Function Write

internal/pidfile/pidfile.go:55–67

Write writes a "PID file" at the specified path. It returns an error if the file exists and contains a valid PID of a running process, or when failing to write the file.

(path string, pid int)

// file exists and contains a valid PID of a running process, or when failing
// to write the file.
func Write(path string, pid int) error {
	if pid < 1 {
		return fmt.Errorf("invalid PID (%d): only positive PIDs are allowed", pid)
	}
	oldPID, err := Read(path)
	if err != nil && !os.IsNotExist(err) {
		return err
	}
	if oldPID != 0 {
		return fmt.Errorf("process with PID %d is still running", oldPID)
	}
	return os.WriteFile(path, []byte(strconv.Itoa(pid)), 0o644)
}