DockerCLI/cli/command/container/stats_helpers.go

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package container
import (
"encoding/json"
"io"
"strings"
"sync"
"time"
"github.com/docker/cli/cli/command/formatter"
"github.com/docker/docker/api/types"
"github.com/docker/docker/client"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"golang.org/x/net/context"
)
type stats struct {
mu sync.Mutex
cs []*formatter.ContainerStats
}
// daemonOSType is set once we have at least one stat for a container
// from the daemon. It is used to ensure we print the right header based
// on the daemon platform.
var daemonOSType string
func (s *stats) add(cs *formatter.ContainerStats) bool {
s.mu.Lock()
defer s.mu.Unlock()
if _, exists := s.isKnownContainer(cs.Container); !exists {
s.cs = append(s.cs, cs)
return true
}
return false
}
func (s *stats) remove(id string) {
s.mu.Lock()
if i, exists := s.isKnownContainer(id); exists {
s.cs = append(s.cs[:i], s.cs[i+1:]...)
}
s.mu.Unlock()
}
func (s *stats) isKnownContainer(cid string) (int, bool) {
for i, c := range s.cs {
if c.Container == cid {
return i, true
}
}
return -1, false
}
func collect(ctx context.Context, s *formatter.ContainerStats, cli client.APIClient, streamStats bool, waitFirst *sync.WaitGroup) {
logrus.Debugf("collecting stats for %s", s.Container)
var (
getFirst bool
previousCPU uint64
previousSystem uint64
u = make(chan error, 1)
)
defer func() {
// if error happens and we get nothing of stats, release wait group whatever
if !getFirst {
getFirst = true
waitFirst.Done()
}
}()
response, err := cli.ContainerStats(ctx, s.Container, streamStats)
if err != nil {
s.SetError(err)
return
}
defer response.Body.Close()
dec := json.NewDecoder(response.Body)
go func() {
for {
var (
v *types.StatsJSON
memPercent, cpuPercent float64
blkRead, blkWrite uint64 // Only used on Linux
mem, memLimit float64
pidsStatsCurrent uint64
)
if err := dec.Decode(&v); err != nil {
dec = json.NewDecoder(io.MultiReader(dec.Buffered(), response.Body))
u <- err
if err == io.EOF {
break
}
time.Sleep(100 * time.Millisecond)
continue
}
daemonOSType = response.OSType
if daemonOSType != "windows" {
previousCPU = v.PreCPUStats.CPUUsage.TotalUsage
previousSystem = v.PreCPUStats.SystemUsage
cpuPercent = calculateCPUPercentUnix(previousCPU, previousSystem, v)
blkRead, blkWrite = calculateBlockIO(v.BlkioStats)
mem = calculateMemUsageUnixNoCache(v.MemoryStats)
memLimit = float64(v.MemoryStats.Limit)
memPercent = calculateMemPercentUnixNoCache(memLimit, mem)
pidsStatsCurrent = v.PidsStats.Current
} else {
cpuPercent = calculateCPUPercentWindows(v)
blkRead = v.StorageStats.ReadSizeBytes
blkWrite = v.StorageStats.WriteSizeBytes
mem = float64(v.MemoryStats.PrivateWorkingSet)
}
netRx, netTx := calculateNetwork(v.Networks)
s.SetStatistics(formatter.StatsEntry{
Name: v.Name,
ID: v.ID,
CPUPercentage: cpuPercent,
Memory: mem,
MemoryPercentage: memPercent,
MemoryLimit: memLimit,
NetworkRx: netRx,
NetworkTx: netTx,
BlockRead: float64(blkRead),
BlockWrite: float64(blkWrite),
PidsCurrent: pidsStatsCurrent,
})
u <- nil
if !streamStats {
return
}
}
}()
for {
select {
case <-time.After(2 * time.Second):
// zero out the values if we have not received an update within
// the specified duration.
s.SetErrorAndReset(errors.New("timeout waiting for stats"))
// if this is the first stat you get, release WaitGroup
if !getFirst {
getFirst = true
waitFirst.Done()
}
case err := <-u:
s.SetError(err)
if err == io.EOF {
break
}
if err != nil {
continue
}
// if this is the first stat you get, release WaitGroup
if !getFirst {
getFirst = true
waitFirst.Done()
}
}
if !streamStats {
return
}
}
}
func calculateCPUPercentUnix(previousCPU, previousSystem uint64, v *types.StatsJSON) float64 {
var (
cpuPercent = 0.0
// calculate the change for the cpu usage of the container in between readings
cpuDelta = float64(v.CPUStats.CPUUsage.TotalUsage) - float64(previousCPU)
// calculate the change for the entire system between readings
systemDelta = float64(v.CPUStats.SystemUsage) - float64(previousSystem)
onlineCPUs = float64(v.CPUStats.OnlineCPUs)
)
if onlineCPUs == 0.0 {
onlineCPUs = float64(len(v.CPUStats.CPUUsage.PercpuUsage))
}
if systemDelta > 0.0 && cpuDelta > 0.0 {
cpuPercent = (cpuDelta / systemDelta) * onlineCPUs * 100.0
}
return cpuPercent
}
func calculateCPUPercentWindows(v *types.StatsJSON) float64 {
// Max number of 100ns intervals between the previous time read and now
possIntervals := uint64(v.Read.Sub(v.PreRead).Nanoseconds()) // Start with number of ns intervals
possIntervals /= 100 // Convert to number of 100ns intervals
possIntervals *= uint64(v.NumProcs) // Multiple by the number of processors
// Intervals used
intervalsUsed := v.CPUStats.CPUUsage.TotalUsage - v.PreCPUStats.CPUUsage.TotalUsage
// Percentage avoiding divide-by-zero
if possIntervals > 0 {
return float64(intervalsUsed) / float64(possIntervals) * 100.0
}
return 0.00
}
func calculateBlockIO(blkio types.BlkioStats) (blkRead uint64, blkWrite uint64) {
for _, bioEntry := range blkio.IoServiceBytesRecursive {
switch strings.ToLower(bioEntry.Op) {
case "read":
blkRead = blkRead + bioEntry.Value
case "write":
blkWrite = blkWrite + bioEntry.Value
}
}
return
}
func calculateNetwork(network map[string]types.NetworkStats) (float64, float64) {
var rx, tx float64
for _, v := range network {
rx += float64(v.RxBytes)
tx += float64(v.TxBytes)
}
return rx, tx
}
// calculateMemUsageUnixNoCache calculate memory usage of the container.
// Page cache is intentionally excluded to avoid misinterpretation of the output.
func calculateMemUsageUnixNoCache(mem types.MemoryStats) float64 {
return float64(mem.Usage - mem.Stats["cache"])
}
func calculateMemPercentUnixNoCache(limit float64, usedNoCache float64) float64 {
// MemoryStats.Limit will never be 0 unless the container is not running and we haven't
// got any data from cgroup
if limit != 0 {
return usedNoCache / limit * 100.0
}
return 0
}