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Log stderr when e2e ssh commands fail #5868

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Merged
merged 1 commit into from
Sep 12, 2025
Merged

Log stderr when e2e ssh commands fail #5868

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12 changes: 5 additions & 7 deletions test/e2e/helpers.go
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Original file line number Diff line number Diff line change
Expand Up @@ -488,7 +488,7 @@ func getProxiedSSHClient(controlPlaneEndpoint, hostname, port string, ioTimeout

// execOnHost runs the specified command directly on a node's host, using a SSH connection
// proxied through a control plane host and copies the output to a file.
func execOnHost(controlPlaneEndpoint, hostname, port string, ioTimeout time.Duration, f io.StringWriter, command string,
func execOnHost(controlPlaneEndpoint, hostname, port string, ioTimeout time.Duration, f io.Writer, command string,
args ...string) error {
client, err := getProxiedSSHClient(controlPlaneEndpoint, hostname, port, ioTimeout)
if err != nil {
Expand All @@ -502,16 +502,14 @@ func execOnHost(controlPlaneEndpoint, hostname, port string, ioTimeout time.Dura
defer session.Close()

// Run the command and write the captured stdout to the file
var stdoutBuf bytes.Buffer
session.Stdout = &stdoutBuf
var stderrBuf bytes.Buffer
session.Stdout = f
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@nojnhuh nojnhuh Sep 12, 2025

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Getting rid of the intermediate stdoutBuf is a drive-by optimization to save us from holding onto the entire file content in memory before writing it to the file.

session.Stderr = &stderrBuf
if len(args) > 0 {
command += " " + strings.Join(args, " ")
}
if err = session.Run(command); err != nil {
return errors.Wrapf(err, "running command \"%s\"", command)
}
if _, err = f.WriteString(stdoutBuf.String()); err != nil {
return errors.Wrap(err, "writing output to file")
return fmt.Errorf("running command %q: %w, stderr: %s", command, err, strings.TrimSpace(stderrBuf.String()))
}

return nil
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