code: func podPort(pod *corev1.Pod, annotation string, host bool) (int32, error) {
  	// First look for a matching port matching the value of the annotation.
  	for _, container := range pod.Spec.Containers {
  		for _, portDef := range container.Ports {
  			if portDef.Name == annotation {
  				if host {
  					// It is possible for HostPort to be zero, if that is the
  					// case then we ignore this port.
  					if portDef.HostPort == 0 {
  						continue
  					}
  
  					return portDef.HostPort, nil
  				}
  
  				return portDef.ContainerPort, nil
  			}
  		}
  	}
  
  	// Otherwise assume that the port is a numeric value.
  	v, err := strconv.ParseInt(annotation, 0, 32)
  	return int32(v), err
  }
docs: // podPort extracts the proper port for the address from the given pod
  // for a non-empty annotation.
  //
  // Pre-condition: annotation is non-empty