code: func parseUserFromImageUser(id string) string {
  	if id == "" {
  		return id
  	}
  	// split instances where the id may contain user:group
  	if strings.Contains(id, ":") {
  		return strings.Split(id, ":")[0]
  	}
  	// no group, just return the id
  	return id
  }
docs: // parseUserFromImageUser splits the user out of an user:group string.