DockerCLI/vendor/google.golang.org/grpc/stream.go

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/*
*
* Copyright 2014 gRPC 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 grpc
import (
"errors"
"io"
"sync"
"time"
"golang.org/x/net/context"
"golang.org/x/net/trace"
"google.golang.org/grpc/balancer"
"google.golang.org/grpc/channelz"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/encoding"
"google.golang.org/grpc/metadata"
"google.golang.org/grpc/stats"
"google.golang.org/grpc/status"
"google.golang.org/grpc/transport"
)
// StreamHandler defines the handler called by gRPC server to complete the
// execution of a streaming RPC. If a StreamHandler returns an error, it
// should be produced by the status package, or else gRPC will use
// codes.Unknown as the status code and err.Error() as the status message
// of the RPC.
type StreamHandler func(srv interface{}, stream ServerStream) error
// StreamDesc represents a streaming RPC service's method specification.
type StreamDesc struct {
StreamName string
Handler StreamHandler
// At least one of these is true.
ServerStreams bool
ClientStreams bool
}
// Stream defines the common interface a client or server stream has to satisfy.
//
// All errors returned from Stream are compatible with the status package.
type Stream interface {
// Context returns the context for this stream.
Context() context.Context
// SendMsg blocks until it sends m, the stream is done or the stream
// breaks.
// On error, it aborts the stream and returns an RPC status on client
// side. On server side, it simply returns the error to the caller.
// SendMsg is called by generated code. Also Users can call SendMsg
// directly when it is really needed in their use cases.
// It's safe to have a goroutine calling SendMsg and another goroutine calling
// recvMsg on the same stream at the same time.
// But it is not safe to call SendMsg on the same stream in different goroutines.
SendMsg(m interface{}) error
// RecvMsg blocks until it receives a message or the stream is
// done. On client side, it returns io.EOF when the stream is done. On
// any other error, it aborts the stream and returns an RPC status. On
// server side, it simply returns the error to the caller.
// It's safe to have a goroutine calling SendMsg and another goroutine calling
// recvMsg on the same stream at the same time.
// But it is not safe to call RecvMsg on the same stream in different goroutines.
RecvMsg(m interface{}) error
}
// ClientStream defines the interface a client stream has to satisfy.
type ClientStream interface {
// Header returns the header metadata received from the server if there
// is any. It blocks if the metadata is not ready to read.
Header() (metadata.MD, error)
// Trailer returns the trailer metadata from the server, if there is any.
// It must only be called after stream.CloseAndRecv has returned, or
// stream.Recv has returned a non-nil error (including io.EOF).
Trailer() metadata.MD
// CloseSend closes the send direction of the stream. It closes the stream
// when non-nil error is met.
CloseSend() error
// Stream.SendMsg() may return a non-nil error when something wrong happens sending
// the request. The returned error indicates the status of this sending, not the final
// status of the RPC.
//
// Always call Stream.RecvMsg() to drain the stream and get the final
// status, otherwise there could be leaked resources.
Stream
}
// NewStream creates a new Stream for the client side. This is typically
// called by generated code.
func (cc *ClientConn) NewStream(ctx context.Context, desc *StreamDesc, method string, opts ...CallOption) (ClientStream, error) {
// allow interceptor to see all applicable call options, which means those
// configured as defaults from dial option as well as per-call options
opts = combine(cc.dopts.callOptions, opts)
if cc.dopts.streamInt != nil {
return cc.dopts.streamInt(ctx, desc, cc, method, newClientStream, opts...)
}
return newClientStream(ctx, desc, cc, method, opts...)
}
// NewClientStream creates a new Stream for the client side. This is typically
// called by generated code.
//
// DEPRECATED: Use ClientConn.NewStream instead.
func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error) {
return cc.NewStream(ctx, desc, method, opts...)
}
func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (_ ClientStream, err error) {
if channelz.IsOn() {
cc.incrCallsStarted()
defer func() {
if err != nil {
cc.incrCallsFailed()
}
}()
}
c := defaultCallInfo()
mc := cc.GetMethodConfig(method)
if mc.WaitForReady != nil {
c.failFast = !*mc.WaitForReady
}
// Possible context leak:
// The cancel function for the child context we create will only be called
// when RecvMsg returns a non-nil error, if the ClientConn is closed, or if
// an error is generated by SendMsg.
// https://github.com/grpc/grpc-go/issues/1818.
var cancel context.CancelFunc
if mc.Timeout != nil && *mc.Timeout >= 0 {
ctx, cancel = context.WithTimeout(ctx, *mc.Timeout)
} else {
ctx, cancel = context.WithCancel(ctx)
}
defer func() {
if err != nil {
cancel()
}
}()
for _, o := range opts {
if err := o.before(c); err != nil {
return nil, toRPCErr(err)
}
}
c.maxSendMessageSize = getMaxSize(mc.MaxReqSize, c.maxSendMessageSize, defaultClientMaxSendMessageSize)
c.maxReceiveMessageSize = getMaxSize(mc.MaxRespSize, c.maxReceiveMessageSize, defaultClientMaxReceiveMessageSize)
if err := setCallInfoCodec(c); err != nil {
return nil, err
}
callHdr := &transport.CallHdr{
Host: cc.authority,
Method: method,
// If it's not client streaming, we should already have the request to be sent,
// so we don't flush the header.
// If it's client streaming, the user may never send a request or send it any
// time soon, so we ask the transport to flush the header.
Flush: desc.ClientStreams,
ContentSubtype: c.contentSubtype,
}
// Set our outgoing compression according to the UseCompressor CallOption, if
// set. In that case, also find the compressor from the encoding package.
// Otherwise, use the compressor configured by the WithCompressor DialOption,
// if set.
var cp Compressor
var comp encoding.Compressor
if ct := c.compressorType; ct != "" {
callHdr.SendCompress = ct
if ct != encoding.Identity {
comp = encoding.GetCompressor(ct)
if comp == nil {
return nil, status.Errorf(codes.Internal, "grpc: Compressor is not installed for requested grpc-encoding %q", ct)
}
}
} else if cc.dopts.cp != nil {
callHdr.SendCompress = cc.dopts.cp.Type()
cp = cc.dopts.cp
}
if c.creds != nil {
callHdr.Creds = c.creds
}
var trInfo traceInfo
if EnableTracing {
trInfo.tr = trace.New("grpc.Sent."+methodFamily(method), method)
trInfo.firstLine.client = true
if deadline, ok := ctx.Deadline(); ok {
trInfo.firstLine.deadline = deadline.Sub(time.Now())
}
trInfo.tr.LazyLog(&trInfo.firstLine, false)
ctx = trace.NewContext(ctx, trInfo.tr)
defer func() {
if err != nil {
// Need to call tr.finish() if error is returned.
// Because tr will not be returned to caller.
trInfo.tr.LazyPrintf("RPC: [%v]", err)
trInfo.tr.SetError()
trInfo.tr.Finish()
}
}()
}
ctx = newContextWithRPCInfo(ctx, c.failFast)
sh := cc.dopts.copts.StatsHandler
var beginTime time.Time
if sh != nil {
ctx = sh.TagRPC(ctx, &stats.RPCTagInfo{FullMethodName: method, FailFast: c.failFast})
beginTime = time.Now()
begin := &stats.Begin{
Client: true,
BeginTime: beginTime,
FailFast: c.failFast,
}
sh.HandleRPC(ctx, begin)
defer func() {
if err != nil {
// Only handle end stats if err != nil.
end := &stats.End{
Client: true,
Error: err,
BeginTime: beginTime,
EndTime: time.Now(),
}
sh.HandleRPC(ctx, end)
}
}()
}
var (
t transport.ClientTransport
s *transport.Stream
done func(balancer.DoneInfo)
)
for {
// Check to make sure the context has expired. This will prevent us from
// looping forever if an error occurs for wait-for-ready RPCs where no data
// is sent on the wire.
select {
case <-ctx.Done():
return nil, toRPCErr(ctx.Err())
default:
}
t, done, err = cc.getTransport(ctx, c.failFast)
if err != nil {
return nil, err
}
s, err = t.NewStream(ctx, callHdr)
if err != nil {
if done != nil {
done(balancer.DoneInfo{Err: err})
done = nil
}
// In the event of any error from NewStream, we never attempted to write
// anything to the wire, so we can retry indefinitely for non-fail-fast
// RPCs.
if !c.failFast {
continue
}
return nil, toRPCErr(err)
}
break
}
cs := &clientStream{
opts: opts,
c: c,
cc: cc,
desc: desc,
codec: c.codec,
cp: cp,
comp: comp,
cancel: cancel,
attempt: &csAttempt{
t: t,
s: s,
p: &parser{r: s},
done: done,
dc: cc.dopts.dc,
ctx: ctx,
trInfo: trInfo,
statsHandler: sh,
beginTime: beginTime,
},
}
cs.c.stream = cs
cs.attempt.cs = cs
if desc != unaryStreamDesc {
// Listen on cc and stream contexts to cleanup when the user closes the
// ClientConn or cancels the stream context. In all other cases, an error
// should already be injected into the recv buffer by the transport, which
// the client will eventually receive, and then we will cancel the stream's
// context in clientStream.finish.
go func() {
select {
case <-cc.ctx.Done():
cs.finish(ErrClientConnClosing)
case <-ctx.Done():
cs.finish(toRPCErr(ctx.Err()))
}
}()
}
return cs, nil
}
// clientStream implements a client side Stream.
type clientStream struct {
opts []CallOption
c *callInfo
cc *ClientConn
desc *StreamDesc
codec baseCodec
cp Compressor
comp encoding.Compressor
cancel context.CancelFunc // cancels all attempts
sentLast bool // sent an end stream
mu sync.Mutex // guards finished
finished bool // TODO: replace with atomic cmpxchg or sync.Once?
attempt *csAttempt // the active client stream attempt
// TODO(hedging): hedging will have multiple attempts simultaneously.
}
// csAttempt implements a single transport stream attempt within a
// clientStream.
type csAttempt struct {
cs *clientStream
t transport.ClientTransport
s *transport.Stream
p *parser
done func(balancer.DoneInfo)
dc Decompressor
decomp encoding.Compressor
decompSet bool
ctx context.Context // the application's context, wrapped by stats/tracing
mu sync.Mutex // guards trInfo.tr
// trInfo.tr is set when created (if EnableTracing is true),
// and cleared when the finish method is called.
trInfo traceInfo
statsHandler stats.Handler
beginTime time.Time
}
func (cs *clientStream) Context() context.Context {
// TODO(retry): commit the current attempt (the context has peer-aware data).
return cs.attempt.context()
}
func (cs *clientStream) Header() (metadata.MD, error) {
m, err := cs.attempt.header()
if err != nil {
// TODO(retry): maybe retry on error or commit attempt on success.
err = toRPCErr(err)
cs.finish(err)
}
return m, err
}
func (cs *clientStream) Trailer() metadata.MD {
// TODO(retry): on error, maybe retry (trailers-only).
return cs.attempt.trailer()
}
func (cs *clientStream) SendMsg(m interface{}) (err error) {
// TODO(retry): buffer message for replaying if not committed.
return cs.attempt.sendMsg(m)
}
func (cs *clientStream) RecvMsg(m interface{}) (err error) {
// TODO(retry): maybe retry on error or commit attempt on success.
return cs.attempt.recvMsg(m)
}
func (cs *clientStream) CloseSend() error {
cs.attempt.closeSend()
return nil
}
func (cs *clientStream) finish(err error) {
if err == io.EOF {
// Ending a stream with EOF indicates a success.
err = nil
}
cs.mu.Lock()
if cs.finished {
cs.mu.Unlock()
return
}
cs.finished = true
cs.mu.Unlock()
if channelz.IsOn() {
if err != nil {
cs.cc.incrCallsFailed()
} else {
cs.cc.incrCallsSucceeded()
}
}
// TODO(retry): commit current attempt if necessary.
cs.attempt.finish(err)
for _, o := range cs.opts {
o.after(cs.c)
}
cs.cancel()
}
func (a *csAttempt) context() context.Context {
return a.s.Context()
}
func (a *csAttempt) header() (metadata.MD, error) {
return a.s.Header()
}
func (a *csAttempt) trailer() metadata.MD {
return a.s.Trailer()
}
func (a *csAttempt) sendMsg(m interface{}) (err error) {
// TODO Investigate how to signal the stats handling party.
// generate error stats if err != nil && err != io.EOF?
cs := a.cs
defer func() {
// For non-client-streaming RPCs, we return nil instead of EOF on success
// because the generated code requires it. finish is not called; RecvMsg()
// will call it with the stream's status independently.
if err == io.EOF && !cs.desc.ClientStreams {
err = nil
}
if err != nil && err != io.EOF {
// Call finish on the client stream for errors generated by this SendMsg
// call, as these indicate problems created by this client. (Transport
// errors are converted to an io.EOF error below; the real error will be
// returned from RecvMsg eventually in that case, or be retried.)
cs.finish(err)
}
}()
// TODO: Check cs.sentLast and error if we already ended the stream.
if EnableTracing {
a.mu.Lock()
if a.trInfo.tr != nil {
a.trInfo.tr.LazyLog(&payload{sent: true, msg: m}, true)
}
a.mu.Unlock()
}
var outPayload *stats.OutPayload
if a.statsHandler != nil {
outPayload = &stats.OutPayload{
Client: true,
}
}
hdr, data, err := encode(cs.codec, m, cs.cp, outPayload, cs.comp)
if err != nil {
return err
}
if len(data) > *cs.c.maxSendMessageSize {
return status.Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(data), *cs.c.maxSendMessageSize)
}
if !cs.desc.ClientStreams {
cs.sentLast = true
}
err = a.t.Write(a.s, hdr, data, &transport.Options{Last: !cs.desc.ClientStreams})
if err == nil {
if outPayload != nil {
outPayload.SentTime = time.Now()
a.statsHandler.HandleRPC(a.ctx, outPayload)
}
if channelz.IsOn() {
a.t.IncrMsgSent()
}
return nil
}
return io.EOF
}
func (a *csAttempt) recvMsg(m interface{}) (err error) {
cs := a.cs
defer func() {
if err != nil || !cs.desc.ServerStreams {
// err != nil or non-server-streaming indicates end of stream.
cs.finish(err)
}
}()
var inPayload *stats.InPayload
if a.statsHandler != nil {
inPayload = &stats.InPayload{
Client: true,
}
}
if !a.decompSet {
// Block until we receive headers containing received message encoding.
if ct := a.s.RecvCompress(); ct != "" && ct != encoding.Identity {
if a.dc == nil || a.dc.Type() != ct {
// No configured decompressor, or it does not match the incoming
// message encoding; attempt to find a registered compressor that does.
a.dc = nil
a.decomp = encoding.GetCompressor(ct)
}
} else {
// No compression is used; disable our decompressor.
a.dc = nil
}
// Only initialize this state once per stream.
a.decompSet = true
}
err = recv(a.p, cs.codec, a.s, a.dc, m, *cs.c.maxReceiveMessageSize, inPayload, a.decomp)
if err != nil {
if err == io.EOF {
if statusErr := a.s.Status().Err(); statusErr != nil {
return statusErr
}
return io.EOF // indicates successful end of stream.
}
return toRPCErr(err)
}
if EnableTracing {
a.mu.Lock()
if a.trInfo.tr != nil {
a.trInfo.tr.LazyLog(&payload{sent: false, msg: m}, true)
}
a.mu.Unlock()
}
if inPayload != nil {
a.statsHandler.HandleRPC(a.ctx, inPayload)
}
if channelz.IsOn() {
a.t.IncrMsgRecv()
}
if cs.desc.ServerStreams {
// Subsequent messages should be received by subsequent RecvMsg calls.
return nil
}
// Special handling for non-server-stream rpcs.
// This recv expects EOF or errors, so we don't collect inPayload.
err = recv(a.p, cs.codec, a.s, a.dc, m, *cs.c.maxReceiveMessageSize, nil, a.decomp)
if err == nil {
return toRPCErr(errors.New("grpc: client streaming protocol violation: get <nil>, want <EOF>"))
}
if err == io.EOF {
return a.s.Status().Err() // non-server streaming Recv returns nil on success
}
return toRPCErr(err)
}
func (a *csAttempt) closeSend() {
cs := a.cs
if cs.sentLast {
return
}
cs.sentLast = true
cs.attempt.t.Write(cs.attempt.s, nil, nil, &transport.Options{Last: true})
// We ignore errors from Write. Any error it would return would also be
// returned by a subsequent RecvMsg call, and the user is supposed to always
// finish the stream by calling RecvMsg until it returns err != nil.
}
func (a *csAttempt) finish(err error) {
a.mu.Lock()
a.t.CloseStream(a.s, err)
if a.done != nil {
a.done(balancer.DoneInfo{
Err: err,
BytesSent: true,
BytesReceived: a.s.BytesReceived(),
})
}
if a.statsHandler != nil {
end := &stats.End{
Client: true,
BeginTime: a.beginTime,
EndTime: time.Now(),
Error: err,
}
a.statsHandler.HandleRPC(a.ctx, end)
}
if a.trInfo.tr != nil {
if err == nil {
a.trInfo.tr.LazyPrintf("RPC: [OK]")
} else {
a.trInfo.tr.LazyPrintf("RPC: [%v]", err)
a.trInfo.tr.SetError()
}
a.trInfo.tr.Finish()
a.trInfo.tr = nil
}
a.mu.Unlock()
}
// ServerStream defines the interface a server stream has to satisfy.
type ServerStream interface {
// SetHeader sets the header metadata. It may be called multiple times.
// When call multiple times, all the provided metadata will be merged.
// All the metadata will be sent out when one of the following happens:
// - ServerStream.SendHeader() is called;
// - The first response is sent out;
// - An RPC status is sent out (error or success).
SetHeader(metadata.MD) error
// SendHeader sends the header metadata.
// The provided md and headers set by SetHeader() will be sent.
// It fails if called multiple times.
SendHeader(metadata.MD) error
// SetTrailer sets the trailer metadata which will be sent with the RPC status.
// When called more than once, all the provided metadata will be merged.
SetTrailer(metadata.MD)
Stream
}
// serverStream implements a server side Stream.
type serverStream struct {
ctx context.Context
t transport.ServerTransport
s *transport.Stream
p *parser
codec baseCodec
cp Compressor
dc Decompressor
comp encoding.Compressor
decomp encoding.Compressor
maxReceiveMessageSize int
maxSendMessageSize int
trInfo *traceInfo
statsHandler stats.Handler
mu sync.Mutex // protects trInfo.tr after the service handler runs.
}
func (ss *serverStream) Context() context.Context {
return ss.ctx
}
func (ss *serverStream) SetHeader(md metadata.MD) error {
if md.Len() == 0 {
return nil
}
return ss.s.SetHeader(md)
}
func (ss *serverStream) SendHeader(md metadata.MD) error {
return ss.t.WriteHeader(ss.s, md)
}
func (ss *serverStream) SetTrailer(md metadata.MD) {
if md.Len() == 0 {
return
}
ss.s.SetTrailer(md)
}
func (ss *serverStream) SendMsg(m interface{}) (err error) {
defer func() {
if ss.trInfo != nil {
ss.mu.Lock()
if ss.trInfo.tr != nil {
if err == nil {
ss.trInfo.tr.LazyLog(&payload{sent: true, msg: m}, true)
} else {
ss.trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
ss.trInfo.tr.SetError()
}
}
ss.mu.Unlock()
}
if err != nil && err != io.EOF {
st, _ := status.FromError(toRPCErr(err))
ss.t.WriteStatus(ss.s, st)
}
if channelz.IsOn() && err == nil {
ss.t.IncrMsgSent()
}
}()
var outPayload *stats.OutPayload
if ss.statsHandler != nil {
outPayload = &stats.OutPayload{}
}
hdr, data, err := encode(ss.codec, m, ss.cp, outPayload, ss.comp)
if err != nil {
return err
}
if len(data) > ss.maxSendMessageSize {
return status.Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(data), ss.maxSendMessageSize)
}
if err := ss.t.Write(ss.s, hdr, data, &transport.Options{Last: false}); err != nil {
return toRPCErr(err)
}
if outPayload != nil {
outPayload.SentTime = time.Now()
ss.statsHandler.HandleRPC(ss.s.Context(), outPayload)
}
return nil
}
func (ss *serverStream) RecvMsg(m interface{}) (err error) {
defer func() {
if ss.trInfo != nil {
ss.mu.Lock()
if ss.trInfo.tr != nil {
if err == nil {
ss.trInfo.tr.LazyLog(&payload{sent: false, msg: m}, true)
} else if err != io.EOF {
ss.trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
ss.trInfo.tr.SetError()
}
}
ss.mu.Unlock()
}
if err != nil && err != io.EOF {
st, _ := status.FromError(toRPCErr(err))
ss.t.WriteStatus(ss.s, st)
}
if channelz.IsOn() && err == nil {
ss.t.IncrMsgRecv()
}
}()
var inPayload *stats.InPayload
if ss.statsHandler != nil {
inPayload = &stats.InPayload{}
}
if err := recv(ss.p, ss.codec, ss.s, ss.dc, m, ss.maxReceiveMessageSize, inPayload, ss.decomp); err != nil {
if err == io.EOF {
return err
}
if err == io.ErrUnexpectedEOF {
err = status.Errorf(codes.Internal, io.ErrUnexpectedEOF.Error())
}
return toRPCErr(err)
}
if inPayload != nil {
ss.statsHandler.HandleRPC(ss.s.Context(), inPayload)
}
return nil
}
// MethodFromServerStream returns the method string for the input stream.
// The returned string is in the format of "/service/method".
func MethodFromServerStream(stream ServerStream) (string, bool) {
return Method(stream.Context())
}