Calling Akka actor from Play controller

Question

I have been playing with the distributed worker pattern and I'm running into an issue pushing work from a web request.

The example project has a frontend:

val mediator = DistributedPubSubExtension(context.system).mediator

  def receive = {
    case work =>
      log.info("Frontend received: " + work.toString())
      implicit val timeout = Timeout(5.seconds)
      (mediator ? Send("/user/master/active", work, localAffinity = false)) map {
        case Master.Ack(_) => Ok
      } recover { case _ => NotOk } pipeTo sender
  }

And a WorkProducer:

override def preStart(): Unit =
    scheduler.scheduleOnce(5.seconds, self, Tick)

def receive = {
    case Tick =>
      n += 1
      log.info("Produced work: {}", n)
      val work = Work(nextWorkId(), n)
      frontend ! work
      context.become(waitAccepted(work), discardOld = false)

  }

This all works just fine, when I send directly to the frontend from my Play Framework controller:

def multiply(num: Long) = Action {
    implicit request =>
        implicit val timeout = Timeout(5.seconds)
        val frontend = core.Main.frontend
        frontend ! num
        Ok
  }

The message seems to get lost. The frontend receives the message but it seems the actors down stream do not.

I have modified the play config to use a ClusterActorRefProvider

play {
  akka {
    extensions = ["akka.contrib.pattern.ClusterReceptionistExtension"]    
    actor.provider = "akka.cluster.ClusterActorRefProvider"
    remote.netty.tcp.port=0
        }
}

But to no avail.

score 0 · Accepted Answer · answered Jun 27 '14 at 16:00

I've been a muppet and haven't sent the correct message, the controller should look like this:

def multiply(num: Long) = Action {
    implicit request =>
        implicit val timeout = Timeout(5.seconds)
        val frontend = core.Main.frontend
        val work = Work(nextWorkId(), num)
        frontend ! work
        Ok
  }

Calling Akka actor from Play controller

1 Answers1