opensource/podman
1
0
Fork 0
mirror of https://github.com/containers/podman.git synced 2025-07-04 18:27:33 +08:00
Code Issues Packages Projects Releases Wiki Activity

fix podman top missing output flake

Browse Source 
Sometimes there is no output displayed from the podman top command but
no error is shown either. Looking at the code I think the issue here is
that we do not wait for the output reader to end as it runs in a
different goroutine. Thus the last lines of output might be missing.

The fix is simply to wait for said goroutine to finish before returning.
While at it also fix the missing scanner error check and return the read
errors back to the caller.

[NO NEW TESTS NEEDED] It is a flake.

Fixes #19504

Signed-off-by: Paul Holzinger <pholzing@redhat.com>
This commit is contained in:
Paul Holzinger
2023-08-11 13:15:39 +02:00
parent a60bafea48
commit 4b80492bd2
1 changed files with 20 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
libpod/container_top_linux.go
View File

@ -297,19 +297,24 @@ func (c *Container) execPS(psArgs []string) ([]string, bool, error) {
if err != nil {
return nil, false, err
}
defer wPipe.Close()
defer rPipe.Close()
outErrChan := make(chan error)
stdout := []string{}
go func() {
defer close(outErrChan)
scanner := bufio.NewScanner(rPipe)
for scanner.Scan() {
stdout = append(stdout, scanner.Text())
}
if err := scanner.Err(); err != nil {
outErrChan <- err
}
}()
psPath, err := exec.LookPath("ps")
if err != nil {
wPipe.Close()
return nil, true, err
}
args := append([]string{podmanTopCommand, strconv.Itoa(c.state.PID), psPath}, psArgs...)
@ -326,6 +331,7 @@ func (c *Container) execPS(psArgs []string) ([]string, bool, error) {
retryContainerExec := true
err = cmd.Run()
wPipe.Close()
if err != nil {
exitError := &exec.ExitError{}
if errors.As(err, &exitError) {
@ -342,6 +348,10 @@ func (c *Container) execPS(psArgs []string) ([]string, bool, error) {
err = fmt.Errorf("could not reexec podman-top command: %w", err)
}
}
if err := <-outErrChan; err != nil {
return nil, retryContainerExec, fmt.Errorf("failed to read ps stdout: %w", err)
}
return stdout, retryContainerExec, err
}
@ -352,7 +362,6 @@ func (c *Container) execPSinContainer(args []string) ([]string, error) {
if err != nil {
return nil, err
}
defer wPipe.Close()
defer rPipe.Close()
var errBuf bytes.Buffer
@ -362,18 +371,24 @@ func (c *Container) execPSinContainer(args []string) ([]string, error) {
streams.AttachOutput = true
streams.AttachError = true
outErrChan := make(chan error)
stdout := []string{}
go func() {
defer close(outErrChan)
scanner := bufio.NewScanner(rPipe)
for scanner.Scan() {
stdout = append(stdout, scanner.Text())
}
if err := scanner.Err(); err != nil {
outErrChan <- err
}
}()
cmd := append([]string{"ps"}, args...)
config := new(ExecConfig)
config.Command = cmd
ec, err := c.Exec(config, streams, nil)
wPipe.Close()
if err != nil {
return nil, err
} else if ec != 0 {
@ -386,5 +401,8 @@ func (c *Container) execPSinContainer(args []string) ([]string, error) {
logrus.Debugf(errBuf.String())
}
if err := <-outErrChan; err != nil {
return nil, fmt.Errorf("failed to read ps stdout: %w", err)
}
return stdout, nil
}