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Bug fix: stats --no-stream always print zero values

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`docker stats --no-stream` always print zero values.

```
$ docker stats --no-stream
CONTAINER           CPU %               MEM USAGE / LIMIT   MEM %
NET I/O             BLOCK I/O
7f4ef234ca8c        0.00%               0 B / 0 B           0.00%
0 B / 0 B           0 B / 0 B
f05bd18819aa        0.00%               0 B / 0 B           0.00%
0 B / 0 B           0 B / 0 B

```

This commit will let docker client wait until it gets correct stat
data before print it on screen.

Signed-off-by: Zhang Wei <zhangwei555@huawei.com>
This commit is contained in:
Zhang Wei 2016-03-01 15:09:48 +08:00
parent 361a63e5f2
commit ea86c30a4a
3 changed files with 78 additions and 18 deletions
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33
api/client/stats.go
View file

@ -4,6 +4,7 @@ import (
"fmt"
"io"
"strings"
"sync"
"text/tabwriter"
"time"
@ -59,6 +60,9 @@ func (cli *DockerCli) CmdStats(args ...string) error {
})
}
// waitFirst is a WaitGroup to wait first stat data's reach for each container
waitFirst := &sync.WaitGroup{}
cStats := stats{}
// getContainerList simulates creation event for all previously existing
// containers (only used when calling `docker stats` without arguments).
@ -72,8 +76,10 @@ func (cli *DockerCli) CmdStats(args ...string) error {
}
for _, container := range cs {
s := &containerStats{Name: container.ID[:12]}
cStats.add(s)
go s.Collect(cli.client, !*noStream)
if cStats.add(s) {
waitFirst.Add(1)
go s.Collect(cli.client, !*noStream, waitFirst)
}
}
}
@ -87,15 +93,19 @@ func (cli *DockerCli) CmdStats(args ...string) error {
eh.Handle("create", func(e events.Message) {
if *all {
s := &containerStats{Name: e.ID[:12]}
cStats.add(s)
go s.Collect(cli.client, !*noStream)
if cStats.add(s) {
waitFirst.Add(1)
go s.Collect(cli.client, !*noStream, waitFirst)
}
}
})
eh.Handle("start", func(e events.Message) {
s := &containerStats{Name: e.ID[:12]}
cStats.add(s)
go s.Collect(cli.client, !*noStream)
if cStats.add(s) {
waitFirst.Add(1)
go s.Collect(cli.client, !*noStream, waitFirst)
}
})
eh.Handle("die", func(e events.Message) {
@ -112,14 +122,16 @@ func (cli *DockerCli) CmdStats(args ...string) error {
// Start a short-lived goroutine to retrieve the initial list of
// containers.
go getContainerList()
getContainerList()
} else {
// Artificially send creation events for the containers we were asked to
// monitor (same code path than we use when monitoring all containers).
for _, name := range names {
s := &containerStats{Name: name}
cStats.add(s)
go s.Collect(cli.client, !*noStream)
if cStats.add(s) {
waitFirst.Add(1)
go s.Collect(cli.client, !*noStream, waitFirst)
}
}
// We don't expect any asynchronous errors: closeChan can be closed.
@ -143,6 +155,9 @@ func (cli *DockerCli) CmdStats(args ...string) error {
}
}
// before print to screen, make sure each container get at least one valid stat data
waitFirst.Wait()
w := tabwriter.NewWriter(cli.out, 20, 1, 3, ' ', 0)
printHeader := func() {
if !*noStream {

40
api/client/stats_helpers.go
View file

@ -33,12 +33,14 @@ type stats struct {
cs []*containerStats
}
func (s *stats) add(cs *containerStats) {
func (s *stats) add(cs *containerStats) bool {
s.mu.Lock()
defer s.mu.Unlock()
if _, exists := s.isKnownContainer(cs.Name); !exists {
s.cs = append(s.cs, cs)
return true
}
s.mu.Unlock()
return false
}
func (s *stats) remove(id string) {
@ -58,7 +60,22 @@ func (s *stats) isKnownContainer(cid string) (int, bool) {
return -1, false
}
func (s *containerStats) Collect(cli client.APIClient, streamStats bool) {
func (s *containerStats) Collect(cli client.APIClient, streamStats bool, waitFirst *sync.WaitGroup) {
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()
}
}()
responseBody, err := cli.ContainerStats(context.Background(), s.Name, streamStats)
if err != nil {
s.mu.Lock()
@ -68,12 +85,7 @@ func (s *containerStats) Collect(cli client.APIClient, streamStats bool) {
}
defer responseBody.Close()
var (
previousCPU uint64
previousSystem uint64
dec = json.NewDecoder(responseBody)
u = make(chan error, 1)
)
dec := json.NewDecoder(responseBody)
go func() {
for {
var v *types.StatsJSON
@ -125,6 +137,11 @@ func (s *containerStats) Collect(cli client.APIClient, streamStats bool) {
s.BlockRead = 0
s.BlockWrite = 0
s.mu.Unlock()
// if this is the first stat you get, release WaitGroup
if !getFirst {
getFirst = true
waitFirst.Done()
}
case err := <-u:
if err != nil {
s.mu.Lock()
@ -132,6 +149,11 @@ func (s *containerStats) Collect(cli client.APIClient, streamStats bool) {
s.mu.Unlock()
return
}
// if this is the first stat you get, release WaitGroup
if !getFirst {
getFirst = true
waitFirst.Done()
}
}
if !streamStats {
return

23
integration-cli/docker_cli_stats_test.go
View file

@ -75,6 +75,18 @@ func (s *DockerSuite) TestStatsAllRunningNoStream(c *check.C) {
if strings.Contains(out, id3) {
c.Fatalf("Did not expect %s in stats, got %s", id3, out)
}
// check output contains real data, but not all zeros
reg, _ := regexp.Compile("[1-9]+")
// split output with "\n", outLines[1] is id2's output
// outLines[2] is id1's output
outLines := strings.Split(out, "\n")
// check stat result of id2 contains real data
realData := reg.Find([]byte(outLines[1][12:]))
c.Assert(realData, checker.NotNil, check.Commentf("stat result are empty: %s", out))
// check stat result of id1 contains real data
realData = reg.Find([]byte(outLines[2][12:]))
c.Assert(realData, checker.NotNil, check.Commentf("stat result are empty: %s", out))
}
func (s *DockerSuite) TestStatsAllNoStream(c *check.C) {
@ -93,6 +105,17 @@ func (s *DockerSuite) TestStatsAllNoStream(c *check.C) {
if !strings.Contains(out, id1) || !strings.Contains(out, id2) {
c.Fatalf("Expected stats output to contain both %s and %s, got %s", id1, id2, out)
}
// check output contains real data, but not all zeros
reg, _ := regexp.Compile("[1-9]+")
// split output with "\n", outLines[1] is id2's output
outLines := strings.Split(out, "\n")
// check stat result of id2 contains real data
realData := reg.Find([]byte(outLines[1][12:]))
c.Assert(realData, checker.NotNil, check.Commentf("stat result of %s is empty: %s", id2, out))
// check stat result of id1 contains all zero
realData = reg.Find([]byte(outLines[2][12:]))
c.Assert(realData, checker.IsNil, check.Commentf("stat result of %s should be empty : %s", id1, out))
}
func (s *DockerSuite) TestStatsAllNewContainersAdded(c *check.C) {