code: func svcOpt(cfg *conf.ConfigFile, service, option string, required bool) string {
  	// TODO(jsing): Add support for defaults.
  	opt := cfgOpt(cfg, service, option)
  	if opt == "" && required {
  		log.Fatalf("Service %s has missing %s option", service, option)
  	}
  	return opt
  }
docs: // svcOpt returns the specified configuration option for a service.