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[1.21] oci: wait until pidfile to be written before starting timer #5093

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Merged
openshift-merge-robot merged 4 commits into from
Jul 19, 2021
Merged

[1.21] oci: wait until pidfile to be written before starting timer #5093

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90bc8f9
vendor: add notify package
haircommander Jul 16, 2021
0420874
oci: refactor fsnotify usage
haircommander Jul 9, 2021
9f95a84
oci: wait for runtime to write pidfile before starting timer
haircommander Jul 9, 2021
fd6dcf3
oci: be more precise about channels and routines
haircommander Jul 16, 2021
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oci: be more precise about channels and routines 
Be careful about leaking anything

Signed-off-by: Peter Hunt <[email protected]>
  • Loading branch information
@haircommander
haircommander committed Jul 16, 2021
commit fd6dcf33dc69bf8164ccf26fd1f2a9229940c851
36 changes: 28 additions & 8 deletions internal/oci/runtime_oci.go
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Original file line number Diff line number Diff line change
Expand Up @@ -343,7 +343,8 @@ func (r *runtimeOCI) ExecSyncContainer(ctx context.Context, c *Container, comman
cmd.Stdout = &stdoutBuf
cmd.Stderr = &stderrBuf

pidFileCreatedCh, err := WatchForFile(pidFile, notify.InModify, notify.InMovedTo)
pidFileCreatedDone := make(chan struct{}, 1)
pidFileCreatedCh, err := WatchForFile(pidFile, pidFileCreatedDone, notify.InModify, notify.InMovedTo)
if err != nil {
return nil, errors.Wrapf(err, "failed to watch %s", pidFile)
}
Expand All @@ -357,6 +358,7 @@ func (r *runtimeOCI) ExecSyncContainer(ctx context.Context, c *Container, comman
done := make(chan error, 1)
go func() {
done <- cmd.Wait()
close(done)
}()

// First, wait for the pid file to be created.
Expand All @@ -366,8 +368,8 @@ func (r *runtimeOCI) ExecSyncContainer(ctx context.Context, c *Container, comman
select {
case <-pidFileCreatedCh:
case doneErr = <-done:
close(done)
}
close(pidFileCreatedDone)

switch {
case doneErr != nil:
Expand Down Expand Up @@ -1039,15 +1041,22 @@ func (r *runtimeOCI) ReopenContainerLog(ctx context.Context, c *Container) error
}
defer controlFile.Close()

ch, err := WatchForFile(c.LogPath(), notify.InCreate, notify.InModify)
done := make(chan struct{}, 1)
ch, err := WatchForFile(c.LogPath(), done, notify.InCreate, notify.InModify)
if err != nil {
return errors.Wrapf(err, "failed to create watch for %s", c.LogPath())
}

if _, err = fmt.Fprintf(controlFile, "%d %d %d\n", 2, 0, 0); err != nil {
log.Debugf(ctx, "Failed to write to control file to reopen log file: %v", err)
}
<-ch
select {
case <-ch:
case <-time.After(time.Minute * 3):
// Give up after 3 minutes, as something wrong probably happened
log.Errorf(ctx, "Failed to reopen log file for container %s: timed out", c.ID())
}
close(done)

return nil
}
Expand Down Expand Up @@ -1092,7 +1101,11 @@ func (c *Container) conmonPidFilePath() string {
return filepath.Join(c.bundlePath, "conmon-pidfile")
}

func WatchForFile(path string, opsToWatch ...notify.Event) (chan struct{}, error) {
// WatchForFile creates a watch on the parent directory of path, looking for events opsToWatch.
// It returns immediately with a channel to find when path had one of those events.
// done can be used to stop the watch.
// WatchForFile is responsible for closing all internal channels and the returned channel, but not for closing done.
func WatchForFile(path string, done chan struct{}, opsToWatch ...notify.Event) (chan struct{}, error) {
eiCh := make(chan notify.EventInfo, 1)
ch := make(chan struct{})

Expand All @@ -1101,10 +1114,17 @@ func WatchForFile(path string, opsToWatch ...notify.Event) (chan struct{}, error
return nil, err
}
go func() {
defer close(ch)
defer close(eiCh)
defer notify.Stop(eiCh)
for ei := range eiCh {
if ei.Path() == path {
ch <- struct{}{}
for {
select {
case ei := <-eiCh:
if ei.Path() == path {
ch <- struct{}{}
return
}
case <-done:
return
}
}
Expand Down
18 changes: 15 additions & 3 deletions internal/oci/runtime_oci_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -147,12 +147,14 @@ var _ = t.Describe("Oci", func() {
})
t.Describe("WatchForFile", func() {
var notifyFile string
var done chan struct{}
BeforeEach(func() {
notifyFile = filepath.Join(t.MustTempDir("watch"), "file")
done = make(chan struct{}, 1)
})
It("should catch file creation", func() {
// Given
ch, err := oci.WatchForFile(notifyFile, notify.InCreate, notify.InModify)
ch, err := oci.WatchForFile(notifyFile, done, notify.InCreate, notify.InModify)
Expect(err).To(BeNil())

// When
Expand All @@ -164,7 +166,7 @@ var _ = t.Describe("Oci", func() {
})
It("should not catch file create if doesn't exist", func() {
// Given
ch, err := oci.WatchForFile(notifyFile, notify.InCreate, notify.InModify)
ch, err := oci.WatchForFile(notifyFile, done, notify.InCreate, notify.InModify)
Expect(err).To(BeNil())

// When
Expand All @@ -182,7 +184,7 @@ var _ = t.Describe("Oci", func() {
})
It("should only catch file write", func() {
// Given
ch, err := oci.WatchForFile(notifyFile, notify.InModify)
ch, err := oci.WatchForFile(notifyFile, done, notify.InModify)
Expect(err).To(BeNil())

// When
Expand All @@ -197,6 +199,16 @@ var _ = t.Describe("Oci", func() {

<-ch
})
It("should give up after sending on done", func() {
// Given
ch, err := oci.WatchForFile(notifyFile, done, notify.InModify)
Expect(err).To(BeNil())

// When
checkChannelEmpty(ch)
done <- struct{}{}
<-ch
})
})
})

Expand Down