sqshq/sampler · error

failed to execute command: %s

Error message

failed to execute command: %s

What it means

The basic interactive shell wraps any error from starting or communicating with the underlying command (cmd.Start / related exec calls) into "failed to execute command: <underlying error>". After repeated failures beyond errorThreshold, the library also drops the cached shell (item.basicShell = nil) so a fresh session is started next time. The root cause is always in the wrapped err string.

Source

Thrown at data/int_basic.go:93

	}

	return nil
}

func (s *BasicInteractiveShell) execute() (string, error) {

	if s.stdin == nil {
		return "", nil
	}

	_, err := io.WriteString(s.stdin, fmt.Sprintf(" %s\n", s.item.sampleScript))
	if err != nil {
		s.errCount++
		if s.errCount > errorThreshold {
			_ = s.cmd.Wait()
			s.item.basicShell = nil // restart session
		}
		return "", fmt.Errorf("failed to execute command: %s", err)
	}

	timeout := make(chan bool, 1)

	go func() {
		time.Sleep(s.timeout)
		timeout <- true
	}()

	var resultText strings.Builder
	var errorText strings.Builder

	for {
		select {
		case stdout := <-s.stdoutCh:
			if len(stdout) > 0 {
				resultText.WriteString(stdout)
				resultText.WriteString("\n")

View on GitHub (pinned to 9bc7ba732d)

Solutions

  1. Read the wrapped underlying error (after the colon) and fix that cause first (PATH, binary name, permissions)
  2. Use an absolute path to the executable in the item configuration
  3. Verify the command runs under the same user/environment the collector runs as (echo $PATH)
  4. Check the working directory and file permissions if the error mentions chdir or permission denied

Example fix

// before
script: myscript.sh
// after
script: /opt/scripts/myscript.sh  # absolute path, chmod +x applied
Defensive patterns

Strategy: try-catch

Validate before calling

path, err := exec.LookPath(cmdName)
if err != nil { return fmt.Errorf("command %q not found in PATH", cmdName) }

Try / catch

out, err := shell.execute()
var execErr *exec.Error
if err != nil {
    if errors.As(err, &execErr) {
        log.Fatalf("fix PATH or binary name: %v", execErr)
    }
    return err
}

Prevention

When it happens

Trigger: cmd.Start fails when running a command through the basic interactive shell — e.g. executable not on PATH, bad working directory, missing binary permissions — or repeated session errors tripping errorThreshold and forcing a session restart.

Common situations: Typo'd or missing command name in the item config; command present interactively but not in the collector's PATH (cron/systemd environments); script without execute bit; cwd removed.

Related errors

AI-assisted analysis of sqshq/sampler@9bc7ba732d (2026-09-06). Data as JSON: /api/errors/4ec8ce75593387bd. Report an issue: GitHub.