCStats, error) {
-	f, err := os.Open(fs.Path("net/rpc/nfs"))
-	if err != nil {
-		return nil, err
-	}
-	defer f.Close()
-
-	return nfs.ParseClientRPCStats(f)
-}
-
-// NFSdServerRPCStats retrieves NFS daemon RPC statistics.
-func (fs FS) NFSdServerRPCStats() (*nfs.ServerRPCStats, error) {
-	f, err := os.Open(fs.Path("net/rpc/nfsd"))
-	if err != nil {
-		return nil, err
-	}
-	defer f.Close()
-
-	return nfs.ParseServerRPCStats(f)
+	return FS{fs}, nil
 }

vendor/github.com/prometheus/procfs/go.mod

@@ -0,0 +1,9 @@
+module github.com/prometheus/procfs
+
+go 1.12
+
+require (
+	github.com/google/go-cmp v0.3.1
+	golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e
+	golang.org/x/sys v0.0.0-20200106162015-b016eb3dc98e
+)

vendor/github.com/prometheus/procfs/internal/fs/fs.go

@@ -0,0 +1,55 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fs
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+const (
+	// DefaultProcMountPoint is the common mount point of the proc filesystem.
+	DefaultProcMountPoint = "/proc"
+
+	// DefaultSysMountPoint is the common mount point of the sys filesystem.
+	DefaultSysMountPoint = "/sys"
+
+	// DefaultConfigfsMountPoint is the common mount point of the configfs
+	DefaultConfigfsMountPoint = "/sys/kernel/config"
+)
+
+// FS represents a pseudo-filesystem, normally /proc or /sys, which provides an
+// interface to kernel data structures.
+type FS string
+
+// NewFS returns a new FS mounted under the given mountPoint. It will error
+// if the mount point can't be read.
+func NewFS(mountPoint string) (FS, error) {
+	info, err := os.Stat(mountPoint)
+	if err != nil {
+		return "", fmt.Errorf("could not read %s: %s", mountPoint, err)
+	}
+	if !info.IsDir() {
+		return "", fmt.Errorf("mount point %s is not a directory", mountPoint)
+	}
+
+	return FS(mountPoint), nil
+}
+
+// Path appends the given path elements to the filesystem path, adding separators
+// as necessary.
+func (fs FS) Path(p ...string) string {
+	return filepath.Join(append([]string{string(fs)}, p...)...)
+}

vendor/github.com/prometheus/procfs/internal/util/parse.go

@@ -13,7 +13,11 @@
 
 package util
 
-import "strconv"
+import (
+	"io/ioutil"
+	"strconv"
+	"strings"
+)
 
 // ParseUint32s parses a slice of strings into a slice of uint32s.
 func ParseUint32s(ss []string) ([]uint32, error) {
@@ -44,3 +48,41 @@ func ParseUint64s(ss []string) ([]uint64, error) {
 
 	return us, nil
 }
+
+// ParsePInt64s parses a slice of strings into a slice of int64 pointers.
+func ParsePInt64s(ss []string) ([]*int64, error) {
+	us := make([]*int64, 0, len(ss))
+	for _, s := range ss {
+		u, err := strconv.ParseInt(s, 10, 64)
+		if err != nil {
+			return nil, err
+		}
+
+		us = append(us, &u)
+	}
+
+	return us, nil
+}
+
+// ReadUintFromFile reads a file and attempts to parse a uint64 from it.
+func ReadUintFromFile(path string) (uint64, error) {
+	data, err := ioutil.ReadFile(path)
+	if err != nil {
+		return 0, err
+	}
+	return strconv.ParseUint(strings.TrimSpace(string(data)), 10, 64)
+}
+
+// ParseBool parses a string into a boolean pointer.
+func ParseBool(b string) *bool {
+	var truth bool
+	switch b {
+	case "enabled":
+		truth = true
+	case "disabled":
+		truth = false
+	default:
+		return nil
+	}
+	return &truth
+}

vendor/github.com/prometheus/procfs/internal/util/readfile.go

@@ -0,0 +1,38 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package util
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+)
+
+// ReadFileNoStat uses ioutil.ReadAll to read contents of entire file.
+// This is similar to ioutil.ReadFile but without the call to os.Stat, because
+// many files in /proc and /sys report incorrect file sizes (either 0 or 4096).
+// Reads a max file size of 512kB.  For files larger than this, a scanner
+// should be used.
+func ReadFileNoStat(filename string) ([]byte, error) {
+	const maxBufferSize = 1024 * 512
+
+	f, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	reader := io.LimitReader(f, maxBufferSize)
+	return ioutil.ReadAll(reader)
+}

vendor/github.com/prometheus/procfs/internal/util/sysreadfile.go

@@ -0,0 +1,48 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux,!appengine
+
+package util
+
+import (
+	"bytes"
+	"os"
+	"syscall"
+)
+
+// SysReadFile is a simplified ioutil.ReadFile that invokes syscall.Read directly.
+// https://github.com/prometheus/node_exporter/pull/728/files
+//
+// Note that this function will not read files larger than 128 bytes.
+func SysReadFile(file string) (string, error) {
+	f, err := os.Open(file)
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+
+	// On some machines, hwmon drivers are broken and return EAGAIN.  This causes
+	// Go's ioutil.ReadFile implementation to poll forever.
+	//
+	// Since we either want to read data or bail immediately, do the simplest
+	// possible read using syscall directly.
+	const sysFileBufferSize = 128
+	b := make([]byte, sysFileBufferSize)
+	n, err := syscall.Read(int(f.Fd()), b)
+	if err != nil {
+		return "", err
+	}
+
+	return string(bytes.TrimSpace(b[:n])), nil
+}

vendor/github.com/prometheus/procfs/internal/util/sysreadfile_compat.go

@@ -0,0 +1,26 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux,appengine !linux
+
+package util
+
+import (
+	"fmt"
+)
+
+// SysReadFile is here implemented as a noop for builds that do not support
+// the read syscall. For example Windows, or Linux on Google App Engine.
+func SysReadFile(file string) (string, error) {
+	return "", fmt.Errorf("not supported on this platform")
+}

vendor/github.com/prometheus/procfs/internal/util/valueparser.go

@@ -0,0 +1,91 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package util
+
+import (
+	"strconv"
+)
+
+// TODO(mdlayher): util packages are an anti-pattern and this should be moved
+// somewhere else that is more focused in the future.
+
+// A ValueParser enables parsing a single string into a variety of data types
+// in a concise and safe way. The Err method must be invoked after invoking
+// any other methods to ensure a value was successfully parsed.
+type ValueParser struct {
+	v   string
+	err error
+}
+
+// NewValueParser creates a ValueParser using the input string.
+func NewValueParser(v string) *ValueParser {
+	return &ValueParser{v: v}
+}
+
+// Int interprets the underlying value as an int and returns that value.
+func (vp *ValueParser) Int() int { return int(vp.int64()) }
+
+// PInt64 interprets the underlying value as an int64 and returns a pointer to
+// that value.
+func (vp *ValueParser) PInt64() *int64 {
+	if vp.err != nil {
+		return nil
+	}
+
+	v := vp.int64()
+	return &v
+}
+
+// int64 interprets the underlying value as an int64 and returns that value.
+// TODO: export if/when necessary.
+func (vp *ValueParser) int64() int64 {
+	if vp.err != nil {
+		return 0
+	}
+
+	// A base value of zero makes ParseInt infer the correct base using the
+	// string's prefix, if any.
+	const base = 0
+	v, err := strconv.ParseInt(vp.v, base, 64)
+	if err != nil {
+		vp.err = err
+		return 0
+	}
+
+	return v
+}
+
+// PUInt64 interprets the underlying value as an uint64 and returns a pointer to
+// that value.
+func (vp *ValueParser) PUInt64() *uint64 {
+	if vp.err != nil {
+		return nil
+	}
+
+	// A base value of zero makes ParseInt infer the correct base using the
+	// string's prefix, if any.
+	const base = 0
+	v, err := strconv.ParseUint(vp.v, base, 64)
+	if err != nil {
+		vp.err = err
+		return nil
+	}
+
+	return &v
+}
+
+// Err returns the last error, if any, encountered by the ValueParser.
+func (vp *ValueParser) Err() error {
+	return vp.err
+}

vendor/github.com/prometheus/procfs/ipvs.go

@@ -15,6 +15,7 @@ package procfs
 
 import (
 	"bufio"
+	"bytes"
 	"encoding/hex"
 	"errors"
 	"fmt"
@@ -24,6 +25,8 @@ import (
 	"os"
 	"strconv"
 	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
 )
 
 // IPVSStats holds IPVS statistics, as exposed by the kernel in `/proc/net/ip_vs_stats`.
@@ -62,29 +65,18 @@ type IPVSBackendStatus struct {
 	Weight uint64
 }
 
-// NewIPVSStats reads the IPVS statistics.
-func NewIPVSStats() (IPVSStats, error) {
-	fs, err := NewFS(DefaultMountPoint)
+// IPVSStats reads the IPVS statistics from the specified `proc` filesystem.
+func (fs FS) IPVSStats() (IPVSStats, error) {
+	data, err := util.ReadFileNoStat(fs.proc.Path("net/ip_vs_stats"))
 	if err != nil {
 		return IPVSStats{}, err
 	}
 
-	return fs.NewIPVSStats()
-}
-
-// NewIPVSStats reads the IPVS statistics from the specified `proc` filesystem.
-func (fs FS) NewIPVSStats() (IPVSStats, error) {
-	file, err := os.Open(fs.Path("net/ip_vs_stats"))
-	if err != nil {
-		return IPVSStats{}, err
-	}
-	defer file.Close()
-
-	return parseIPVSStats(file)
+	return parseIPVSStats(bytes.NewReader(data))
 }
 
 // parseIPVSStats performs the actual parsing of `ip_vs_stats`.
-func parseIPVSStats(file io.Reader) (IPVSStats, error) {
+func parseIPVSStats(r io.Reader) (IPVSStats, error) {
 	var (
 		statContent []byte
 		statLines   []string
@@ -92,7 +84,7 @@ func parseIPVSStats(file io.Reader) (IPVSStats, error) {
 		stats       IPVSStats
 	)
 
-	statContent, err := ioutil.ReadAll(file)
+	statContent, err := ioutil.ReadAll(r)
 	if err != nil {
 		return IPVSStats{}, err
 	}
@@ -131,19 +123,9 @@ func parseIPVSStats(file io.Reader) (IPVSStats, error) {
 	return stats, nil
 }
 
-// NewIPVSBackendStatus reads and returns the status of all (virtual,real) server pairs.
-func NewIPVSBackendStatus() ([]IPVSBackendStatus, error) {
-	fs, err := NewFS(DefaultMountPoint)
-	if err != nil {
-		return []IPVSBackendStatus{}, err
-	}
-
-	return fs.NewIPVSBackendStatus()
-}
-
-// NewIPVSBackendStatus reads and returns the status of all (virtual,real) server pairs from the specified `proc` filesystem.
-func (fs FS) NewIPVSBackendStatus() ([]IPVSBackendStatus, error) {
-	file, err := os.Open(fs.Path("net/ip_vs"))
+// IPVSBackendStatus reads and returns the status of all (virtual,real) server pairs from the specified `proc` filesystem.
+func (fs FS) IPVSBackendStatus() ([]IPVSBackendStatus, error) {
+	file, err := os.Open(fs.proc.Path("net/ip_vs"))
 	if err != nil {
 		return nil, err
 	}

vendor/github.com/prometheus/procfs/loadavg.go

@@ -0,0 +1,62 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// LoadAvg represents an entry in /proc/loadavg
+type LoadAvg struct {
+	Load1  float64
+	Load5  float64
+	Load15 float64
+}
+
+// LoadAvg returns loadavg from /proc.
+func (fs FS) LoadAvg() (*LoadAvg, error) {
+	path := fs.proc.Path("loadavg")
+
+	data, err := util.ReadFileNoStat(path)
+	if err != nil {
+		return nil, err
+	}
+	return parseLoad(data)
+}
+
+// Parse /proc loadavg and return 1m, 5m and 15m.
+func parseLoad(loadavgBytes []byte) (*LoadAvg, error) {
+	loads := make([]float64, 3)
+	parts := strings.Fields(string(loadavgBytes))
+	if len(parts) < 3 {
+		return nil, fmt.Errorf("malformed loadavg line: too few fields in loadavg string: %s", string(loadavgBytes))
+	}
+
+	var err error
+	for i, load := range parts[0:3] {
+		loads[i], err = strconv.ParseFloat(load, 64)
+		if err != nil {
+			return nil, fmt.Errorf("could not parse load '%s': %s", load, err)
+		}
+	}
+	return &LoadAvg{
+		Load1:  loads[0],
+		Load5:  loads[1],
+		Load15: loads[2],
+	}, nil
+}

vendor/github.com/prometheus/procfs/mdstat.go

@@ -22,8 +22,8 @@ import (
 )
 
 var (
-	statuslineRE = regexp.MustCompile(`(\d+) blocks .*\[(\d+)/(\d+)\] \[[U_]+\]`)
-	buildlineRE  = regexp.MustCompile(`\((\d+)/\d+\)`)
+	statusLineRE   = regexp.MustCompile(`(\d+) blocks .*\[(\d+)/(\d+)\] \[[U_]+\]`)
+	recoveryLineRE = regexp.MustCompile(`\((\d+)/\d+\)`)
 )
 
 // MDStat holds info parsed from /proc/mdstat.
@@ -34,117 +34,160 @@ type MDStat struct {
 	ActivityState string
 	// Number of active disks.
 	DisksActive int64
-	// Total number of disks the device consists of.
+	// Total number of disks the device requires.
 	DisksTotal int64
+	// Number of failed disks.
+	DisksFailed int64
+	// Spare disks in the device.
+	DisksSpare int64
 	// Number of blocks the device holds.
 	BlocksTotal int64
 	// Number of blocks on the device that are in sync.
 	BlocksSynced int64
 }
 
-// ParseMDStat parses an mdstat-file and returns a struct with the relevant infos.
-func (fs FS) ParseMDStat() (mdstates []MDStat, err error) {
-	mdStatusFilePath := fs.Path("mdstat")
-	content, err := ioutil.ReadFile(mdStatusFilePath)
+// MDStat parses an mdstat-file (/proc/mdstat) and returns a slice of
+// structs containing the relevant info.  More information available here:
+// https://raid.wiki.kernel.org/index.php/Mdstat
+func (fs FS) MDStat() ([]MDStat, error) {
+	data, err := ioutil.ReadFile(fs.proc.Path("mdstat"))
 	if err != nil {
-		return []MDStat{}, fmt.Errorf("error parsing %s: %s", mdStatusFilePath, err)
+		return nil, fmt.Errorf("error parsing mdstat %s: %s", fs.proc.Path("mdstat"), err)
 	}
+	mdstat, err := parseMDStat(data)
+	if err != nil {
+		return nil, fmt.Errorf("error parsing mdstat %s: %s", fs.proc.Path("mdstat"), err)
+	}
+	return mdstat, nil
+}
 
-	mdStates := []MDStat{}
-	lines := strings.Split(string(content), "\n")
-	for i, l := range lines {
-		if l == "" {
-			continue
-		}
-		if l[0] == ' ' {
-			continue
-		}
-		if strings.HasPrefix(l, "Personalities") || strings.HasPrefix(l, "unused") {
+// parseMDStat parses data from mdstat file (/proc/mdstat) and returns a slice of
+// structs containing the relevant info.
+func parseMDStat(mdStatData []byte) ([]MDStat, error) {
+	mdStats := []MDStat{}
+	lines := strings.Split(string(mdStatData), "\n")
+
+	for i, line := range lines {
+		if strings.TrimSpace(line) == "" || line[0] == ' ' ||
+			strings.HasPrefix(line, "Personalities") ||
+			strings.HasPrefix(line, "unused") {
 			continue
 		}
 
-		mainLine := strings.Split(l, " ")
-		if len(mainLine) < 3 {
-			return mdStates, fmt.Errorf("error parsing mdline: %s", l)
+		deviceFields := strings.Fields(line)
+		if len(deviceFields) < 3 {
+			return nil, fmt.Errorf("not enough fields in mdline (expected at least 3): %s", line)
 		}
-		mdName := mainLine[0]
-		activityState := mainLine[2]
+		mdName := deviceFields[0] // mdx
+		state := deviceFields[2]  // active or inactive
 
 		if len(lines) <= i+3 {
-			return mdStates, fmt.Errorf(
-				"error parsing %s: too few lines for md device %s",
-				mdStatusFilePath,
+			return nil, fmt.Errorf(
+				"error parsing %s: too few lines for md device",
 				mdName,
 			)
 		}
 
-		active, total, size, err := evalStatusline(lines[i+1])
+		// Failed disks have the suffix (F) & Spare disks have the suffix (S).
+		fail := int64(strings.Count(line, "(F)"))
+		spare := int64(strings.Count(line, "(S)"))
+		active, total, size, err := evalStatusLine(lines[i], lines[i+1])
+
 		if err != nil {
-			return mdStates, fmt.Errorf("error parsing %s: %s", mdStatusFilePath, err)
+			return nil, fmt.Errorf("error parsing md device lines: %s", err)
 		}
 
-		// j is the line number of the syncing-line.
-		j := i + 2
+		syncLineIdx := i + 2
 		if strings.Contains(lines[i+2], "bitmap") { // skip bitmap line
-			j = i + 3
+			syncLineIdx++
 		}
 
 		// If device is syncing at the moment, get the number of currently
 		// synced bytes, otherwise that number equals the size of the device.
 		syncedBlocks := size
-		if strings.Contains(lines[j], "recovery") || strings.Contains(lines[j], "resync") {
-			syncedBlocks, err = evalBuildline(lines[j])
-			if err != nil {
-				return mdStates, fmt.Errorf("error parsing %s: %s", mdStatusFilePath, err)
+		recovering := strings.Contains(lines[syncLineIdx], "recovery")
+		resyncing := strings.Contains(lines[syncLineIdx], "resync")
+
+		// Append recovery and resyncing state info.
+		if recovering || resyncing {
+			if recovering {
+				state = "recovering"
+			} else {
+				state = "resyncing"
+			}
+
+			// Handle case when resync=PENDING or resync=DELAYED.
+			if strings.Contains(lines[syncLineIdx], "PENDING") ||
+				strings.Contains(lines[syncLineIdx], "DELAYED") {
+				syncedBlocks = 0
+			} else {
+				syncedBlocks, err = evalRecoveryLine(lines[syncLineIdx])
+				if err != nil {
+					return nil, fmt.Errorf("error parsing sync line in md device %s: %s", mdName, err)
+				}
 			}
 		}
 
-		mdStates = append(mdStates, MDStat{
+		mdStats = append(mdStats, MDStat{
 			Name:          mdName,
-			ActivityState: activityState,
+			ActivityState: state,
 			DisksActive:   active,
+			DisksFailed:   fail,
+			DisksSpare:    spare,
 			DisksTotal:    total,
 			BlocksTotal:   size,
 			BlocksSynced:  syncedBlocks,
 		})
 	}
 
-	return mdStates, nil
+	return mdStats, nil
 }
 
-func evalStatusline(statusline string) (active, total, size int64, err error) {
-	matches := statuslineRE.FindStringSubmatch(statusline)
-	if len(matches) != 4 {
-		return 0, 0, 0, fmt.Errorf("unexpected statusline: %s", statusline)
+func evalStatusLine(deviceLine, statusLine string) (active, total, size int64, err error) {
+
+	sizeStr := strings.Fields(statusLine)[0]
+	size, err = strconv.ParseInt(sizeStr, 10, 64)
+	if err != nil {
+		return 0, 0, 0, fmt.Errorf("unexpected statusLine %s: %s", statusLine, err)
 	}
 
-	size, err = strconv.ParseInt(matches[1], 10, 64)
-	if err != nil {
-		return 0, 0, 0, fmt.Errorf("unexpected statusline %s: %s", statusline, err)
+	if strings.Contains(deviceLine, "raid0") || strings.Contains(deviceLine, "linear") {
+		// In the device deviceLine, only disks have a number associated with them in [].
+		total = int64(strings.Count(deviceLine, "["))
+		return total, total, size, nil
+	}
+
+	if strings.Contains(deviceLine, "inactive") {
+		return 0, 0, size, nil
+	}
+
+	matches := statusLineRE.FindStringSubmatch(statusLine)
+	if len(matches) != 4 {
+		return 0, 0, 0, fmt.Errorf("couldn't find all the substring matches: %s", statusLine)
 	}
 
 	total, err = strconv.ParseInt(matches[2], 10, 64)
 	if err != nil {
-		return 0, 0, 0, fmt.Errorf("unexpected statusline %s: %s", statusline, err)
+		return 0, 0, 0, fmt.Errorf("unexpected statusLine %s: %s", statusLine, err)
 	}
 
 	active, err = strconv.ParseInt(matches[3], 10, 64)
 	if err != nil {
-		return 0, 0, 0, fmt.Errorf("unexpected statusline %s: %s", statusline, err)
+		return 0, 0, 0, fmt.Errorf("unexpected statusLine %s: %s", statusLine, err)
 	}
 
 	return active, total, size, nil
 }
 
-func evalBuildline(buildline string) (syncedBlocks int64, err error) {
-	matches := buildlineRE.FindStringSubmatch(buildline)
+func evalRecoveryLine(recoveryLine string) (syncedBlocks int64, err error) {
+	matches := recoveryLineRE.FindStringSubmatch(recoveryLine)
 	if len(matches) != 2 {
-		return 0, fmt.Errorf("unexpected buildline: %s", buildline)
+		return 0, fmt.Errorf("unexpected recoveryLine: %s", recoveryLine)
 	}
 
 	syncedBlocks, err = strconv.ParseInt(matches[1], 10, 64)
 	if err != nil {
-		return 0, fmt.Errorf("%s in buildline: %s", err, buildline)
+		return 0, fmt.Errorf("%s in recoveryLine: %s", err, recoveryLine)
 	}
 
 	return syncedBlocks, nil

vendor/github.com/prometheus/procfs/meminfo.go

@@ -0,0 +1,277 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// Meminfo represents memory statistics.
+type Meminfo struct {
+	// Total usable ram (i.e. physical ram minus a few reserved
+	// bits and the kernel binary code)
+	MemTotal uint64
+	// The sum of LowFree+HighFree
+	MemFree uint64
+	// An estimate of how much memory is available for starting
+	// new applications, without swapping. Calculated from
+	// MemFree, SReclaimable, the size of the file LRU lists, and
+	// the low watermarks in each zone.  The estimate takes into
+	// account that the system needs some page cache to function
+	// well, and that not all reclaimable slab will be
+	// reclaimable, due to items being in use. The impact of those
+	// factors will vary from system to system.
+	MemAvailable uint64
+	// Relatively temporary storage for raw disk blocks shouldn't
+	// get tremendously large (20MB or so)
+	Buffers uint64
+	Cached  uint64
+	// Memory that once was swapped out, is swapped back in but
+	// still also is in the swapfile (if memory is needed it
+	// doesn't need to be swapped out AGAIN because it is already
+	// in the swapfile. This saves I/O)
+	SwapCached uint64
+	// Memory that has been used more recently and usually not
+	// reclaimed unless absolutely necessary.
+	Active uint64
+	// Memory which has been less recently used.  It is more
+	// eligible to be reclaimed for other purposes
+	Inactive     uint64
+	ActiveAnon   uint64
+	InactiveAnon uint64
+	ActiveFile   uint64
+	InactiveFile uint64
+	Unevictable  uint64
+	Mlocked      uint64
+	// total amount of swap space available
+	SwapTotal uint64
+	// Memory which has been evicted from RAM, and is temporarily
+	// on the disk
+	SwapFree uint64
+	// Memory which is waiting to get written back to the disk
+	Dirty uint64
+	// Memory which is actively being written back to the disk
+	Writeback uint64
+	// Non-file backed pages mapped into userspace page tables
+	AnonPages uint64
+	// files which have been mapped, such as libraries
+	Mapped uint64
+	Shmem  uint64
+	// in-kernel data structures cache
+	Slab uint64
+	// Part of Slab, that might be reclaimed, such as caches
+	SReclaimable uint64
+	// Part of Slab, that cannot be reclaimed on memory pressure
+	SUnreclaim  uint64
+	KernelStack uint64
+	// amount of memory dedicated to the lowest level of page
+	// tables.
+	PageTables uint64
+	// NFS pages sent to the server, but not yet committed to
+	// stable storage
+	NFSUnstable uint64
+	// Memory used for block device "bounce buffers"
+	Bounce uint64
+	// Memory used by FUSE for temporary writeback buffers
+	WritebackTmp uint64
+	// Based on the overcommit ratio ('vm.overcommit_ratio'),
+	// this is the total amount of  memory currently available to
+	// be allocated on the system. This limit is only adhered to
+	// if strict overcommit accounting is enabled (mode 2 in
+	// 'vm.overcommit_memory').
+	// The CommitLimit is calculated with the following formula:
+	// CommitLimit = ([total RAM pages] - [total huge TLB pages]) *
+	//                overcommit_ratio / 100 + [total swap pages]
+	// For example, on a system with 1G of physical RAM and 7G
+	// of swap with a `vm.overcommit_ratio` of 30 it would
+	// yield a CommitLimit of 7.3G.
+	// For more details, see the memory overcommit documentation
+	// in vm/overcommit-accounting.
+	CommitLimit uint64
+	// The amount of memory presently allocated on the system.
+	// The committed memory is a sum of all of the memory which
+	// has been allocated by processes, even if it has not been
+	// "used" by them as of yet. A process which malloc()'s 1G
+	// of memory, but only touches 300M of it will show up as
+	// using 1G. This 1G is memory which has been "committed" to
+	// by the VM and can be used at any time by the allocating
+	// application. With strict overcommit enabled on the system
+	// (mode 2 in 'vm.overcommit_memory'),allocations which would
+	// exceed the CommitLimit (detailed above) will not be permitted.
+	// This is useful if one needs to guarantee that processes will
+	// not fail due to lack of memory once that memory has been
+	// successfully allocated.
+	CommittedAS uint64
+	// total size of vmalloc memory area
+	VmallocTotal uint64
+	// amount of vmalloc area which is used
+	VmallocUsed uint64
+	// largest contiguous block of vmalloc area which is free
+	VmallocChunk      uint64
+	HardwareCorrupted uint64
+	AnonHugePages     uint64
+	ShmemHugePages    uint64
+	ShmemPmdMapped    uint64
+	CmaTotal          uint64
+	CmaFree           uint64
+	HugePagesTotal    uint64
+	HugePagesFree     uint64
+	HugePagesRsvd     uint64
+	HugePagesSurp     uint64
+	Hugepagesize      uint64
+	DirectMap4k       uint64
+	DirectMap2M       uint64
+	DirectMap1G       uint64
+}
+
+// Meminfo returns an information about current kernel/system memory statistics.
+// See https://www.kernel.org/doc/Documentation/filesystems/proc.txt
+func (fs FS) Meminfo() (Meminfo, error) {
+	b, err := util.ReadFileNoStat(fs.proc.Path("meminfo"))
+	if err != nil {
+		return Meminfo{}, err
+	}
+
+	m, err := parseMemInfo(bytes.NewReader(b))
+	if err != nil {
+		return Meminfo{}, fmt.Errorf("failed to parse meminfo: %v", err)
+	}
+
+	return *m, nil
+}
+
+func parseMemInfo(r io.Reader) (*Meminfo, error) {
+	var m Meminfo
+	s := bufio.NewScanner(r)
+	for s.Scan() {
+		// Each line has at least a name and value; we ignore the unit.
+		fields := strings.Fields(s.Text())
+		if len(fields) < 2 {
+			return nil, fmt.Errorf("malformed meminfo line: %q", s.Text())
+		}
+
+		v, err := strconv.ParseUint(fields[1], 0, 64)
+		if err != nil {
+			return nil, err
+		}
+
+		switch fields[0] {
+		case "MemTotal:":
+			m.MemTotal = v
+		case "MemFree:":
+			m.MemFree = v
+		case "MemAvailable:":
+			m.MemAvailable = v
+		case "Buffers:":
+			m.Buffers = v
+		case "Cached:":
+			m.Cached = v
+		case "SwapCached:":
+			m.SwapCached = v
+		case "Active:":
+			m.Active = v
+		case "Inactive:":
+			m.Inactive = v
+		case "Active(anon):":
+			m.ActiveAnon = v
+		case "Inactive(anon):":
+			m.InactiveAnon = v
+		case "Active(file):":
+			m.ActiveFile = v
+		case "Inactive(file):":
+			m.InactiveFile = v
+		case "Unevictable:":
+			m.Unevictable = v
+		case "Mlocked:":
+			m.Mlocked = v
+		case "SwapTotal:":
+			m.SwapTotal = v
+		case "SwapFree:":
+			m.SwapFree = v
+		case "Dirty:":
+			m.Dirty = v
+		case "Writeback:":
+			m.Writeback = v
+		case "AnonPages:":
+			m.AnonPages = v
+		case "Mapped:":
+			m.Mapped = v
+		case "Shmem:":
+			m.Shmem = v
+		case "Slab:":
+			m.Slab = v
+		case "SReclaimable:":
+			m.SReclaimable = v
+		case "SUnreclaim:":
+			m.SUnreclaim = v
+		case "KernelStack:":
+			m.KernelStack = v
+		case "PageTables:":
+			m.PageTables = v
+		case "NFS_Unstable:":
+			m.NFSUnstable = v
+		case "Bounce:":
+			m.Bounce = v
+		case "WritebackTmp:":
+			m.WritebackTmp = v
+		case "CommitLimit:":
+			m.CommitLimit = v
+		case "Committed_AS:":
+			m.CommittedAS = v
+		case "VmallocTotal:":
+			m.VmallocTotal = v
+		case "VmallocUsed:":
+			m.VmallocUsed = v
+		case "VmallocChunk:":
+			m.VmallocChunk = v
+		case "HardwareCorrupted:":
+			m.HardwareCorrupted = v
+		case "AnonHugePages:":
+			m.AnonHugePages = v
+		case "ShmemHugePages:":
+			m.ShmemHugePages = v
+		case "ShmemPmdMapped:":
+			m.ShmemPmdMapped = v
+		case "CmaTotal:":
+			m.CmaTotal = v
+		case "CmaFree:":
+			m.CmaFree = v
+		case "HugePages_Total:":
+			m.HugePagesTotal = v
+		case "HugePages_Free:":
+			m.HugePagesFree = v
+		case "HugePages_Rsvd:":
+			m.HugePagesRsvd = v
+		case "HugePages_Surp:":
+			m.HugePagesSurp = v
+		case "Hugepagesize:":
+			m.Hugepagesize = v
+		case "DirectMap4k:":
+			m.DirectMap4k = v
+		case "DirectMap2M:":
+			m.DirectMap2M = v
+		case "DirectMap1G:":
+			m.DirectMap1G = v
+		}
+	}
+
+	return &m, nil
+}

vendor/github.com/prometheus/procfs/mountinfo.go

@@ -0,0 +1,180 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// A MountInfo is a type that describes the details, options
+// for each mount, parsed from /proc/self/mountinfo.
+// The fields described in each entry of /proc/self/mountinfo
+// is described in the following man page.
+// http://man7.org/linux/man-pages/man5/proc.5.html
+type MountInfo struct {
+	// Unique ID for the mount
+	MountID int
+	// The ID of the parent mount
+	ParentID int
+	// The value of `st_dev` for the files on this FS
+	MajorMinorVer string
+	// The pathname of the directory in the FS that forms
+	// the root for this mount
+	Root string
+	// The pathname of the mount point relative to the root
+	MountPoint string
+	// Mount options
+	Options map[string]string
+	// Zero or more optional fields
+	OptionalFields map[string]string
+	// The Filesystem type
+	FSType string
+	// FS specific information or "none"
+	Source string
+	// Superblock options
+	SuperOptions map[string]string
+}
+
+// Reads each line of the mountinfo file, and returns a list of formatted MountInfo structs.
+func parseMountInfo(info []byte) ([]*MountInfo, error) {
+	mounts := []*MountInfo{}
+	scanner := bufio.NewScanner(bytes.NewReader(info))
+	for scanner.Scan() {
+		mountString := scanner.Text()
+		parsedMounts, err := parseMountInfoString(mountString)
+		if err != nil {
+			return nil, err
+		}
+		mounts = append(mounts, parsedMounts)
+	}
+
+	err := scanner.Err()
+	return mounts, err
+}
+
+// Parses a mountinfo file line, and converts it to a MountInfo struct.
+// An important check here is to see if the hyphen separator, as if it does not exist,
+// it means that the line is malformed.
+func parseMountInfoString(mountString string) (*MountInfo, error) {
+	var err error
+
+	mountInfo := strings.Split(mountString, " ")
+	mountInfoLength := len(mountInfo)
+	if mountInfoLength < 11 {
+		return nil, fmt.Errorf("couldn't find enough fields in mount string: %s", mountString)
+	}
+
+	if mountInfo[mountInfoLength-4] != "-" {
+		return nil, fmt.Errorf("couldn't find separator in expected field: %s", mountInfo[mountInfoLength-4])
+	}
+
+	mount := &MountInfo{
+		MajorMinorVer:  mountInfo[2],
+		Root:           mountInfo[3],
+		MountPoint:     mountInfo[4],
+		Options:        mountOptionsParser(mountInfo[5]),
+		OptionalFields: nil,
+		FSType:         mountInfo[mountInfoLength-3],
+		Source:         mountInfo[mountInfoLength-2],
+		SuperOptions:   mountOptionsParser(mountInfo[mountInfoLength-1]),
+	}
+
+	mount.MountID, err = strconv.Atoi(mountInfo[0])
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse mount ID")
+	}
+	mount.ParentID, err = strconv.Atoi(mountInfo[1])
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse parent ID")
+	}
+	// Has optional fields, which is a space separated list of values.
+	// Example: shared:2 master:7
+	if mountInfo[6] != "" {
+		mount.OptionalFields, err = mountOptionsParseOptionalFields(mountInfo[6 : mountInfoLength-4])
+		if err != nil {
+			return nil, err
+		}
+	}
+	return mount, nil
+}
+
+// mountOptionsIsValidField checks a string against a valid list of optional fields keys.
+func mountOptionsIsValidField(s string) bool {
+	switch s {
+	case
+		"shared",
+		"master",
+		"propagate_from",
+		"unbindable":
+		return true
+	}
+	return false
+}
+
+// mountOptionsParseOptionalFields parses a list of optional fields strings into a double map of strings.
+func mountOptionsParseOptionalFields(o []string) (map[string]string, error) {
+	optionalFields := make(map[string]string)
+	for _, field := range o {
+		optionSplit := strings.SplitN(field, ":", 2)
+		value := ""
+		if len(optionSplit) == 2 {
+			value = optionSplit[1]
+		}
+		if mountOptionsIsValidField(optionSplit[0]) {
+			optionalFields[optionSplit[0]] = value
+		}
+	}
+	return optionalFields, nil
+}
+
+// Parses the mount options, superblock options.
+func mountOptionsParser(mountOptions string) map[string]string {
+	opts := make(map[string]string)
+	options := strings.Split(mountOptions, ",")
+	for _, opt := range options {
+		splitOption := strings.Split(opt, "=")
+		if len(splitOption) < 2 {
+			key := splitOption[0]
+			opts[key] = ""
+		} else {
+			key, value := splitOption[0], splitOption[1]
+			opts[key] = value
+		}
+	}
+	return opts
+}
+
+// Retrieves mountinfo information from `/proc/self/mountinfo`.
+func GetMounts() ([]*MountInfo, error) {
+	data, err := util.ReadFileNoStat("/proc/self/mountinfo")
+	if err != nil {
+		return nil, err
+	}
+	return parseMountInfo(data)
+}
+
+// Retrieves mountinfo information from a processes' `/proc/<pid>/mountinfo`.
+func GetProcMounts(pid int) ([]*MountInfo, error) {
+	data, err := util.ReadFileNoStat(fmt.Sprintf("/proc/%d/mountinfo", pid))
+	if err != nil {
+		return nil, err
+	}
+	return parseMountInfo(data)
+}

vendor/github.com/prometheus/procfs/mountstats.go

@@ -39,8 +39,11 @@ const (
 	statVersion10 = "1.0"
 	statVersion11 = "1.1"
 
-	fieldTransport10Len = 10
-	fieldTransport11Len = 13
+	fieldTransport10TCPLen = 10
+	fieldTransport10UDPLen = 7
+
+	fieldTransport11TCPLen = 13
+	fieldTransport11UDPLen = 10
 )
 
 // A Mount is a device mount parsed from /proc/[pid]/mountstats.
@@ -66,6 +69,8 @@ type MountStats interface {
 type MountStatsNFS struct {
 	// The version of statistics provided.
 	StatVersion string
+	// The mount options of the NFS mount.
+	Opts map[string]string
 	// The age of the NFS mount.
 	Age time.Duration
 	// Statistics related to byte counters for various operations.
@@ -176,16 +181,18 @@ type NFSOperationStats struct {
 	// Number of bytes received for this operation, including RPC headers and payload.
 	BytesReceived uint64
 	// Duration all requests spent queued for transmission before they were sent.
-	CumulativeQueueTime time.Duration
+	CumulativeQueueMilliseconds uint64
 	// Duration it took to get a reply back after the request was transmitted.
-	CumulativeTotalResponseTime time.Duration
+	CumulativeTotalResponseMilliseconds uint64
 	// Duration from when a request was enqueued to when it was completely handled.
-	CumulativeTotalRequestTime time.Duration
+	CumulativeTotalRequestMilliseconds uint64
 }
 
 // A NFSTransportStats contains statistics for the NFS mount RPC requests and
 // responses.
 type NFSTransportStats struct {
+	// The transport protocol used for the NFS mount.
+	Protocol string
 	// The local port used for the NFS mount.
 	Port uint64
 	// Number of times the client has had to establish a connection from scratch
@@ -197,7 +204,7 @@ type NFSTransportStats struct {
 	// spent waiting for connections to the server to be established.
 	ConnectIdleTime uint64
 	// Duration since the NFS mount last saw any RPC traffic.
-	IdleTime time.Duration
+	IdleTimeSeconds uint64
 	// Number of RPC requests for this mount sent to the NFS server.
 	Sends uint64
 	// Number of RPC responses for this mount received from the NFS server.
@@ -312,6 +319,7 @@ func parseMount(ss []string) (*Mount, error) {
 func parseMountStatsNFS(s *bufio.Scanner, statVersion string) (*MountStatsNFS, error) {
 	// Field indicators for parsing specific types of data
 	const (
+		fieldOpts       = "opts:"
 		fieldAge        = "age:"
 		fieldBytes      = "bytes:"
 		fieldEvents     = "events:"
@@ -333,6 +341,18 @@ func parseMountStatsNFS(s *bufio.Scanner, statVersion string) (*MountStatsNFS, e
 		}
 
 		switch ss[0] {
+		case fieldOpts:
+			if stats.Opts == nil {
+				stats.Opts = map[string]string{}
+			}
+			for _, opt := range strings.Split(ss[1], ",") {
+				split := strings.Split(opt, "=")
+				if len(split) == 2 {
+					stats.Opts[split[0]] = split[1]
+				} else {
+					stats.Opts[opt] = ""
+				}
+			}
 		case fieldAge:
 			// Age integer is in seconds
 			d, err := time.ParseDuration(ss[1] + "s")
@@ -360,7 +380,7 @@ func parseMountStatsNFS(s *bufio.Scanner, statVersion string) (*MountStatsNFS, e
 				return nil, fmt.Errorf("not enough information for NFS transport stats: %v", ss)
 			}
 
-			tstats, err := parseNFSTransportStats(ss[2:], statVersion)
+			tstats, err := parseNFSTransportStats(ss[1:], statVersion)
 			if err != nil {
 				return nil, err
 			}
@@ -504,15 +524,15 @@ func parseNFSOperationStats(s *bufio.Scanner) ([]NFSOperationStats, error) {
 		}
 
 		ops = append(ops, NFSOperationStats{
-			Operation:                   strings.TrimSuffix(ss[0], ":"),
-			Requests:                    ns[0],
-			Transmissions:               ns[1],
-			MajorTimeouts:               ns[2],
-			BytesSent:                   ns[3],
-			BytesReceived:               ns[4],
-			CumulativeQueueTime:         time.Duration(ns[5]) * time.Millisecond,
-			CumulativeTotalResponseTime: time.Duration(ns[6]) * time.Millisecond,
-			CumulativeTotalRequestTime:  time.Duration(ns[7]) * time.Millisecond,
+			Operation:                           strings.TrimSuffix(ss[0], ":"),
+			Requests:                            ns[0],
+			Transmissions:                       ns[1],
+			MajorTimeouts:                       ns[2],
+			BytesSent:                           ns[3],
+			BytesReceived:                       ns[4],
+			CumulativeQueueMilliseconds:         ns[5],
+			CumulativeTotalResponseMilliseconds: ns[6],
+			CumulativeTotalRequestMilliseconds:  ns[7],
 		})
 	}
 
@@ -522,13 +542,33 @@ func parseNFSOperationStats(s *bufio.Scanner) ([]NFSOperationStats, error) {
 // parseNFSTransportStats parses a NFSTransportStats line using an input set of
 // integer fields matched to a specific stats version.
 func parseNFSTransportStats(ss []string, statVersion string) (*NFSTransportStats, error) {
+	// Extract the protocol field. It is the only string value in the line
+	protocol := ss[0]
+	ss = ss[1:]
+
 	switch statVersion {
 	case statVersion10:
-		if len(ss) != fieldTransport10Len {
+		var expectedLength int
+		if protocol == "tcp" {
+			expectedLength = fieldTransport10TCPLen
+		} else if protocol == "udp" {
+			expectedLength = fieldTransport10UDPLen
+		} else {
+			return nil, fmt.Errorf("invalid NFS protocol \"%s\" in stats 1.0 statement: %v", protocol, ss)
+		}
+		if len(ss) != expectedLength {
 			return nil, fmt.Errorf("invalid NFS transport stats 1.0 statement: %v", ss)
 		}
 	case statVersion11:
-		if len(ss) != fieldTransport11Len {
+		var expectedLength int
+		if protocol == "tcp" {
+			expectedLength = fieldTransport11TCPLen
+		} else if protocol == "udp" {
+			expectedLength = fieldTransport11UDPLen
+		} else {
+			return nil, fmt.Errorf("invalid NFS protocol \"%s\" in stats 1.1 statement: %v", protocol, ss)
+		}
+		if len(ss) != expectedLength {
 			return nil, fmt.Errorf("invalid NFS transport stats 1.1 statement: %v", ss)
 		}
 	default:
@@ -536,12 +576,13 @@ func parseNFSTransportStats(ss []string, statVersion string) (*NFSTransportStats
 	}
 
 	// Allocate enough for v1.1 stats since zero value for v1.1 stats will be okay
-	// in a v1.0 response.
+	// in a v1.0 response. Since the stat length is bigger for TCP stats, we use
+	// the TCP length here.
 	//
 	// Note: slice length must be set to length of v1.1 stats to avoid a panic when
 	// only v1.0 stats are present.
 	// See: https://github.com/prometheus/node_exporter/issues/571.
-	ns := make([]uint64, fieldTransport11Len)
+	ns := make([]uint64, fieldTransport11TCPLen)
 	for i, s := range ss {
 		n, err := strconv.ParseUint(s, 10, 64)
 		if err != nil {
@@ -551,12 +592,23 @@ func parseNFSTransportStats(ss []string, statVersion string) (*NFSTransportStats
 		ns[i] = n
 	}
 
+	// The fields differ depending on the transport protocol (TCP or UDP)
+	// From https://utcc.utoronto.ca/%7Ecks/space/blog/linux/NFSMountstatsXprt
+	//
+	// For the udp RPC transport there is no connection count, connect idle time,
+	// or idle time (fields #3, #4, and #5); all other fields are the same. So
+	// we set them to 0 here.
+	if protocol == "udp" {
+		ns = append(ns[:2], append(make([]uint64, 3), ns[2:]...)...)
+	}
+
 	return &NFSTransportStats{
+		Protocol:                 protocol,
 		Port:                     ns[0],
 		Bind:                     ns[1],
 		Connect:                  ns[2],
 		ConnectIdleTime:          ns[3],
-		IdleTime:                 time.Duration(ns[4]) * time.Second,
+		IdleTimeSeconds:          ns[4],
 		Sends:                    ns[5],
 		Receives:                 ns[6],
 		BadTransactionIDs:        ns[7],

vendor/github.com/prometheus/procfs/net_conntrackstat.go

@@ -0,0 +1,153 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// A ConntrackStatEntry represents one line from net/stat/nf_conntrack
+// and contains netfilter conntrack statistics at one CPU core
+type ConntrackStatEntry struct {
+	Entries       uint64
+	Found         uint64
+	Invalid       uint64
+	Ignore        uint64
+	Insert        uint64
+	InsertFailed  uint64
+	Drop          uint64
+	EarlyDrop     uint64
+	SearchRestart uint64
+}
+
+// Retrieves netfilter's conntrack statistics, split by CPU cores
+func (fs FS) ConntrackStat() ([]ConntrackStatEntry, error) {
+	return readConntrackStat(fs.proc.Path("net", "stat", "nf_conntrack"))
+}
+
+// Parses a slice of ConntrackStatEntries from the given filepath
+func readConntrackStat(path string) ([]ConntrackStatEntry, error) {
+	// This file is small and can be read with one syscall.
+	b, err := util.ReadFileNoStat(path)
+	if err != nil {
+		// Do not wrap this error so the caller can detect os.IsNotExist and
+		// similar conditions.
+		return nil, err
+	}
+
+	stat, err := parseConntrackStat(bytes.NewReader(b))
+	if err != nil {
+		return nil, fmt.Errorf("failed to read conntrack stats from %q: %v", path, err)
+	}
+
+	return stat, nil
+}
+
+// Reads the contents of a conntrack statistics file and parses a slice of ConntrackStatEntries
+func parseConntrackStat(r io.Reader) ([]ConntrackStatEntry, error) {
+	var entries []ConntrackStatEntry
+
+	scanner := bufio.NewScanner(r)
+	scanner.Scan()
+	for scanner.Scan() {
+		fields := strings.Fields(scanner.Text())
+		conntrackEntry, err := parseConntrackStatEntry(fields)
+		if err != nil {
+			return nil, err
+		}
+		entries = append(entries, *conntrackEntry)
+	}
+
+	return entries, nil
+}
+
+// Parses a ConntrackStatEntry from given array of fields
+func parseConntrackStatEntry(fields []string) (*ConntrackStatEntry, error) {
+	if len(fields) != 17 {
+		return nil, fmt.Errorf("invalid conntrackstat entry, missing fields")
+	}
+	entry := &ConntrackStatEntry{}
+
+	entries, err := parseConntrackStatField(fields[0])
+	if err != nil {
+		return nil, err
+	}
+	entry.Entries = entries
+
+	found, err := parseConntrackStatField(fields[2])
+	if err != nil {
+		return nil, err
+	}
+	entry.Found = found
+
+	invalid, err := parseConntrackStatField(fields[4])
+	if err != nil {
+		return nil, err
+	}
+	entry.Invalid = invalid
+
+	ignore, err := parseConntrackStatField(fields[5])
+	if err != nil {
+		return nil, err
+	}
+	entry.Ignore = ignore
+
+	insert, err := parseConntrackStatField(fields[8])
+	if err != nil {
+		return nil, err
+	}
+	entry.Insert = insert
+
+	insertFailed, err := parseConntrackStatField(fields[9])
+	if err != nil {
+		return nil, err
+	}
+	entry.InsertFailed = insertFailed
+
+	drop, err := parseConntrackStatField(fields[10])
+	if err != nil {
+		return nil, err
+	}
+	entry.Drop = drop
+
+	earlyDrop, err := parseConntrackStatField(fields[11])
+	if err != nil {
+		return nil, err
+	}
+	entry.EarlyDrop = earlyDrop
+
+	searchRestart, err := parseConntrackStatField(fields[16])
+	if err != nil {
+		return nil, err
+	}
+	entry.SearchRestart = searchRestart
+
+	return entry, nil
+}
+
+// Parses a uint64 from given hex in string
+func parseConntrackStatField(field string) (uint64, error) {
+	val, err := strconv.ParseUint(field, 16, 64)
+	if err != nil {
+		return 0, fmt.Errorf("couldn't parse \"%s\" field: %s", field, err)
+	}
+	return val, err
+}

vendor/github.com/prometheus/procfs/net_dev.go

@@ -47,23 +47,13 @@ type NetDevLine struct {
 // are interface names.
 type NetDev map[string]NetDevLine
 
-// NewNetDev returns kernel/system statistics read from /proc/net/dev.
-func NewNetDev() (NetDev, error) {
-	fs, err := NewFS(DefaultMountPoint)
-	if err != nil {
-		return nil, err
-	}
-
-	return fs.NewNetDev()
+// NetDev returns kernel/system statistics read from /proc/net/dev.
+func (fs FS) NetDev() (NetDev, error) {
+	return newNetDev(fs.proc.Path("net/dev"))
 }
 
-// NewNetDev returns kernel/system statistics read from /proc/net/dev.
-func (fs FS) NewNetDev() (NetDev, error) {
-	return newNetDev(fs.Path("net/dev"))
-}
-
-// NewNetDev returns kernel/system statistics read from /proc/[pid]/net/dev.
-func (p Proc) NewNetDev() (NetDev, error) {
+// NetDev returns kernel/system statistics read from /proc/[pid]/net/dev.
+func (p Proc) NetDev() (NetDev, error) {
 	return newNetDev(p.path("net/dev"))
 }
 
@@ -75,7 +65,7 @@ func newNetDev(file string) (NetDev, error) {
 	}
 	defer f.Close()
 
-	nd := NetDev{}
+	netDev := NetDev{}
 	s := bufio.NewScanner(f)
 	for n := 0; s.Scan(); n++ {
 		// Skip the 2 header lines.
@@ -83,20 +73,20 @@ func newNetDev(file string) (NetDev, error) {
 			continue
 		}
 
-		line, err := nd.parseLine(s.Text())
+		line, err := netDev.parseLine(s.Text())
 		if err != nil {
-			return nd, err
+			return netDev, err
 		}
 
-		nd[line.Name] = *line
+		netDev[line.Name] = *line
 	}
 
-	return nd, s.Err()
+	return netDev, s.Err()
 }
 
 // parseLine parses a single line from the /proc/net/dev file. Header lines
 // must be filtered prior to calling this method.
-func (nd NetDev) parseLine(rawLine string) (*NetDevLine, error) {
+func (netDev NetDev) parseLine(rawLine string) (*NetDevLine, error) {
 	parts := strings.SplitN(rawLine, ":", 2)
 	if len(parts) != 2 {
 		return nil, errors.New("invalid net/dev line, missing colon")
@@ -185,15 +175,14 @@ func (nd NetDev) parseLine(rawLine string) (*NetDevLine, error) {
 
 // Total aggregates the values across interfaces and returns a new NetDevLine.
 // The Name field will be a sorted comma separated list of interface names.
-func (nd NetDev) Total() NetDevLine {
+func (netDev NetDev) Total() NetDevLine {
 	total := NetDevLine{}
 
-	names := make([]string, 0, len(nd))
-	for _, ifc := range nd {
+	names := make([]string, 0, len(netDev))
+	for _, ifc := range netDev {
 		names = append(names, ifc.Name)
 		total.RxBytes += ifc.RxBytes
 		total.RxPackets += ifc.RxPackets
-		total.RxPackets += ifc.RxPackets
 		total.RxErrors += ifc.RxErrors
 		total.RxDropped += ifc.RxDropped
 		total.RxFIFO += ifc.RxFIFO

vendor/github.com/prometheus/procfs/net_sockstat.go

@@ -0,0 +1,163 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// A NetSockstat contains the output of /proc/net/sockstat{,6} for IPv4 or IPv6,
+// respectively.
+type NetSockstat struct {
+	// Used is non-nil for IPv4 sockstat results, but nil for IPv6.
+	Used      *int
+	Protocols []NetSockstatProtocol
+}
+
+// A NetSockstatProtocol contains statistics about a given socket protocol.
+// Pointer fields indicate that the value may or may not be present on any
+// given protocol.
+type NetSockstatProtocol struct {
+	Protocol string
+	InUse    int
+	Orphan   *int
+	TW       *int
+	Alloc    *int
+	Mem      *int
+	Memory   *int
+}
+
+// NetSockstat retrieves IPv4 socket statistics.
+func (fs FS) NetSockstat() (*NetSockstat, error) {
+	return readSockstat(fs.proc.Path("net", "sockstat"))
+}
+
+// NetSockstat6 retrieves IPv6 socket statistics.
+//
+// If IPv6 is disabled on this kernel, the returned error can be checked with
+// os.IsNotExist.
+func (fs FS) NetSockstat6() (*NetSockstat, error) {
+	return readSockstat(fs.proc.Path("net", "sockstat6"))
+}
+
+// readSockstat opens and parses a NetSockstat from the input file.
+func readSockstat(name string) (*NetSockstat, error) {
+	// This file is small and can be read with one syscall.
+	b, err := util.ReadFileNoStat(name)
+	if err != nil {
+		// Do not wrap this error so the caller can detect os.IsNotExist and
+		// similar conditions.
+		return nil, err
+	}
+
+	stat, err := parseSockstat(bytes.NewReader(b))
+	if err != nil {
+		return nil, fmt.Errorf("failed to read sockstats from %q: %v", name, err)
+	}
+
+	return stat, nil
+}
+
+// parseSockstat reads the contents of a sockstat file and parses a NetSockstat.
+func parseSockstat(r io.Reader) (*NetSockstat, error) {
+	var stat NetSockstat
+	s := bufio.NewScanner(r)
+	for s.Scan() {
+		// Expect a minimum of a protocol and one key/value pair.
+		fields := strings.Split(s.Text(), " ")
+		if len(fields) < 3 {
+			return nil, fmt.Errorf("malformed sockstat line: %q", s.Text())
+		}
+
+		// The remaining fields are key/value pairs.
+		kvs, err := parseSockstatKVs(fields[1:])
+		if err != nil {
+			return nil, fmt.Errorf("error parsing sockstat key/value pairs from %q: %v", s.Text(), err)
+		}
+
+		// The first field is the protocol. We must trim its colon suffix.
+		proto := strings.TrimSuffix(fields[0], ":")
+		switch proto {
+		case "sockets":
+			// Special case: IPv4 has a sockets "used" key/value pair that we
+			// embed at the top level of the structure.
+			used := kvs["used"]
+			stat.Used = &used
+		default:
+			// Parse all other lines as individual protocols.
+			nsp := parseSockstatProtocol(kvs)
+			nsp.Protocol = proto
+			stat.Protocols = append(stat.Protocols, nsp)
+		}
+	}
+
+	if err := s.Err(); err != nil {
+		return nil, err
+	}
+
+	return &stat, nil
+}
+
+// parseSockstatKVs parses a string slice into a map of key/value pairs.
+func parseSockstatKVs(kvs []string) (map[string]int, error) {
+	if len(kvs)%2 != 0 {
+		return nil, errors.New("odd number of fields in key/value pairs")
+	}
+
+	// Iterate two values at a time to gather key/value pairs.
+	out := make(map[string]int, len(kvs)/2)
+	for i := 0; i < len(kvs); i += 2 {
+		vp := util.NewValueParser(kvs[i+1])
+		out[kvs[i]] = vp.Int()
+
+		if err := vp.Err(); err != nil {
+			return nil, err
+		}
+	}
+
+	return out, nil
+}
+
+// parseSockstatProtocol parses a NetSockstatProtocol from the input kvs map.
+func parseSockstatProtocol(kvs map[string]int) NetSockstatProtocol {
+	var nsp NetSockstatProtocol
+	for k, v := range kvs {
+		// Capture the range variable to ensure we get unique pointers for
+		// each of the optional fields.
+		v := v
+		switch k {
+		case "inuse":
+			nsp.InUse = v
+		case "orphan":
+			nsp.Orphan = &v
+		case "tw":
+			nsp.TW = &v
+		case "alloc":
+			nsp.Alloc = &v
+		case "mem":
+			nsp.Mem = &v
+		case "memory":
+			nsp.Memory = &v
+		}
+	}
+
+	return nsp
+}

vendor/github.com/prometheus/procfs/net_softnet.go

@@ -0,0 +1,102 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// For the proc file format details,
+// See:
+// * Linux 2.6.23 https://elixir.bootlin.com/linux/v2.6.23/source/net/core/dev.c#L2343
+// * Linux 4.17 https://elixir.bootlin.com/linux/v4.17/source/net/core/net-procfs.c#L162
+// and https://elixir.bootlin.com/linux/v4.17/source/include/linux/netdevice.h#L2810.
+
+// SoftnetStat contains a single row of data from /proc/net/softnet_stat
+type SoftnetStat struct {
+	// Number of processed packets
+	Processed uint32
+	// Number of dropped packets
+	Dropped uint32
+	// Number of times processing packets ran out of quota
+	TimeSqueezed uint32
+}
+
+var softNetProcFile = "net/softnet_stat"
+
+// NetSoftnetStat reads data from /proc/net/softnet_stat.
+func (fs FS) NetSoftnetStat() ([]SoftnetStat, error) {
+	b, err := util.ReadFileNoStat(fs.proc.Path(softNetProcFile))
+	if err != nil {
+		return nil, err
+	}
+
+	entries, err := parseSoftnet(bytes.NewReader(b))
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse /proc/net/softnet_stat: %v", err)
+	}
+
+	return entries, nil
+}
+
+func parseSoftnet(r io.Reader) ([]SoftnetStat, error) {
+	const minColumns = 9
+
+	s := bufio.NewScanner(r)
+
+	var stats []SoftnetStat
+	for s.Scan() {
+		columns := strings.Fields(s.Text())
+		width := len(columns)
+
+		if width < minColumns {
+			return nil, fmt.Errorf("%d columns were detected, but at least %d were expected", width, minColumns)
+		}
+
+		// We only parse the first three columns at the moment.
+		us, err := parseHexUint32s(columns[0:3])
+		if err != nil {
+			return nil, err
+		}
+
+		stats = append(stats, SoftnetStat{
+			Processed:    us[0],
+			Dropped:      us[1],
+			TimeSqueezed: us[2],
+		})
+	}
+
+	return stats, nil
+}
+
+func parseHexUint32s(ss []string) ([]uint32, error) {
+	us := make([]uint32, 0, len(ss))
+	for _, s := range ss {
+		u, err := strconv.ParseUint(s, 16, 32)
+		if err != nil {
+			return nil, err
+		}
+
+		us = append(us, uint32(u))
+	}
+
+	return us, nil
+}

vendor/github.com/prometheus/procfs/net_udp.go

@@ -0,0 +1,229 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+)
+
+const (
+	// readLimit is used by io.LimitReader while reading the content of the
+	// /proc/net/udp{,6} files. The number of lines inside such a file is dynamic
+	// as each line represents a single used socket.
+	// In theory, the number of available sockets is 65535 (2^16 - 1) per IP.
+	// With e.g. 150 Byte per line and the maximum number of 65535,
+	// the reader needs to handle 150 Byte * 65535 =~ 10 MB for a single IP.
+	readLimit = 4294967296 // Byte -> 4 GiB
+)
+
+type (
+	// NetUDP represents the contents of /proc/net/udp{,6} file without the header.
+	NetUDP []*netUDPLine
+
+	// NetUDPSummary provides already computed values like the total queue lengths or
+	// the total number of used sockets. In contrast to NetUDP it does not collect
+	// the parsed lines into a slice.
+	NetUDPSummary struct {
+		// TxQueueLength shows the total queue length of all parsed tx_queue lengths.
+		TxQueueLength uint64
+		// RxQueueLength shows the total queue length of all parsed rx_queue lengths.
+		RxQueueLength uint64
+		// UsedSockets shows the total number of parsed lines representing the
+		// number of used sockets.
+		UsedSockets uint64
+	}
+
+	// netUDPLine represents the fields parsed from a single line
+	// in /proc/net/udp{,6}. Fields which are not used by UDP are skipped.
+	// For the proc file format details, see https://linux.die.net/man/5/proc.
+	netUDPLine struct {
+		Sl        uint64
+		LocalAddr net.IP
+		LocalPort uint64
+		RemAddr   net.IP
+		RemPort   uint64
+		St        uint64
+		TxQueue   uint64
+		RxQueue   uint64
+		UID       uint64
+	}
+)
+
+// NetUDP returns the IPv4 kernel/networking statistics for UDP datagrams
+// read from /proc/net/udp.
+func (fs FS) NetUDP() (NetUDP, error) {
+	return newNetUDP(fs.proc.Path("net/udp"))
+}
+
+// NetUDP6 returns the IPv6 kernel/networking statistics for UDP datagrams
+// read from /proc/net/udp6.
+func (fs FS) NetUDP6() (NetUDP, error) {
+	return newNetUDP(fs.proc.Path("net/udp6"))
+}
+
+// NetUDPSummary returns already computed statistics like the total queue lengths
+// for UDP datagrams read from /proc/net/udp.
+func (fs FS) NetUDPSummary() (*NetUDPSummary, error) {
+	return newNetUDPSummary(fs.proc.Path("net/udp"))
+}
+
+// NetUDP6Summary returns already computed statistics like the total queue lengths
+// for UDP datagrams read from /proc/net/udp6.
+func (fs FS) NetUDP6Summary() (*NetUDPSummary, error) {
+	return newNetUDPSummary(fs.proc.Path("net/udp6"))
+}
+
+// newNetUDP creates a new NetUDP{,6} from the contents of the given file.
+func newNetUDP(file string) (NetUDP, error) {
+	f, err := os.Open(file)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	netUDP := NetUDP{}
+
+	lr := io.LimitReader(f, readLimit)
+	s := bufio.NewScanner(lr)
+	s.Scan() // skip first line with headers
+	for s.Scan() {
+		fields := strings.Fields(s.Text())
+		line, err := parseNetUDPLine(fields)
+		if err != nil {
+			return nil, err
+		}
+		netUDP = append(netUDP, line)
+	}
+	if err := s.Err(); err != nil {
+		return nil, err
+	}
+	return netUDP, nil
+}
+
+// newNetUDPSummary creates a new NetUDP{,6} from the contents of the given file.
+func newNetUDPSummary(file string) (*NetUDPSummary, error) {
+	f, err := os.Open(file)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	netUDPSummary := &NetUDPSummary{}
+
+	lr := io.LimitReader(f, readLimit)
+	s := bufio.NewScanner(lr)
+	s.Scan() // skip first line with headers
+	for s.Scan() {
+		fields := strings.Fields(s.Text())
+		line, err := parseNetUDPLine(fields)
+		if err != nil {
+			return nil, err
+		}
+		netUDPSummary.TxQueueLength += line.TxQueue
+		netUDPSummary.RxQueueLength += line.RxQueue
+		netUDPSummary.UsedSockets++
+	}
+	if err := s.Err(); err != nil {
+		return nil, err
+	}
+	return netUDPSummary, nil
+}
+
+// parseNetUDPLine parses a single line, represented by a list of fields.
+func parseNetUDPLine(fields []string) (*netUDPLine, error) {
+	line := &netUDPLine{}
+	if len(fields) < 8 {
+		return nil, fmt.Errorf(
+			"cannot parse net udp socket line as it has less then 8 columns: %s",
+			strings.Join(fields, " "),
+		)
+	}
+	var err error // parse error
+
+	// sl
+	s := strings.Split(fields[0], ":")
+	if len(s) != 2 {
+		return nil, fmt.Errorf(
+			"cannot parse sl field in udp socket line: %s", fields[0])
+	}
+
+	if line.Sl, err = strconv.ParseUint(s[0], 0, 64); err != nil {
+		return nil, fmt.Errorf("cannot parse sl value in udp socket line: %s", err)
+	}
+	// local_address
+	l := strings.Split(fields[1], ":")
+	if len(l) != 2 {
+		return nil, fmt.Errorf(
+			"cannot parse local_address field in udp socket line: %s", fields[1])
+	}
+	if line.LocalAddr, err = hex.DecodeString(l[0]); err != nil {
+		return nil, fmt.Errorf(
+			"cannot parse local_address value in udp socket line: %s", err)
+	}
+	if line.LocalPort, err = strconv.ParseUint(l[1], 16, 64); err != nil {
+		return nil, fmt.Errorf(
+			"cannot parse local_address port value in udp socket line: %s", err)
+	}
+
+	// remote_address
+	r := strings.Split(fields[2], ":")
+	if len(r) != 2 {
+		return nil, fmt.Errorf(
+			"cannot parse rem_address field in udp socket line: %s", fields[1])
+	}
+	if line.RemAddr, err = hex.DecodeString(r[0]); err != nil {
+		return nil, fmt.Errorf(
+			"cannot parse rem_address value in udp socket line: %s", err)
+	}
+	if line.RemPort, err = strconv.ParseUint(r[1], 16, 64); err != nil {
+		return nil, fmt.Errorf(
+			"cannot parse rem_address port value in udp socket line: %s", err)
+	}
+
+	// st
+	if line.St, err = strconv.ParseUint(fields[3], 16, 64); err != nil {
+		return nil, fmt.Errorf(
+			"cannot parse st value in udp socket line: %s", err)
+	}
+
+	// tx_queue and rx_queue
+	q := strings.Split(fields[4], ":")
+	if len(q) != 2 {
+		return nil, fmt.Errorf(
+			"cannot parse tx/rx queues in udp socket line as it has a missing colon: %s",
+			fields[4],
+		)
+	}
+	if line.TxQueue, err = strconv.ParseUint(q[0], 16, 64); err != nil {
+		return nil, fmt.Errorf("cannot parse tx_queue value in udp socket line: %s", err)
+	}
+	if line.RxQueue, err = strconv.ParseUint(q[1], 16, 64); err != nil {
+		return nil, fmt.Errorf("cannot parse rx_queue value in udp socket line: %s", err)
+	}
+
+	// uid
+	if line.UID, err = strconv.ParseUint(fields[7], 0, 64); err != nil {
+		return nil, fmt.Errorf(
+			"cannot parse uid value in udp socket line: %s", err)
+	}
+
+	return line, nil
+}

vendor/github.com/prometheus/procfs/net_unix.go

@@ -0,0 +1,257 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// For the proc file format details,
+// see https://elixir.bootlin.com/linux/v4.17/source/net/unix/af_unix.c#L2815
+// and https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/net.h#L48.
+
+// Constants for the various /proc/net/unix enumerations.
+// TODO: match against x/sys/unix or similar?
+const (
+	netUnixTypeStream    = 1
+	netUnixTypeDgram     = 2
+	netUnixTypeSeqpacket = 5
+
+	netUnixFlagDefault = 0
+	netUnixFlagListen  = 1 << 16
+
+	netUnixStateUnconnected  = 1
+	netUnixStateConnecting   = 2
+	netUnixStateConnected    = 3
+	netUnixStateDisconnected = 4
+)
+
+// NetUNIXType is the type of the type field.
+type NetUNIXType uint64
+
+// NetUNIXFlags is the type of the flags field.
+type NetUNIXFlags uint64
+
+// NetUNIXState is the type of the state field.
+type NetUNIXState uint64
+
+// NetUNIXLine represents a line of /proc/net/unix.
+type NetUNIXLine struct {
+	KernelPtr string
+	RefCount  uint64
+	Protocol  uint64
+	Flags     NetUNIXFlags
+	Type      NetUNIXType
+	State     NetUNIXState
+	Inode     uint64
+	Path      string
+}
+
+// NetUNIX holds the data read from /proc/net/unix.
+type NetUNIX struct {
+	Rows []*NetUNIXLine
+}
+
+// NetUNIX returns data read from /proc/net/unix.
+func (fs FS) NetUNIX() (*NetUNIX, error) {
+	return readNetUNIX(fs.proc.Path("net/unix"))
+}
+
+// readNetUNIX reads data in /proc/net/unix format from the specified file.
+func readNetUNIX(file string) (*NetUNIX, error) {
+	// This file could be quite large and a streaming read is desirable versus
+	// reading the entire contents at once.
+	f, err := os.Open(file)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	return parseNetUNIX(f)
+}
+
+// parseNetUNIX creates a NetUnix structure from the incoming stream.
+func parseNetUNIX(r io.Reader) (*NetUNIX, error) {
+	// Begin scanning by checking for the existence of Inode.
+	s := bufio.NewScanner(r)
+	s.Scan()
+
+	// From the man page of proc(5), it does not contain an Inode field,
+	// but in actually it exists. This code works for both cases.
+	hasInode := strings.Contains(s.Text(), "Inode")
+
+	// Expect a minimum number of fields, but Inode and Path are optional:
+	// Num       RefCount Protocol Flags    Type St Inode Path
+	minFields := 6
+	if hasInode {
+		minFields++
+	}
+
+	var nu NetUNIX
+	for s.Scan() {
+		line := s.Text()
+		item, err := nu.parseLine(line, hasInode, minFields)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse /proc/net/unix data %q: %v", line, err)
+		}
+
+		nu.Rows = append(nu.Rows, item)
+	}
+
+	if err := s.Err(); err != nil {
+		return nil, fmt.Errorf("failed to scan /proc/net/unix data: %v", err)
+	}
+
+	return &nu, nil
+}
+
+func (u *NetUNIX) parseLine(line string, hasInode bool, min int) (*NetUNIXLine, error) {
+	fields := strings.Fields(line)
+
+	l := len(fields)
+	if l < min {
+		return nil, fmt.Errorf("expected at least %d fields but got %d", min, l)
+	}
+
+	// Field offsets are as follows:
+	// Num       RefCount Protocol Flags    Type St Inode Path
+
+	kernelPtr := strings.TrimSuffix(fields[0], ":")
+
+	users, err := u.parseUsers(fields[1])
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse ref count(%s): %v", fields[1], err)
+	}
+
+	flags, err := u.parseFlags(fields[3])
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse flags(%s): %v", fields[3], err)
+	}
+
+	typ, err := u.parseType(fields[4])
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse type(%s): %v", fields[4], err)
+	}
+
+	state, err := u.parseState(fields[5])
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse state(%s): %v", fields[5], err)
+	}
+
+	var inode uint64
+	if hasInode {
+		inode, err = u.parseInode(fields[6])
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse inode(%s): %v", fields[6], err)
+		}
+	}
+
+	n := &NetUNIXLine{
+		KernelPtr: kernelPtr,
+		RefCount:  users,
+		Type:      typ,
+		Flags:     flags,
+		State:     state,
+		Inode:     inode,
+	}
+
+	// Path field is optional.
+	if l > min {
+		// Path occurs at either index 6 or 7 depending on whether inode is
+		// already present.
+		pathIdx := 7
+		if !hasInode {
+			pathIdx--
+		}
+
+		n.Path = fields[pathIdx]
+	}
+
+	return n, nil
+}
+
+func (u NetUNIX) parseUsers(s string) (uint64, error) {
+	return strconv.ParseUint(s, 16, 32)
+}
+
+func (u NetUNIX) parseType(s string) (NetUNIXType, error) {
+	typ, err := strconv.ParseUint(s, 16, 16)
+	if err != nil {
+		return 0, err
+	}
+
+	return NetUNIXType(typ), nil
+}
+
+func (u NetUNIX) parseFlags(s string) (NetUNIXFlags, error) {
+	flags, err := strconv.ParseUint(s, 16, 32)
+	if err != nil {
+		return 0, err
+	}
+
+	return NetUNIXFlags(flags), nil
+}
+
+func (u NetUNIX) parseState(s string) (NetUNIXState, error) {
+	st, err := strconv.ParseInt(s, 16, 8)
+	if err != nil {
+		return 0, err
+	}
+
+	return NetUNIXState(st), nil
+}
+
+func (u NetUNIX) parseInode(s string) (uint64, error) {
+	return strconv.ParseUint(s, 10, 64)
+}
+
+func (t NetUNIXType) String() string {
+	switch t {
+	case netUnixTypeStream:
+		return "stream"
+	case netUnixTypeDgram:
+		return "dgram"
+	case netUnixTypeSeqpacket:
+		return "seqpacket"
+	}
+	return "unknown"
+}
+
+func (f NetUNIXFlags) String() string {
+	switch f {
+	case netUnixFlagListen:
+		return "listen"
+	default:
+		return "default"
+	}
+}
+
+func (s NetUNIXState) String() string {
+	switch s {
+	case netUnixStateUnconnected:
+		return "unconnected"
+	case netUnixStateConnecting:
+		return "connecting"
+	case netUnixStateConnected:
+		return "connected"
+	case netUnixStateDisconnected:
+		return "disconnected"
+	}
+	return "unknown"
+}

vendor/github.com/prometheus/procfs/nfs/nfs.go

@@ -1,263 +0,0 @@
-// Copyright 2018 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// Package nfs implements parsing of /proc/net/rpc/nfsd.
-// Fields are documented in https://www.svennd.be/nfsd-stats-explained-procnetrpcnfsd/
-package nfs
-
-// ReplyCache models the "rc" line.
-type ReplyCache struct {
-	Hits    uint64
-	Misses  uint64
-	NoCache uint64
-}
-
-// FileHandles models the "fh" line.
-type FileHandles struct {
-	Stale        uint64
-	TotalLookups uint64
-	AnonLookups  uint64
-	DirNoCache   uint64
-	NoDirNoCache uint64
-}
-
-// InputOutput models the "io" line.
-type InputOutput struct {
-	Read  uint64
-	Write uint64
-}
-
-// Threads models the "th" line.
-type Threads struct {
-	Threads uint64
-	FullCnt uint64
-}
-
-// ReadAheadCache models the "ra" line.
-type ReadAheadCache struct {
-	CacheSize      uint64
-	CacheHistogram []uint64
-	NotFound       uint64
-}
-
-// Network models the "net" line.
-type Network struct {
-	NetCount   uint64
-	UDPCount   uint64
-	TCPCount   uint64
-	TCPConnect uint64
-}
-
-// ClientRPC models the nfs "rpc" line.
-type ClientRPC struct {
-	RPCCount        uint64
-	Retransmissions uint64
-	AuthRefreshes   uint64
-}
-
-// ServerRPC models the nfsd "rpc" line.
-type ServerRPC struct {
-	RPCCount uint64
-	BadCnt   uint64
-	BadFmt   uint64
-	BadAuth  uint64
-	BadcInt  uint64
-}
-
-// V2Stats models the "proc2" line.
-type V2Stats struct {
-	Null     uint64
-	GetAttr  uint64
-	SetAttr  uint64
-	Root     uint64
-	Lookup   uint64
-	ReadLink uint64
-	Read     uint64
-	WrCache  uint64
-	Write    uint64
-	Create   uint64
-	Remove   uint64
-	Rename   uint64
-	Link     uint64
-	SymLink  uint64
-	MkDir    uint64
-	RmDir    uint64
-	ReadDir  uint64
-	FsStat   uint64
-}
-
-// V3Stats models the "proc3" line.
-type V3Stats struct {
-	Null        uint64
-	GetAttr     uint64
-	SetAttr     uint64
-	Lookup      uint64
-	Access      uint64
-	ReadLink    uint64
-	Read        uint64
-	Write       uint64
-	Create      uint64
-	MkDir       uint64
-	SymLink     uint64
-	MkNod       uint64
-	Remove      uint64
-	RmDir       uint64
-	Rename      uint64
-	Link        uint64
-	ReadDir     uint64
-	ReadDirPlus uint64
-	FsStat      uint64
-	FsInfo      uint64
-	PathConf    uint64
-	Commit      uint64
-}
-
-// ClientV4Stats models the nfs "proc4" line.
-type ClientV4Stats struct {
-	Null               uint64
-	Read               uint64
-	Write              uint64
-	Commit             uint64
-	Open               uint64
-	OpenConfirm        uint64
-	OpenNoattr         uint64
-	OpenDowngrade      uint64
-	Close              uint64
-	Setattr            uint64
-	FsInfo             uint64
-	Renew              uint64
-	SetClientID        uint64
-	SetClientIDConfirm uint64
-	Lock               uint64
-	Lockt              uint64
-	Locku              uint64
-	Access             uint64
-	Getattr            uint64
-	Lookup             uint64
-	LookupRoot         uint64
-	Remove             uint64
-	Rename             uint64
-	Link               uint64
-	Symlink            uint64
-	Create             uint64
-	Pathconf           uint64
-	StatFs             uint64
-	ReadLink           uint64
-	ReadDir            uint64
-	ServerCaps         uint64
-	DelegReturn        uint64
-	GetACL             uint64
-	SetACL             uint64
-	FsLocations        uint64
-	ReleaseLockowner   uint64
-	Secinfo            uint64
-	FsidPresent        uint64
-	ExchangeID         uint64
-	CreateSession      uint64
-	DestroySession     uint64
-	Sequence           uint64
-	GetLeaseTime       uint64
-	ReclaimComplete    uint64
-	LayoutGet          uint64
-	GetDeviceInfo      uint64
-	LayoutCommit       uint64
-	LayoutReturn       uint64
-	SecinfoNoName      uint64
-	TestStateID        uint64
-	FreeStateID        uint64
-	GetDeviceList      uint64
-	BindConnToSession  uint64
-	DestroyClientID    uint64
-	Seek               uint64
-	Allocate           uint64
-	DeAllocate         uint64
-	LayoutStats        uint64
-	Clone              uint64
-}
-
-// ServerV4Stats models the nfsd "proc4" line.
-type ServerV4Stats struct {
-	Null     uint64
-	Compound uint64
-}
-
-// V4Ops models the "proc4ops" line: NFSv4 operations
-// Variable list, see:
-// v4.0 https://tools.ietf.org/html/rfc3010 (38 operations)
-// v4.1 https://tools.ietf.org/html/rfc5661 (58 operations)
-// v4.2 https://tools.ietf.org/html/draft-ietf-nfsv4-minorversion2-41 (71 operations)
-type V4Ops struct {
-	//Values       uint64 // Variable depending on v4.x sub-version. TODO: Will this always at least include the fields in this struct?
-	Op0Unused    uint64
-	Op1Unused    uint64
-	Op2Future    uint64
-	Access       uint64
-	Close        uint64
-	Commit       uint64
-	Create       uint64
-	DelegPurge   uint64
-	DelegReturn  uint64
-	GetAttr      uint64
-	GetFH        uint64
-	Link         uint64
-	Lock         uint64
-	Lockt        uint64
-	Locku        uint64
-	Lookup       uint64
-	LookupRoot   uint64
-	Nverify      uint64
-	Open         uint64
-	OpenAttr     uint64
-	OpenConfirm  uint64
-	OpenDgrd     uint64
-	PutFH        uint64
-	PutPubFH     uint64
-	PutRootFH    uint64
-	Read         uint64
-	ReadDir      uint64
-	ReadLink     uint64
-	Remove       uint64
-	Rename       uint64
-	Renew        uint64
-	RestoreFH    uint64
-	SaveFH       uint64
-	SecInfo      uint64
-	SetAttr      uint64
-	Verify       uint64
-	Write        uint64
-	RelLockOwner uint64
-}
-
-// ClientRPCStats models all stats from /proc/net/rpc/nfs.
-type ClientRPCStats struct {
-	Network       Network
-	ClientRPC     ClientRPC
-	V2Stats       V2Stats
-	V3Stats       V3Stats
-	ClientV4Stats ClientV4Stats
-}
-
-// ServerRPCStats models all stats from /proc/net/rpc/nfsd.
-type ServerRPCStats struct {
-	ReplyCache     ReplyCache
-	FileHandles    FileHandles
-	InputOutput    InputOutput
-	Threads        Threads
-	ReadAheadCache ReadAheadCache
-	Network        Network
-	ServerRPC      ServerRPC
-	V2Stats        V2Stats
-	V3Stats        V3Stats
-	ServerV4Stats  ServerV4Stats
-	V4Ops          V4Ops
-}

vendor/github.com/prometheus/procfs/nfs/parse.go

@@ -1,317 +0,0 @@
-// Copyright 2018 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package nfs
-
-import (
-	"fmt"
-)
-
-func parseReplyCache(v []uint64) (ReplyCache, error) {
-	if len(v) != 3 {
-		return ReplyCache{}, fmt.Errorf("invalid ReplyCache line %q", v)
-	}
-
-	return ReplyCache{
-		Hits:    v[0],
-		Misses:  v[1],
-		NoCache: v[2],
-	}, nil
-}
-
-func parseFileHandles(v []uint64) (FileHandles, error) {
-	if len(v) != 5 {
-		return FileHandles{}, fmt.Errorf("invalid FileHandles, line %q", v)
-	}
-
-	return FileHandles{
-		Stale:        v[0],
-		TotalLookups: v[1],
-		AnonLookups:  v[2],
-		DirNoCache:   v[3],
-		NoDirNoCache: v[4],
-	}, nil
-}
-
-func parseInputOutput(v []uint64) (InputOutput, error) {
-	if len(v) != 2 {
-		return InputOutput{}, fmt.Errorf("invalid InputOutput line %q", v)
-	}
-
-	return InputOutput{
-		Read:  v[0],
-		Write: v[1],
-	}, nil
-}
-
-func parseThreads(v []uint64) (Threads, error) {
-	if len(v) != 2 {
-		return Threads{}, fmt.Errorf("invalid Threads line %q", v)
-	}
-
-	return Threads{
-		Threads: v[0],
-		FullCnt: v[1],
-	}, nil
-}
-
-func parseReadAheadCache(v []uint64) (ReadAheadCache, error) {
-	if len(v) != 12 {
-		return ReadAheadCache{}, fmt.Errorf("invalid ReadAheadCache line %q", v)
-	}
-
-	return ReadAheadCache{
-		CacheSize:      v[0],
-		CacheHistogram: v[1:11],
-		NotFound:       v[11],
-	}, nil
-}
-
-func parseNetwork(v []uint64) (Network, error) {
-	if len(v) != 4 {
-		return Network{}, fmt.Errorf("invalid Network line %q", v)
-	}
-
-	return Network{
-		NetCount:   v[0],
-		UDPCount:   v[1],
-		TCPCount:   v[2],
-		TCPConnect: v[3],
-	}, nil
-}
-
-func parseServerRPC(v []uint64) (ServerRPC, error) {
-	if len(v) != 5 {
-		return ServerRPC{}, fmt.Errorf("invalid RPC line %q", v)
-	}
-
-	return ServerRPC{
-		RPCCount: v[0],
-		BadCnt:   v[1],
-		BadFmt:   v[2],
-		BadAuth:  v[3],
-		BadcInt:  v[4],
-	}, nil
-}
-
-func parseClientRPC(v []uint64) (ClientRPC, error) {
-	if len(v) != 3 {
-		return ClientRPC{}, fmt.Errorf("invalid RPC line %q", v)
-	}
-
-	return ClientRPC{
-		RPCCount:        v[0],
-		Retransmissions: v[1],
-		AuthRefreshes:   v[2],
-	}, nil
-}
-
-func parseV2Stats(v []uint64) (V2Stats, error) {
-	values := int(v[0])
-	if len(v[1:]) != values || values != 18 {
-		return V2Stats{}, fmt.Errorf("invalid V2Stats line %q", v)
-	}
-
-	return V2Stats{
-		Null:     v[1],
-		GetAttr:  v[2],
-		SetAttr:  v[3],
-		Root:     v[4],
-		Lookup:   v[5],
-		ReadLink: v[6],
-		Read:     v[7],
-		WrCache:  v[8],
-		Write:    v[9],
-		Create:   v[10],
-		Remove:   v[11],
-		Rename:   v[12],
-		Link:     v[13],
-		SymLink:  v[14],
-		MkDir:    v[15],
-		RmDir:    v[16],
-		ReadDir:  v[17],
-		FsStat:   v[18],
-	}, nil
-}
-
-func parseV3Stats(v []uint64) (V3Stats, error) {
-	values := int(v[0])
-	if len(v[1:]) != values || values != 22 {
-		return V3Stats{}, fmt.Errorf("invalid V3Stats line %q", v)
-	}
-
-	return V3Stats{
-		Null:        v[1],
-		GetAttr:     v[2],
-		SetAttr:     v[3],
-		Lookup:      v[4],
-		Access:      v[5],
-		ReadLink:    v[6],
-		Read:        v[7],
-		Write:       v[8],
-		Create:      v[9],
-		MkDir:       v[10],
-		SymLink:     v[11],
-		MkNod:       v[12],
-		Remove:      v[13],
-		RmDir:       v[14],
-		Rename:      v[15],
-		Link:        v[16],
-		ReadDir:     v[17],
-		ReadDirPlus: v[18],
-		FsStat:      v[19],
-		FsInfo:      v[20],
-		PathConf:    v[21],
-		Commit:      v[22],
-	}, nil
-}
-
-func parseClientV4Stats(v []uint64) (ClientV4Stats, error) {
-	values := int(v[0])
-	if len(v[1:]) != values {
-		return ClientV4Stats{}, fmt.Errorf("invalid ClientV4Stats line %q", v)
-	}
-
-	// This function currently supports mapping 59 NFS v4 client stats.  Older
-	// kernels may emit fewer stats, so we must detect this and pad out the
-	// values to match the expected slice size.
-	if values < 59 {
-		newValues := make([]uint64, 60)
-		copy(newValues, v)
-		v = newValues
-	}
-
-	return ClientV4Stats{
-		Null:               v[1],
-		Read:               v[2],
-		Write:              v[3],
-		Commit:             v[4],
-		Open:               v[5],
-		OpenConfirm:        v[6],
-		OpenNoattr:         v[7],
-		OpenDowngrade:      v[8],
-		Close:              v[9],
-		Setattr:            v[10],
-		FsInfo:             v[11],
-		Renew:              v[12],
-		SetClientID:        v[13],
-		SetClientIDConfirm: v[14],
-		Lock:               v[15],
-		Lockt:              v[16],
-		Locku:              v[17],
-		Access:             v[18],
-		Getattr:            v[19],
-		Lookup:             v[20],
-		LookupRoot:         v[21],
-		Remove:             v[22],
-		Rename:             v[23],
-		Link:               v[24],
-		Symlink:            v[25],
-		Create:             v[26],
-		Pathconf:           v[27],
-		StatFs:             v[28],
-		ReadLink:           v[29],
-		ReadDir:            v[30],
-		ServerCaps:         v[31],
-		DelegReturn:        v[32],
-		GetACL:             v[33],
-		SetACL:             v[34],
-		FsLocations:        v[35],
-		ReleaseLockowner:   v[36],
-		Secinfo:            v[37],
-		FsidPresent:        v[38],
-		ExchangeID:         v[39],
-		CreateSession:      v[40],
-		DestroySession:     v[41],
-		Sequence:           v[42],
-		GetLeaseTime:       v[43],
-		ReclaimComplete:    v[44],
-		LayoutGet:          v[45],
-		GetDeviceInfo:      v[46],
-		LayoutCommit:       v[47],
-		LayoutReturn:       v[48],
-		SecinfoNoName:      v[49],
-		TestStateID:        v[50],
-		FreeStateID:        v[51],
-		GetDeviceList:      v[52],
-		BindConnToSession:  v[53],
-		DestroyClientID:    v[54],
-		Seek:               v[55],
-		Allocate:           v[56],
-		DeAllocate:         v[57],
-		LayoutStats:        v[58],
-		Clone:              v[59],
-	}, nil
-}
-
-func parseServerV4Stats(v []uint64) (ServerV4Stats, error) {
-	values := int(v[0])
-	if len(v[1:]) != values || values != 2 {
-		return ServerV4Stats{}, fmt.Errorf("invalid V4Stats line %q", v)
-	}
-
-	return ServerV4Stats{
-		Null:     v[1],
-		Compound: v[2],
-	}, nil
-}
-
-func parseV4Ops(v []uint64) (V4Ops, error) {
-	values := int(v[0])
-	if len(v[1:]) != values || values < 39 {
-		return V4Ops{}, fmt.Errorf("invalid V4Ops line %q", v)
-	}
-
-	stats := V4Ops{
-		Op0Unused:    v[1],
-		Op1Unused:    v[2],
-		Op2Future:    v[3],
-		Access:       v[4],
-		Close:        v[5],
-		Commit:       v[6],
-		Create:       v[7],
-		DelegPurge:   v[8],
-		DelegReturn:  v[9],
-		GetAttr:      v[10],
-		GetFH:        v[11],
-		Link:         v[12],
-		Lock:         v[13],
-		Lockt:        v[14],
-		Locku:        v[15],
-		Lookup:       v[16],
-		LookupRoot:   v[17],
-		Nverify:      v[18],
-		Open:         v[19],
-		OpenAttr:     v[20],
-		OpenConfirm:  v[21],
-		OpenDgrd:     v[22],
-		PutFH:        v[23],
-		PutPubFH:     v[24],
-		PutRootFH:    v[25],
-		Read:         v[26],
-		ReadDir:      v[27],
-		ReadLink:     v[28],
-		Remove:       v[29],
-		Rename:       v[30],
-		Renew:        v[31],
-		RestoreFH:    v[32],
-		SaveFH:       v[33],
-		SecInfo:      v[34],
-		SetAttr:      v[35],
-		Verify:       v[36],
-		Write:        v[37],
-		RelLockOwner: v[38],
-	}
-
-	return stats, nil
-}

vendor/github.com/prometheus/procfs/nfs/parse_nfs.go

@@ -1,67 +0,0 @@
-// Copyright 2018 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package nfs
-
-import (
-	"bufio"
-	"fmt"
-	"io"
-	"strings"
-
-	"github.com/prometheus/procfs/internal/util"
-)
-
-// ParseClientRPCStats returns stats read from /proc/net/rpc/nfs
-func ParseClientRPCStats(r io.Reader) (*ClientRPCStats, error) {
-	stats := &ClientRPCStats{}
-
-	scanner := bufio.NewScanner(r)
-	for scanner.Scan() {
-		line := scanner.Text()
-		parts := strings.Fields(scanner.Text())
-		// require at least <key> <value>
-		if len(parts) < 2 {
-			return nil, fmt.Errorf("invalid NFS metric line %q", line)
-		}
-
-		values, err := util.ParseUint64s(parts[1:])
-		if err != nil {
-			return nil, fmt.Errorf("error parsing NFS metric line: %s", err)
-		}
-
-		switch metricLine := parts[0]; metricLine {
-		case "net":
-			stats.Network, err = parseNetwork(values)
-		case "rpc":
-			stats.ClientRPC, err = parseClientRPC(values)
-		case "proc2":
-			stats.V2Stats, err = parseV2Stats(values)
-		case "proc3":
-			stats.V3Stats, err = parseV3Stats(values)
-		case "proc4":
-			stats.ClientV4Stats, err = parseClientV4Stats(values)
-		default:
-			return nil, fmt.Errorf("unknown NFS metric line %q", metricLine)
-		}
-		if err != nil {
-			return nil, fmt.Errorf("errors parsing NFS metric line: %s", err)
-		}
-	}
-
-	if err := scanner.Err(); err != nil {
-		return nil, fmt.Errorf("error scanning NFS file: %s", err)
-	}
-
-	return stats, nil
-}

vendor/github.com/prometheus/procfs/nfs/parse_nfsd.go

@@ -1,89 +0,0 @@
-// Copyright 2018 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package nfs
-
-import (
-	"bufio"
-	"fmt"
-	"io"
-	"strings"
-
-	"github.com/prometheus/procfs/internal/util"
-)
-
-// ParseServerRPCStats returns stats read from /proc/net/rpc/nfsd
-func ParseServerRPCStats(r io.Reader) (*ServerRPCStats, error) {
-	stats := &ServerRPCStats{}
-
-	scanner := bufio.NewScanner(r)
-	for scanner.Scan() {
-		line := scanner.Text()
-		parts := strings.Fields(scanner.Text())
-		// require at least <key> <value>
-		if len(parts) < 2 {
-			return nil, fmt.Errorf("invalid NFSd metric line %q", line)
-		}
-		label := parts[0]
-
-		var values []uint64
-		var err error
-		if label == "th" {
-			if len(parts) < 3 {
-				return nil, fmt.Errorf("invalid NFSd th metric line %q", line)
-			}
-			values, err = util.ParseUint64s(parts[1:3])
-		} else {
-			values, err = util.ParseUint64s(parts[1:])
-		}
-		if err != nil {
-			return nil, fmt.Errorf("error parsing NFSd metric line: %s", err)
-		}
-
-		switch metricLine := parts[0]; metricLine {
-		case "rc":
-			stats.ReplyCache, err = parseReplyCache(values)
-		case "fh":
-			stats.FileHandles, err = parseFileHandles(values)
-		case "io":
-			stats.InputOutput, err = parseInputOutput(values)
-		case "th":
-			stats.Threads, err = parseThreads(values)
-		case "ra":
-			stats.ReadAheadCache, err = parseReadAheadCache(values)
-		case "net":
-			stats.Network, err = parseNetwork(values)
-		case "rpc":
-			stats.ServerRPC, err = parseServerRPC(values)
-		case "proc2":
-			stats.V2Stats, err = parseV2Stats(values)
-		case "proc3":
-			stats.V3Stats, err = parseV3Stats(values)
-		case "proc4":
-			stats.ServerV4Stats, err = parseServerV4Stats(values)
-		case "proc4ops":
-			stats.V4Ops, err = parseV4Ops(values)
-		default:
-			return nil, fmt.Errorf("unknown NFSd metric line %q", metricLine)
-		}
-		if err != nil {
-			return nil, fmt.Errorf("errors parsing NFSd metric line: %s", err)
-		}
-	}
-
-	if err := scanner.Err(); err != nil {
-		return nil, fmt.Errorf("error scanning NFSd file: %s", err)
-	}
-
-	return stats, nil
-}

vendor/github.com/prometheus/procfs/proc.go

@@ -20,6 +20,9 @@ import (
 	"os"
 	"strconv"
 	"strings"
+
+	"github.com/prometheus/procfs/internal/fs"
+	"github.com/prometheus/procfs/internal/util"
 )
 
 // Proc provides information about a running process.
@@ -27,7 +30,7 @@ type Proc struct {
 	// The process ID.
 	PID int
 
-	fs FS
+	fs fs.FS
 }
 
 // Procs represents a list of Proc structs.
@@ -52,7 +55,7 @@ func NewProc(pid int) (Proc, error) {
 	if err != nil {
 		return Proc{}, err
 	}
-	return fs.NewProc(pid)
+	return fs.Proc(pid)
 }
 
 // AllProcs returns a list of all currently available processes under /proc.
@@ -66,28 +69,35 @@ func AllProcs() (Procs, error) {
 
 // Self returns a process for the current process.
 func (fs FS) Self() (Proc, error) {
-	p, err := os.Readlink(fs.Path("self"))
+	p, err := os.Readlink(fs.proc.Path("self"))
 	if err != nil {
 		return Proc{}, err
 	}
-	pid, err := strconv.Atoi(strings.Replace(p, string(fs), "", -1))
+	pid, err := strconv.Atoi(strings.Replace(p, string(fs.proc), "", -1))
 	if err != nil {
 		return Proc{}, err
 	}
-	return fs.NewProc(pid)
+	return fs.Proc(pid)
 }
 
 // NewProc returns a process for the given pid.
+//
+// Deprecated: use fs.Proc() instead
 func (fs FS) NewProc(pid int) (Proc, error) {
-	if _, err := os.Stat(fs.Path(strconv.Itoa(pid))); err != nil {
+	return fs.Proc(pid)
+}
+
+// Proc returns a process for the given pid.
+func (fs FS) Proc(pid int) (Proc, error) {
+	if _, err := os.Stat(fs.proc.Path(strconv.Itoa(pid))); err != nil {
 		return Proc{}, err
 	}
-	return Proc{PID: pid, fs: fs}, nil
+	return Proc{PID: pid, fs: fs.proc}, nil
 }
 
 // AllProcs returns a list of all currently available processes.
 func (fs FS) AllProcs() (Procs, error) {
-	d, err := os.Open(fs.Path())
+	d, err := os.Open(fs.proc.Path())
 	if err != nil {
 		return Procs{}, err
 	}
@@ -104,7 +114,7 @@ func (fs FS) AllProcs() (Procs, error) {
 		if err != nil {
 			continue
 		}
-		p = append(p, Proc{PID: int(pid), fs: fs})
+		p = append(p, Proc{PID: int(pid), fs: fs.proc})
 	}
 
 	return p, nil
@@ -112,13 +122,7 @@ func (fs FS) AllProcs() (Procs, error) {
 
 // CmdLine returns the command line of a process.
 func (p Proc) CmdLine() ([]string, error) {
-	f, err := os.Open(p.path("cmdline"))
-	if err != nil {
-		return nil, err
-	}
-	defer f.Close()
-
-	data, err := ioutil.ReadAll(f)
+	data, err := util.ReadFileNoStat(p.path("cmdline"))
 	if err != nil {
 		return nil, err
 	}
@@ -132,13 +136,7 @@ func (p Proc) CmdLine() ([]string, error) {
 
 // Comm returns the command name of a process.
 func (p Proc) Comm() (string, error) {
-	f, err := os.Open(p.path("comm"))
-	if err != nil {
-		return "", err
-	}
-	defer f.Close()
-
-	data, err := ioutil.ReadAll(f)
+	data, err := util.ReadFileNoStat(p.path("comm"))
 	if err != nil {
 		return "", err
 	}
@@ -156,6 +154,26 @@ func (p Proc) Executable() (string, error) {
 	return exe, err
 }
 
+// Cwd returns the absolute path to the current working directory of the process.
+func (p Proc) Cwd() (string, error) {
+	wd, err := os.Readlink(p.path("cwd"))
+	if os.IsNotExist(err) {
+		return "", nil
+	}
+
+	return wd, err
+}
+
+// RootDir returns the absolute path to the process's root directory (as set by chroot)
+func (p Proc) RootDir() (string, error) {
+	rdir, err := os.Readlink(p.path("root"))
+	if os.IsNotExist(err) {
+		return "", nil
+	}
+
+	return rdir, err
+}
+
 // FileDescriptors returns the currently open file descriptors of a process.
 func (p Proc) FileDescriptors() ([]uintptr, error) {
 	names, err := p.fileDescriptors()
@@ -218,6 +236,18 @@ func (p Proc) MountStats() ([]*Mount, error) {
 	return parseMountStats(f)
 }
 
+// MountInfo retrieves mount information for mount points in a
+// process's namespace.
+// It supplies information missing in `/proc/self/mounts` and
+// fixes various other problems with that file too.
+func (p Proc) MountInfo() ([]*MountInfo, error) {
+	data, err := util.ReadFileNoStat(p.path("mountinfo"))
+	if err != nil {
+		return nil, err
+	}
+	return parseMountInfo(data)
+}
+
 func (p Proc) fileDescriptors() ([]string, error) {
 	d, err := os.Open(p.path("fd"))
 	if err != nil {
@@ -236,3 +266,33 @@ func (p Proc) fileDescriptors() ([]string, error) {
 func (p Proc) path(pa ...string) string {
 	return p.fs.Path(append([]string{strconv.Itoa(p.PID)}, pa...)...)
 }
+
+// FileDescriptorsInfo retrieves information about all file descriptors of
+// the process.
+func (p Proc) FileDescriptorsInfo() (ProcFDInfos, error) {
+	names, err := p.fileDescriptors()
+	if err != nil {
+		return nil, err
+	}
+
+	var fdinfos ProcFDInfos
+
+	for _, n := range names {
+		fdinfo, err := p.FDInfo(n)
+		if err != nil {
+			continue
+		}
+		fdinfos = append(fdinfos, *fdinfo)
+	}
+
+	return fdinfos, nil
+}
+
+// Schedstat returns task scheduling information for the process.
+func (p Proc) Schedstat() (ProcSchedstat, error) {
+	contents, err := ioutil.ReadFile(p.path("schedstat"))
+	if err != nil {
+		return ProcSchedstat{}, err
+	}
+	return parseProcSchedstat(string(contents))
+}

vendor/github.com/prometheus/procfs/proc_environ.go

@@ -0,0 +1,37 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// Environ reads process environments from /proc/<pid>/environ
+func (p Proc) Environ() ([]string, error) {
+	environments := make([]string, 0)
+
+	data, err := util.ReadFileNoStat(p.path("environ"))
+	if err != nil {
+		return environments, err
+	}
+
+	environments = strings.Split(string(data), "\000")
+	if len(environments) > 0 {
+		environments = environments[:len(environments)-1]
+	}
+
+	return environments, nil
+}

vendor/github.com/prometheus/procfs/proc_fdinfo.go

@@ -0,0 +1,133 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"regexp"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// Regexp variables
+var (
+	rPos          = regexp.MustCompile(`^pos:\s+(\d+)$`)
+	rFlags        = regexp.MustCompile(`^flags:\s+(\d+)$`)
+	rMntID        = regexp.MustCompile(`^mnt_id:\s+(\d+)$`)
+	rInotify      = regexp.MustCompile(`^inotify`)
+	rInotifyParts = regexp.MustCompile(`^inotify\s+wd:([0-9a-f]+)\s+ino:([0-9a-f]+)\s+sdev:([0-9a-f]+)(?:\s+mask:([0-9a-f]+))?`)
+)
+
+// ProcFDInfo contains represents file descriptor information.
+type ProcFDInfo struct {
+	// File descriptor
+	FD string
+	// File offset
+	Pos string
+	// File access mode and status flags
+	Flags string
+	// Mount point ID
+	MntID string
+	// List of inotify lines (structed) in the fdinfo file (kernel 3.8+ only)
+	InotifyInfos []InotifyInfo
+}
+
+// FDInfo constructor. On kernels older than 3.8, InotifyInfos will always be empty.
+func (p Proc) FDInfo(fd string) (*ProcFDInfo, error) {
+	data, err := util.ReadFileNoStat(p.path("fdinfo", fd))
+	if err != nil {
+		return nil, err
+	}
+
+	var text, pos, flags, mntid string
+	var inotify []InotifyInfo
+
+	scanner := bufio.NewScanner(bytes.NewReader(data))
+	for scanner.Scan() {
+		text = scanner.Text()
+		if rPos.MatchString(text) {
+			pos = rPos.FindStringSubmatch(text)[1]
+		} else if rFlags.MatchString(text) {
+			flags = rFlags.FindStringSubmatch(text)[1]
+		} else if rMntID.MatchString(text) {
+			mntid = rMntID.FindStringSubmatch(text)[1]
+		} else if rInotify.MatchString(text) {
+			newInotify, err := parseInotifyInfo(text)
+			if err != nil {
+				return nil, err
+			}
+			inotify = append(inotify, *newInotify)
+		}
+	}
+
+	i := &ProcFDInfo{
+		FD:           fd,
+		Pos:          pos,
+		Flags:        flags,
+		MntID:        mntid,
+		InotifyInfos: inotify,
+	}
+
+	return i, nil
+}
+
+// InotifyInfo represents a single inotify line in the fdinfo file.
+type InotifyInfo struct {
+	// Watch descriptor number
+	WD string
+	// Inode number
+	Ino string
+	// Device ID
+	Sdev string
+	// Mask of events being monitored
+	Mask string
+}
+
+// InotifyInfo constructor. Only available on kernel 3.8+.
+func parseInotifyInfo(line string) (*InotifyInfo, error) {
+	m := rInotifyParts.FindStringSubmatch(line)
+	if len(m) >= 4 {
+		var mask string
+		if len(m) == 5 {
+			mask = m[4]
+		}
+		i := &InotifyInfo{
+			WD:   m[1],
+			Ino:  m[2],
+			Sdev: m[3],
+			Mask: mask,
+		}
+		return i, nil
+	}
+	return nil, errors.New("invalid inode entry: " + line)
+}
+
+// ProcFDInfos represents a list of ProcFDInfo structs.
+type ProcFDInfos []ProcFDInfo
+
+func (p ProcFDInfos) Len() int           { return len(p) }
+func (p ProcFDInfos) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+func (p ProcFDInfos) Less(i, j int) bool { return p[i].FD < p[j].FD }
+
+// InotifyWatchLen returns the total number of inotify watches
+func (p ProcFDInfos) InotifyWatchLen() (int, error) {
+	length := 0
+	for _, f := range p {
+		length += len(f.InotifyInfos)
+	}
+
+	return length, nil
+}

vendor/github.com/prometheus/procfs/proc_io.go

@@ -15,8 +15,8 @@ package procfs
 
 import (
 	"fmt"
-	"io/ioutil"
-	"os"
+
+	"github.com/prometheus/procfs/internal/util"
 )
 
 // ProcIO models the content of /proc/<pid>/io.
@@ -39,17 +39,11 @@ type ProcIO struct {
 	CancelledWriteBytes int64
 }
 
-// NewIO creates a new ProcIO instance from a given Proc instance.
-func (p Proc) NewIO() (ProcIO, error) {
+// IO creates a new ProcIO instance from a given Proc instance.
+func (p Proc) IO() (ProcIO, error) {
 	pio := ProcIO{}
 
-	f, err := os.Open(p.path("io"))
-	if err != nil {
-		return pio, err
-	}
-	defer f.Close()
-
-	data, err := ioutil.ReadAll(f)
+	data, err := util.ReadFileNoStat(p.path("io"))
 	if err != nil {
 		return pio, err
 	}

vendor/github.com/prometheus/procfs/proc_limits.go

@@ -78,7 +78,14 @@ var (
 )
 
 // NewLimits returns the current soft limits of the process.
+//
+// Deprecated: use p.Limits() instead
 func (p Proc) NewLimits() (ProcLimits, error) {
+	return p.Limits()
+}
+
+// Limits returns the current soft limits of the process.
+func (p Proc) Limits() (ProcLimits, error) {
 	f, err := os.Open(p.path("limits"))
 	if err != nil {
 		return ProcLimits{}, err

vendor/github.com/prometheus/procfs/proc_maps.go

@@ -0,0 +1,208 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !windows
+
+package procfs
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+
+	"golang.org/x/sys/unix"
+)
+
+type ProcMapPermissions struct {
+	// mapping has the [R]ead flag set
+	Read bool
+	// mapping has the [W]rite flag set
+	Write bool
+	// mapping has the [X]ecutable flag set
+	Execute bool
+	// mapping has the [S]hared flag set
+	Shared bool
+	// mapping is marked as [P]rivate (copy on write)
+	Private bool
+}
+
+// ProcMap contains the process memory-mappings of the process,
+// read from /proc/[pid]/maps
+type ProcMap struct {
+	// The start address of current mapping.
+	StartAddr uintptr
+	// The end address of the current mapping
+	EndAddr uintptr
+	// The permissions for this mapping
+	Perms *ProcMapPermissions
+	// The current offset into the file/fd (e.g., shared libs)
+	Offset int64
+	// Device owner of this mapping (major:minor) in Mkdev format.
+	Dev uint64
+	// The inode of the device above
+	Inode uint64
+	// The file or psuedofile (or empty==anonymous)
+	Pathname string
+}
+
+// parseDevice parses the device token of a line and converts it to a dev_t
+// (mkdev) like structure.
+func parseDevice(s string) (uint64, error) {
+	toks := strings.Split(s, ":")
+	if len(toks) < 2 {
+		return 0, fmt.Errorf("unexpected number of fields")
+	}
+
+	major, err := strconv.ParseUint(toks[0], 16, 0)
+	if err != nil {
+		return 0, err
+	}
+
+	minor, err := strconv.ParseUint(toks[1], 16, 0)
+	if err != nil {
+		return 0, err
+	}
+
+	return unix.Mkdev(uint32(major), uint32(minor)), nil
+}
+
+// parseAddress just converts a hex-string to a uintptr
+func parseAddress(s string) (uintptr, error) {
+	a, err := strconv.ParseUint(s, 16, 0)
+	if err != nil {
+		return 0, err
+	}
+
+	return uintptr(a), nil
+}
+
+// parseAddresses parses the start-end address
+func parseAddresses(s string) (uintptr, uintptr, error) {
+	toks := strings.Split(s, "-")
+	if len(toks) < 2 {
+		return 0, 0, fmt.Errorf("invalid address")
+	}
+
+	saddr, err := parseAddress(toks[0])
+	if err != nil {
+		return 0, 0, err
+	}
+
+	eaddr, err := parseAddress(toks[1])
+	if err != nil {
+		return 0, 0, err
+	}
+
+	return saddr, eaddr, nil
+}
+
+// parsePermissions parses a token and returns any that are set.
+func parsePermissions(s string) (*ProcMapPermissions, error) {
+	if len(s) < 4 {
+		return nil, fmt.Errorf("invalid permissions token")
+	}
+
+	perms := ProcMapPermissions{}
+	for _, ch := range s {
+		switch ch {
+		case 'r':
+			perms.Read = true
+		case 'w':
+			perms.Write = true
+		case 'x':
+			perms.Execute = true
+		case 'p':
+			perms.Private = true
+		case 's':
+			perms.Shared = true
+		}
+	}
+
+	return &perms, nil
+}
+
+// parseProcMap will attempt to parse a single line within a proc/[pid]/maps
+// buffer.
+func parseProcMap(text string) (*ProcMap, error) {
+	fields := strings.Fields(text)
+	if len(fields) < 5 {
+		return nil, fmt.Errorf("truncated procmap entry")
+	}
+
+	saddr, eaddr, err := parseAddresses(fields[0])
+	if err != nil {
+		return nil, err
+	}
+
+	perms, err := parsePermissions(fields[1])
+	if err != nil {
+		return nil, err
+	}
+
+	offset, err := strconv.ParseInt(fields[2], 16, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	device, err := parseDevice(fields[3])
+	if err != nil {
+		return nil, err
+	}
+
+	inode, err := strconv.ParseUint(fields[4], 10, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	pathname := ""
+
+	if len(fields) >= 5 {
+		pathname = strings.Join(fields[5:], " ")
+	}
+
+	return &ProcMap{
+		StartAddr: saddr,
+		EndAddr:   eaddr,
+		Perms:     perms,
+		Offset:    offset,
+		Dev:       device,
+		Inode:     inode,
+		Pathname:  pathname,
+	}, nil
+}
+
+// ProcMaps reads from /proc/[pid]/maps to get the memory-mappings of the
+// process.
+func (p Proc) ProcMaps() ([]*ProcMap, error) {
+	file, err := os.Open(p.path("maps"))
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	maps := []*ProcMap{}
+	scan := bufio.NewScanner(file)
+
+	for scan.Scan() {
+		m, err := parseProcMap(scan.Text())
+		if err != nil {
+			return nil, err
+		}
+
+		maps = append(maps, m)
+	}
+
+	return maps, nil
+}

vendor/github.com/prometheus/procfs/proc_ns.go

@@ -29,9 +29,9 @@ type Namespace struct {
 // Namespaces contains all of the namespaces that the process is contained in.
 type Namespaces map[string]Namespace
 
-// NewNamespaces reads from /proc/[pid/ns/* to get the namespaces of which the
+// Namespaces reads from /proc/<pid>/ns/* to get the namespaces of which the
 // process is a member.
-func (p Proc) NewNamespaces() (Namespaces, error) {
+func (p Proc) Namespaces() (Namespaces, error) {
 	d, err := os.Open(p.path("ns"))
 	if err != nil {
 		return nil, err

vendor/github.com/prometheus/procfs/proc_psi.go

@@ -0,0 +1,100 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+// The PSI / pressure interface is described at
+//   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/accounting/psi.txt
+// Each resource (cpu, io, memory, ...) is exposed as a single file.
+// Each file may contain up to two lines, one for "some" pressure and one for "full" pressure.
+// Each line contains several averages (over n seconds) and a total in µs.
+//
+// Example io pressure file:
+// > some avg10=0.06 avg60=0.21 avg300=0.99 total=8537362
+// > full avg10=0.00 avg60=0.13 avg300=0.96 total=8183134
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+const lineFormat = "avg10=%f avg60=%f avg300=%f total=%d"
+
+// PSILine is a single line of values as returned by /proc/pressure/*
+// The Avg entries are averages over n seconds, as a percentage
+// The Total line is in microseconds
+type PSILine struct {
+	Avg10  float64
+	Avg60  float64
+	Avg300 float64
+	Total  uint64
+}
+
+// PSIStats represent pressure stall information from /proc/pressure/*
+// Some indicates the share of time in which at least some tasks are stalled
+// Full indicates the share of time in which all non-idle tasks are stalled simultaneously
+type PSIStats struct {
+	Some *PSILine
+	Full *PSILine
+}
+
+// PSIStatsForResource reads pressure stall information for the specified
+// resource from /proc/pressure/<resource>. At time of writing this can be
+// either "cpu", "memory" or "io".
+func (fs FS) PSIStatsForResource(resource string) (PSIStats, error) {
+	data, err := util.ReadFileNoStat(fs.proc.Path(fmt.Sprintf("%s/%s", "pressure", resource)))
+	if err != nil {
+		return PSIStats{}, fmt.Errorf("psi_stats: unavailable for %s", resource)
+	}
+
+	return parsePSIStats(resource, bytes.NewReader(data))
+}
+
+// parsePSIStats parses the specified file for pressure stall information
+func parsePSIStats(resource string, r io.Reader) (PSIStats, error) {
+	psiStats := PSIStats{}
+
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		l := scanner.Text()
+		prefix := strings.Split(l, " ")[0]
+		switch prefix {
+		case "some":
+			psi := PSILine{}
+			_, err := fmt.Sscanf(l, fmt.Sprintf("some %s", lineFormat), &psi.Avg10, &psi.Avg60, &psi.Avg300, &psi.Total)
+			if err != nil {
+				return PSIStats{}, err
+			}
+			psiStats.Some = &psi
+		case "full":
+			psi := PSILine{}
+			_, err := fmt.Sscanf(l, fmt.Sprintf("full %s", lineFormat), &psi.Avg10, &psi.Avg60, &psi.Avg300, &psi.Total)
+			if err != nil {
+				return PSIStats{}, err
+			}
+			psiStats.Full = &psi
+		default:
+			// If we encounter a line with an unknown prefix, ignore it and move on
+			// Should new measurement types be added in the future we'll simply ignore them instead
+			// of erroring on retrieval
+			continue
+		}
+	}
+
+	return psiStats, nil
+}

vendor/github.com/prometheus/procfs/proc_stat.go

@@ -16,8 +16,10 @@ package procfs
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
+
+	"github.com/prometheus/procfs/internal/fs"
+	"github.com/prometheus/procfs/internal/util"
 )
 
 // Originally, this USER_HZ value was dynamically retrieved via a sysconf call
@@ -95,22 +97,23 @@ type ProcStat struct {
 	// in clock ticks.
 	Starttime uint64
 	// Virtual memory size in bytes.
-	VSize int
+	VSize uint
 	// Resident set size in pages.
 	RSS int
 
-	fs FS
+	proc fs.FS
 }
 
 // NewStat returns the current status information of the process.
+//
+// Deprecated: use p.Stat() instead
 func (p Proc) NewStat() (ProcStat, error) {
-	f, err := os.Open(p.path("stat"))
-	if err != nil {
-		return ProcStat{}, err
-	}
-	defer f.Close()
+	return p.Stat()
+}
 
-	data, err := ioutil.ReadAll(f)
+// Stat returns the current status information of the process.
+func (p Proc) Stat() (ProcStat, error) {
+	data, err := util.ReadFileNoStat(p.path("stat"))
 	if err != nil {
 		return ProcStat{}, err
 	}
@@ -118,7 +121,7 @@ func (p Proc) NewStat() (ProcStat, error) {
 	var (
 		ignore int
 
-		s = ProcStat{PID: p.PID, fs: p.fs}
+		s = ProcStat{PID: p.PID, proc: p.fs}
 		l = bytes.Index(data, []byte("("))
 		r = bytes.LastIndex(data, []byte(")"))
 	)
@@ -164,7 +167,7 @@ func (p Proc) NewStat() (ProcStat, error) {
 }
 
 // VirtualMemory returns the virtual memory size in bytes.
-func (s ProcStat) VirtualMemory() int {
+func (s ProcStat) VirtualMemory() uint {
 	return s.VSize
 }
 
@@ -175,7 +178,8 @@ func (s ProcStat) ResidentMemory() int {
 
 // StartTime returns the unix timestamp of the process in seconds.
 func (s ProcStat) StartTime() (float64, error) {
-	stat, err := s.fs.NewStat()
+	fs := FS{proc: s.proc}
+	stat, err := fs.Stat()
 	if err != nil {
 		return 0, err
 	}

vendor/github.com/prometheus/procfs/proc_status.go

@@ -0,0 +1,166 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bytes"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// ProcStatus provides status information about the process,
+// read from /proc/[pid]/stat.
+type ProcStatus struct {
+	// The process ID.
+	PID int
+	// The process name.
+	Name string
+
+	// Thread group ID.
+	TGID int
+
+	// Peak virtual memory size.
+	VmPeak uint64 // nolint:golint
+	// Virtual memory size.
+	VmSize uint64 // nolint:golint
+	// Locked memory size.
+	VmLck uint64 // nolint:golint
+	// Pinned memory size.
+	VmPin uint64 // nolint:golint
+	// Peak resident set size.
+	VmHWM uint64 // nolint:golint
+	// Resident set size (sum of RssAnnon RssFile and RssShmem).
+	VmRSS uint64 // nolint:golint
+	// Size of resident anonymous memory.
+	RssAnon uint64 // nolint:golint
+	// Size of resident file mappings.
+	RssFile uint64 // nolint:golint
+	// Size of resident shared memory.
+	RssShmem uint64 // nolint:golint
+	// Size of data segments.
+	VmData uint64 // nolint:golint
+	// Size of stack segments.
+	VmStk uint64 // nolint:golint
+	// Size of text segments.
+	VmExe uint64 // nolint:golint
+	// Shared library code size.
+	VmLib uint64 // nolint:golint
+	// Page table entries size.
+	VmPTE uint64 // nolint:golint
+	// Size of second-level page tables.
+	VmPMD uint64 // nolint:golint
+	// Swapped-out virtual memory size by anonymous private.
+	VmSwap uint64 // nolint:golint
+	// Size of hugetlb memory portions
+	HugetlbPages uint64
+
+	// Number of voluntary context switches.
+	VoluntaryCtxtSwitches uint64
+	// Number of involuntary context switches.
+	NonVoluntaryCtxtSwitches uint64
+
+	// UIDs of the process (Real, effective, saved set, and filesystem UIDs (GIDs))
+	UIDs [4]string
+}
+
+// NewStatus returns the current status information of the process.
+func (p Proc) NewStatus() (ProcStatus, error) {
+	data, err := util.ReadFileNoStat(p.path("status"))
+	if err != nil {
+		return ProcStatus{}, err
+	}
+
+	s := ProcStatus{PID: p.PID}
+
+	lines := strings.Split(string(data), "\n")
+	for _, line := range lines {
+		if !bytes.Contains([]byte(line), []byte(":")) {
+			continue
+		}
+
+		kv := strings.SplitN(line, ":", 2)
+
+		// removes spaces
+		k := string(strings.TrimSpace(kv[0]))
+		v := string(strings.TrimSpace(kv[1]))
+		// removes "kB"
+		v = string(bytes.Trim([]byte(v), " kB"))
+
+		// value to int when possible
+		// we can skip error check here, 'cause vKBytes is not used when value is a string
+		vKBytes, _ := strconv.ParseUint(v, 10, 64)
+		// convert kB to B
+		vBytes := vKBytes * 1024
+
+		s.fillStatus(k, v, vKBytes, vBytes)
+	}
+
+	return s, nil
+}
+
+func (s *ProcStatus) fillStatus(k string, vString string, vUint uint64, vUintBytes uint64) {
+	switch k {
+	case "Tgid":
+		s.TGID = int(vUint)
+	case "Name":
+		s.Name = vString
+	case "Uid":
+		copy(s.UIDs[:], strings.Split(vString, "\t"))
+	case "VmPeak":
+		s.VmPeak = vUintBytes
+	case "VmSize":
+		s.VmSize = vUintBytes
+	case "VmLck":
+		s.VmLck = vUintBytes
+	case "VmPin":
+		s.VmPin = vUintBytes
+	case "VmHWM":
+		s.VmHWM = vUintBytes
+	case "VmRSS":
+		s.VmRSS = vUintBytes
+	case "RssAnon":
+		s.RssAnon = vUintBytes
+	case "RssFile":
+		s.RssFile = vUintBytes
+	case "RssShmem":
+		s.RssShmem = vUintBytes
+	case "VmData":
+		s.VmData = vUintBytes
+	case "VmStk":
+		s.VmStk = vUintBytes
+	case "VmExe":
+		s.VmExe = vUintBytes
+	case "VmLib":
+		s.VmLib = vUintBytes
+	case "VmPTE":
+		s.VmPTE = vUintBytes
+	case "VmPMD":
+		s.VmPMD = vUintBytes
+	case "VmSwap":
+		s.VmSwap = vUintBytes
+	case "HugetlbPages":
+		s.HugetlbPages = vUintBytes
+	case "voluntary_ctxt_switches":
+		s.VoluntaryCtxtSwitches = vUint
+	case "nonvoluntary_ctxt_switches":
+		s.NonVoluntaryCtxtSwitches = vUint
+	}
+}
+
+// TotalCtxtSwitches returns the total context switch.
+func (s ProcStatus) TotalCtxtSwitches() uint64 {
+	return s.VoluntaryCtxtSwitches + s.NonVoluntaryCtxtSwitches
+}

vendor/github.com/prometheus/procfs/schedstat.go

@@ -0,0 +1,118 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"errors"
+	"os"
+	"regexp"
+	"strconv"
+)
+
+var (
+	cpuLineRE  = regexp.MustCompile(`cpu(\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+)`)
+	procLineRE = regexp.MustCompile(`(\d+) (\d+) (\d+)`)
+)
+
+// Schedstat contains scheduler statistics from /proc/schedstat
+//
+// See
+// https://www.kernel.org/doc/Documentation/scheduler/sched-stats.txt
+// for a detailed description of what these numbers mean.
+//
+// Note the current kernel documentation claims some of the time units are in
+// jiffies when they are actually in nanoseconds since 2.6.23 with the
+// introduction of CFS. A fix to the documentation is pending. See
+// https://lore.kernel.org/patchwork/project/lkml/list/?series=403473
+type Schedstat struct {
+	CPUs []*SchedstatCPU
+}
+
+// SchedstatCPU contains the values from one "cpu<N>" line
+type SchedstatCPU struct {
+	CPUNum string
+
+	RunningNanoseconds uint64
+	WaitingNanoseconds uint64
+	RunTimeslices      uint64
+}
+
+// ProcSchedstat contains the values from /proc/<pid>/schedstat
+type ProcSchedstat struct {
+	RunningNanoseconds uint64
+	WaitingNanoseconds uint64
+	RunTimeslices      uint64
+}
+
+// Schedstat reads data from /proc/schedstat
+func (fs FS) Schedstat() (*Schedstat, error) {
+	file, err := os.Open(fs.proc.Path("schedstat"))
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	stats := &Schedstat{}
+	scanner := bufio.NewScanner(file)
+
+	for scanner.Scan() {
+		match := cpuLineRE.FindStringSubmatch(scanner.Text())
+		if match != nil {
+			cpu := &SchedstatCPU{}
+			cpu.CPUNum = match[1]
+
+			cpu.RunningNanoseconds, err = strconv.ParseUint(match[8], 10, 64)
+			if err != nil {
+				continue
+			}
+
+			cpu.WaitingNanoseconds, err = strconv.ParseUint(match[9], 10, 64)
+			if err != nil {
+				continue
+			}
+
+			cpu.RunTimeslices, err = strconv.ParseUint(match[10], 10, 64)
+			if err != nil {
+				continue
+			}
+
+			stats.CPUs = append(stats.CPUs, cpu)
+		}
+	}
+
+	return stats, nil
+}
+
+func parseProcSchedstat(contents string) (stats ProcSchedstat, err error) {
+	match := procLineRE.FindStringSubmatch(contents)
+
+	if match != nil {
+		stats.RunningNanoseconds, err = strconv.ParseUint(match[1], 10, 64)
+		if err != nil {
+			return
+		}
+
+		stats.WaitingNanoseconds, err = strconv.ParseUint(match[2], 10, 64)
+		if err != nil {
+			return
+		}
+
+		stats.RunTimeslices, err = strconv.ParseUint(match[3], 10, 64)
+		return
+	}
+
+	err = errors.New("could not parse schedstat")
+	return
+}