code: func resolve(client *sshClient, network string, service string, port int) (string, error) {
  	// Inspect the service to get various configurations from it
  	infos, err := inspectContainer(client, fmt.Sprintf("%s_%s_1", network, service))
  	if err != nil {
  		return "", err
  	}
  	if !infos.running {
  		return "", ErrServiceOffline
  	}
  	// Container online, extract any environmental variables
  	if vhost := infos.envvars["VIRTUAL_HOST"]; vhost != "" {
  		return vhost, nil
  	}
  	return fmt.Sprintf("%s:%d", client.server, port), nil
  }
docs: // resolve retrieves the hostname a service is running on either by returning the
  // actual server name and port, or preferably an nginx virtual host if available.