larksuite/cli · warning

busdiscover: malformed pid file %s

Error message

busdiscover: malformed pid file %s

What it means

readPIDFile throws this when the bus.pid file exists but does not contain the expected two-line payload (PID line + RFC3339 timestamp line). The scanner (scanLiveBuses via isBusAlive) treats the bus as live but logs this diagnostic and reports the process with PID 0, so it is a data-integrity signal rather than a fatal failure.

Source

Thrown at internal/event/adapter/localbus/busdiscover/pidfile.go:70

		return nil, fmt.Errorf("busdiscover: write pid tmp: %w", err)
	}
	if err := vfs.Rename(tmpPath, pidPath); err != nil {
		_ = vfs.Remove(tmpPath)
		_ = lock.Unlock()
		return nil, fmt.Errorf("busdiscover: rename pid file: %w", err)
	}
	return &Handle{lock: lock}, nil
}

func readPIDFile(eventsDir string) (int, time.Time, error) {
	pidPath := filepath.Join(eventsDir, pidFileName)
	data, err := vfs.ReadFile(pidPath)
	if err != nil {
		return 0, time.Time{}, err
	}
	lines := strings.SplitN(strings.TrimSpace(string(data)), "\n", 2)
	if len(lines) < 2 {
		return 0, time.Time{}, fmt.Errorf("busdiscover: malformed pid file %s", pidPath)
	}
	pid, err := strconv.Atoi(strings.TrimSpace(lines[0]))
	if err != nil {
		return 0, time.Time{}, fmt.Errorf("busdiscover: malformed pid in %s: %w", pidPath, err)
	}
	startTime, err := time.Parse(time.RFC3339, strings.TrimSpace(lines[1]))
	if err != nil {
		return 0, time.Time{}, fmt.Errorf("busdiscover: malformed timestamp in %s: %w", pidPath, err)
	}
	return pid, startTime, nil
}

// isBusAlive: try-lock the alive file. ErrHeld = live holder; success = stale (release immediately).
func isBusAlive(appDir string) bool {
	lockPath := filepath.Join(appDir, aliveLockFileName)
	if _, err := vfs.Stat(lockPath); err != nil {
		return false
	}

View on GitHub (pinned to 7fd6ef3c07)

Solutions

1. Delete the corrupt bus.pid and restart the bus process so WritePIDFile republishes a valid file (the alive lock still proves liveness)
2. Check file content with cat bus.pid — expect '<pid>\n<RFC3339 timestamp>' and fix if manually edited
3. If the owning bus process is dead, remove the whole stale app dir; the try-lock probe will then report it not alive
4. If this recurs, check for disk corruption or tools that rewrite files non-atomically in the state dir

Example fix

// before: truncated pid file -> live bus reported with PID 0
$ cat ~/.larkcli/events/<appID>/bus.pid
1234
// after: delete and let the bus republish
$ rm ~/.larkcli/events/<appID>/bus.pid && restart the bus process
$ cat ~/.larkcli/events/<appID>/bus.pid
1234
2026-09-04T08:00:00Z

// Treat PID 0 as 'liveness known, pid unknown' when consuming scan results
func hasUsablePID(p busdiscover.Process) bool { return p.PID > 0 }

// Validate a pid file's shape before relying on it
func pidFileLooksValid(path string) bool {
    data, err := os.ReadFile(path)
    if err != nil { return false }
    lines := strings.SplitN(strings.TrimSpace(string(data)), "\n", 2)
    if len(lines) < 2 { return false }
    if _, err := strconv.Atoi(strings.TrimSpace(lines[0])); err != nil { return false }
    _, err = time.Parse(time.RFC3339, strings.TrimSpace(lines[1]))
    return err == nil
}

procs, err := scanLiveBuses(eventsDir) // readPIDFile failure is logged, not returned
for _, p := range procs {
    if p.PID == 0 {
        // live lock held but pid file unreadable: cannot signal; treat as unmanaged live bus
        continue
    }
    // safe to signal p.PID
}

When it happens

Trigger: A live-lock-holding app directory contains a bus.pid whose trimmed content has fewer than two newline-separated lines — e.g. empty file, single-line file, or a file truncated/corrupted by a crash between creation and the atomic rename of an older writer.

Common situations: Manual edits or truncation of bus.pid, a crash or kill before any successful rename completed, disk corruption, or a third-party tool rewriting the file in an unexpected format.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• busdiscover: malformed pid in %s: %w
• busdiscover: mkdir %s: %w
• busdiscover: write pid tmp: %w
• busdiscover: rename pid file: %w
• busdiscover: malformed timestamp in %s: %w

AI-assisted analysis of larksuite/cli@7fd6ef3c07 (2026-09-04). Data as JSON: /api/errors/5625ea249f69beb8. Report an issue: GitHub.