带有macWire DI的Akka actoreRef，未设置actoreRef

Question

I have a 2 actors, Actor1 and Actor2 . Actor1 wants to send MyMsg1 to Actor2 , and Actor2 after doing some work and getting Future[MyMsg2] wants to send MyMsg2 to Actor1 . I have got this working one way but it fails with DI.

1. Scenario 1 - Working scenario

   • Actor1 -->MyMsg1-->Actor2
   • Actor2 MyMsgHandler - Processes message(with Future), does pipeTo to sender with MyMsg2 . Works fine, Actor1 recvs MyMsg2

2. Scenario2 - Failing scenario

   • Actor1 has a bean injected via MacWire - myBean .
   • myBean has Actor2 injected as a bean and sends MyMsg1 to Actor2
   • Actor2 MyMsgHandler processes message(with Future), does pipeTo to sender and tries sending MyMsg2 - Goes to deadLetter. The actor Ref for sender is never set.

How do I fix this?

Pasting code also

class Actor1(failedService: FailedService, actor2: ActorRef @@ Actor2) extends Actor{
  override def receive: Receive = {
    case TriggerActor1() =>
      println("Actor1 triggered from REST controller. Send msg to actor 2")
      failedService.testSend()
      //actor2 ! Msg1()
    case Msg2() => println("got msg2 from actor 1")
  }

class Actor2 extends Actor {
  override def receive: Receive = {
    case Msg1() => {
      println("send without future")
      val origsender = sender()
      origsender ! Msg2()
    }
  }

class FailedService(actor2: ActorRef@@Actor2) {
  def testSend() = {
    actor2 ! Msg1()
  }
}

With my current code as shared above, Actor1 is able to send Msg1 to Actor2 and actor2 responds with Msg2 but Msg2 goes to deadletter. I get the below error akka.actor.DeadLetterActorRef - Message [backup.failedakka.Msg2] from Actor[akka://application/user/actor2#-662746578] to Actor[akka://application/deadLetters] was not delivered. [1] dead letters encountered. akka.actor.DeadLetterActorRef - Message [backup.failedakka.Msg2] from Actor[akka://application/user/actor2#-662746578] to Actor[akka://application/deadLetters] was not delivered. [1] dead letters encountered.

However, if insted of using the line failedService.testSend() in my Actor1, I uncomment the line below it and use that to communicate, things work fine. Is the Q clear now? I am injecting dependencies with MacWire

Answer 1

! is defined as:

def !(message: Any)(implicit sender: ActorRef = Actor.noSender): Unit

You can see the problem now, there's no implicit sender in scope of FailedService , although it is in scope "inside" an actor implementation.

I think you want to do:

class FailedService(actor2: ActorRef@@Actor2) {
  def testSend(implicit sender: ActorRef) = {
    actor2 ! Msg1()
  }
}