以编程方式创建远程参与者不起作用

Question

我正在以编程方式创建远程 akka actor。

下面是程序-

package remoting.programatic.demo

import akka.actor.{ActorSystem, Props}
import com.typesafe.config.ConfigFactory
import remoting.config.demo.RemoteActor

object RemoteActorApp extends App {

  val system = ActorSystem("RemoteNodeApp", ConfigFactory.load().getConfig("RemoteProgrammatically"))
  val remoteActor = system.actorOf(Props[RemoteActor], name = "remoteActorAddr")

  remoteActor ! "Hello!"

  val actorSelection = system.actorSelection("akka.tcp://RemoteNodeApp@localhost:2553/user/remoteActorAddr")
  Thread.sleep(4000L)

  actorSelection ! "Hello!"

}

配置为 -

RemoteProgrammatically {
  akka {
    actor {
      provider = "akka.remote.RemoteActorRefProvider"
      deployment {
        /remoteActorAddr {
          remote = "akka.tcp://RemoteNodeApp@localhost:2553"
        }
      }
    }
    remote {
      enabled-transports = ["akka.remote.netty.tcp"]
      netty.tcp {
        hostname = "localhost"
        port = 2553
      }
    }
  }
}

运行程序后的输出是 -

[INFO] [12/27/2017 10:37:30.053] [main] [akka.remote.Remoting] Starting remoting
[INFO] [12/27/2017 10:37:30.378] [main] [akka.remote.Remoting] Remoting started; listening on addresses :[akka.tcp://RemoteNodeApp@localhost:2553]
[INFO] [12/27/2017 10:37:30.379] [main] [akka.remote.Remoting] Remoting now listens on addresses: [akka.tcp://RemoteNodeApp@localhost:2553]
[INFO] [12/27/2017 10:37:30.418] [RemoteNodeApp-akka.actor.default-dispatcher-14] [akka://RemoteNodeApp/deadLetters] Message [java.lang.String] from Actor[akka://RemoteNodeApp/user/remoteActorAddr#-766312407] to Actor[akka://RemoteNodeApp/deadLetters] 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'.
[INFO] [12/27/2017 10:37:34.419] [RemoteNodeApp-akka.actor.default-dispatcher-14] [akka://RemoteNodeApp/deadLetters] Message [java.lang.String] from Actor[akka://RemoteNodeApp/user/remoteActorAddr#-766312407] to Actor[akka://RemoteNodeApp/deadLetters] was not delivered. [2] 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'.

我发给演员的消息总是进入死信。看起来 remoteActorAddr 没有在 RemoteNodeApp actor 系统中成功创建。知道为什么没有创建演员以及为什么消息总是变成死信。谢谢

Answer 1

Message [java.lang.String] from Actor[akka://RemoteNodeApp/user/remoteActorAddr#-766312407] to Actor[akka://RemoteNodeApp/deadLetters] was not delivered. [1] dead letters encountered.

上面从您的日志中摘录的内容表明，在从远程参与者发送字符串消息时遇到死信邮箱。远程 actor 显然正在向 sender() 发送消息，在这种情况下这是死信，因为远程 actor 收到的消息是从 actor 外部使用 tell (!) 发送的。也就是说，远程actor是创建成功，但是下面两条消息是非actor发送的，导致远程actor中的sender()解析为死信:

remoteActor ! "Hello!" ... actorSelection ! "Hello!"

来自 documentation（强调我的）：

actorRef ! message

If invoked from within an Actor, then the sending actor reference will be implicitly passed along with the message and available to the receiving Actor in its sender(): ActorRef member method. The target actor can use this to reply to the original sender, by using sender() ! replyMsg.

If invoked from an instance that is not an Actor the sender will be deadLetters actor reference by default.

从另一个 actor 发送消息，或使用 ask 模式（创建一个内部 actor 来处理回复）。

以编程方式创建远程参与者不起作用

Creating Remote Actors Programmatically is not working

scala

akka

akka-remote-actor

akka-remoting