DeadLetters with Router/ActorSelection with remote routees

[Pierre Falda]

Hi everyone,

I set up a little testing environment to debug another problem with remoting, but I'm stuck on an issue (?) with actorselection: telling a message to a remotely created router works, telling the message to an actorselectopn of that router, routes the message to deadletters.

Akka version: 2.3.3

(At the end of the mail, the application.conf)

My test code:

public class Main {

    public static void main(String[] args) throws InterruptedException {

        ActorSystem test_system = akka.actor.ActorSystem.create("PingActorSystem");

        test_system.eventStream().subscribe(test_system.actorOf(Props.create(EventWatcher.class)),Object.class);

        ActorRef router = test_system.actorOf(Props.create(LocalRouter.class).withRouter(new FromConfig()),"LocalRouter");

        ActorSelection router_selection = test_system.actorSelection("akka.tcp://PingAct...@192.168.2.17:2553/LocalRouter");

        Thread.sleep(1000);

        System.err.println(String.format("Selection ActorPath: %s AnchorPath: %s",router_selection.pathString(),router_selection.anchorPath()));

        router.tell(new Integer(1234),ActorRef.noSender());

        router_selection.tell("PING!?!?",ActorRef.noSender());

    }

}

The Output:

[INFO] [07/11/2014 12:35:43.352] [main] [Remoting] Starting remoting

[INFO] [07/11/2014 12:35:43.507] [main] [Remoting] Remoting started; listening on addresses :[akka.tcp://PingAct...@192.168.2.17:2553]

[INFO] [07/11/2014 12:35:43.508] [main] [Remoting] Remoting now listens on addresses: [akka.tcp://PingAct...@192.168.2.17:2553]

Received: akka.remote.AssociatedEvent

Selection ActorPath: /LocalRouter AnchorPath: akka://PingActorSystem/

Received: akka.actor.DeadLetter

java.lang.String

Received: akka.event.Logging$Info

[INFO] [07/11/2014 12:35:44.540] [PingActorSystem-akka.actor.default-dispatcher-4] [akka://PingActorSystem/LocalRouter] Message [java.lang.String] from Actor[akka://PingActorSystem/deadLetters] to Actor[akka://PingActorSystem/LocalRouter] was not delivered. [1] dead letters encountered. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.

The remote routees are successfully created and are not dead. I have no log at all on the worker/routees console (PongActorSystem), except for the receive of the numeric message.

Then I tried to ActorSelect the router from a third machine, but I have the same behaviour: message are correctly sent to the remote router (PingActoSystem), but instead

of forwarding it to the remotely deployed routees ( target {  nodes = ["akka.tcp://PongAct...@192.168.2.17:2552"] } ) it routes the message to deadletters.

Does anyone have ever had a similar issue? How could I fix?

Thanks in advance

- Pierre

Configuration:

akka {

  loglevel = "INFO"

  stdout-loglevel = "INFO"

  actor {

    provider = "akka.remote.RemoteActorRefProvider"

    serialize-creators = on

    serialize-messages = on

    serializers {

      java = "akka.serialization.JavaSerializer"

      proto = "akka.remote.serialization.ProtobufSerializer"

    }

    serialization-bindings {

      "java.lang.String" = java

      "com.google.protobuf.Message" = proto

    }

    deployment {

      /LocalRouter {

        target {

          nodes = ["akka.tcp://PongAct...@192.168.2.17:2552"]

        }

        router = balancing-pool

        nr-of-instances = 1

      }

    }

    default-dispatcher {

      throughput = 10

      executor = "fork-join-executor"

    }

  }

  remote {

    enabled-transports = ["akka.remote.netty.tcp"]

    hostname = "Vortex"

    netty.tcp.port = 2553

  }

}

[Martynas Mickevičius]

Hi Pierre,

router itself is not an actor. It is an optimized ActorRef which sends messages directly to the routees. Therefore you can't select router with ActorSelection. However you can select individual children with ActorSelection which has names c1, c2, ...:

ActorSelection router_selection = test_system.actorSelection("akka.tcp://PingActorSystem@192.168.2.17:2553/LocalRouter/c1");

But that is not very useful.

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[Martynas Mickevičius]

Also I just noticed an error in your configuration. Instead:

remote {

    enabled-transports = ["akka.remote.netty.tcp"]

    hostname = "Vortex"

    netty.tcp.port = 2553

}

it should be

remote {

    enabled-transports = ["akka.remote.netty.tcp"]

    netty.tcp {

        hostname = "Vortex"

        port = 2553

    }

}

[Pierre Falda]

Hi Martynas,

I think I found the problem reviewing some old code: I must specify /user in the actoselection path:

ActorSelection router_selection = test_system.actorSelection("akka.tcp://PingAct...@192.168.2.17:2553/user/LocalRouter");

Doing in this way works, but is this a bad pratice since (or at least is seems that) I'm actorselecting a remote router?

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[Pierre Falda]

Hi Martynas Mickevičius,

thank you, this fixed the connection problem with the hostname that I reported in the other thread! :-)

Pierre

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-- 
Pierre Falda
Technical Manager
DisBrain s.r.l.
www.disbrain.com