code: func ReadHostUUID(dataDir string) (string, error) {
  	out, err := ReadPath(filepath.Join(dataDir, HostUUIDFile))
  	if err != nil {
  		return "", trace.Wrap(err)
  	}
  	return strings.TrimSpace(string(out)), nil
  }
docs: // ReadHostUUID reads host UUID from the file in the data dir