Akka 广播请求不会传递给所有路由

Question

我正在学习在 Akka 路由器中使用广播消息。有没有办法从所有路由到路由器接收 ask 的响应？

我有这个示例代码。

Master.scala

object Master {
    case object brdcst
}

class Master extends Actor {
    implicit val timeout = Timeout(5 seconds)

    val router: ActorRef = context.actorOf (RoundRobinPool (3).props(Props[Worker]), "router")

    override def receive: Receive = {
        case brdcst => {
            val future = router ? Broadcast(brdcst)
            val result = Await.result(future, timeout.duration)
            println("result = " + result)
        }
    }
}

object MasterTest extends App {
    val actorSystem = ActorSystem("ActorSystem")
    val actor = actorSystem.actorOf(Props[master], "root")
    actor ! brdcst
}

Worker.scala

class Worker extends Actor {
    val routee = context.actorOf(Props[Worker], "routee")

    override def receive: Receive = {
        case brdcst => sender() ! self.path.name
    }
}

此代码给出以下输出

result = $a
[INFO] [10/16/2018 21:47:07.484] [ActorSystem-akka.actor.default-dispatcher-2] [akka://ActorSystem/deadLetters] Message [java.lang.String] from Actor[akka://ActorSystem/user/root/router/$a#340358688] to Actor[akka://ActorSystem/deadLetters] was not delivered. [1] dead letters encountered. If this is not an expected behavior, then [Actor[akka://ActorSystem/deadLetters]] may have terminated unexpectedly, This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.
[INFO] [10/16/2018 21:47:07.504] [ActorSystem-akka.actor.default-dispatcher-10] [akka://ActorSystem/deadLetters] Message [java.lang.String] from Actor[akka://ActorSystem/user/root/router/$b#-151225340] to Actor[akka://ActorSystem/deadLetters] was not delivered. [2] dead letters encountered. If this is not an expected behavior, then [Actor[akka://ActorSystem/deadLetters]] may have terminated unexpectedly, This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.

所以回复仅来自一个路由。如何获得所有路由的响应？（也许像 result = [$a, $b, $c] 这样的列表）

Answer 1

ask (?) 创建一个内部参与者来处理回复。这个内部 actor 只处理一个回复并自动关闭：这就是你只得到第一个回复，而其他两个路由的回复变成死信的原因。

要获得所需的行为，请使用 tell (!) 并收集路由的响应。例如：

class Master extends Actor {
  val numRoutees = 3
  val router = context.actorOf(RoundRobinPool(numRoutees).props(Props[Worker]), "router")

  def handleMessages(replies: Set[String] = Set()): Receive = {
    case brdcst =>
      router ! Broadcast(brdcst)
    case reply: String =>
      val updatedReplies = replies + reply
      if (updatedReplies.size == numRoutees) {
        println("result = " + updatedReplies.mkString("[", ",", "]"))
      }
      become(handleMessages(updatedReplies))
  }

  def receive = handleMessages
}

在上面的示例中，master 使用 become.

将 routees 的回复编码为其状态的一部分

另外，不要在 actors 中使用 Await。

Akka 广播请求不会传递给所有路由

Akka broadcast ask doesn't deliver to all routees

scala

broadcast

akka