Akka Streams 中的 RestartFlow 未按预期工作

Question

我正在使用 Akka Streams 的 Delayed restarts with backoff stage 功能，它似乎对我不起作用。

我的测试代码是：

object Test {
  import akka.stream.scaladsl.{ Flow, RestartFlow, Sink, Source }
  import scala.concurrent.duration._
  import akka.actor.ActorSystem
  import akka.stream.ActorMaterializer

  implicit val actorSystem = ActorSystem()
  implicit val mat = ActorMaterializer()

  def main(args: Array[String]): Unit = {
    val source = Source(1 to 10)
    val flow = Flow[Int].map { x =>
      println(s"Processing: $x")
      if (x != 6) {
        x * 2
      } else throw new RuntimeException("Baam!!")
    }
    val restartFlow = RestartFlow.onFailuresWithBackoff(10.milliseconds, 20.milliseconds, 0.2, 3)(() => flow)
    source.via(restartFlow).to(Sink.ignore).run()
  }
}

我预计异常会发生三次，因为最大重启次数等于 3。但是，相反，我只看到一次异常。我在这里错过了什么？

运行它的输出：

Processing: 1
Processing: 2
Processing: 3
Processing: 4
Processing: 5
Processing: 6
[ERROR] [03/20/2018 16:13:59.167] [default-akka.actor.default-dispatcher-2] [RestartWithBackoffFlow(akka://default)] Restarting graph due to failure
java.lang.RuntimeException: Baam!!
    at Test$.$anonfun$main(Test.scala:18)
    at scala.runtime.java8.JFunction1$mcII$sp.apply(JFunction1$mcII$sp.java:12)
    at akka.stream.impl.fusing.Map$$anon.onPush(Ops.scala:53)
    at akka.stream.impl.fusing.GraphInterpreter.processPush(GraphInterpreter.scala:519)
    at akka.stream.impl.fusing.GraphInterpreter.processEvent(GraphInterpreter.scala:482)
    at akka.stream.impl.fusing.GraphInterpreter.execute(GraphInterpreter.scala:378)
    at akka.stream.impl.fusing.GraphInterpreterShell.runBatch(ActorGraphInterpreter.scala:585)
    at akka.stream.impl.fusing.GraphInterpreterShell$AsyncInput.execute(ActorGraphInterpreter.scala:469)
    at akka.stream.impl.fusing.GraphInterpreterShell.processEvent(ActorGraphInterpreter.scala:560)
    at akka.stream.impl.fusing.ActorGraphInterpreter.akka$stream$impl$fusing$ActorGraphInterpreter$$processEvent(ActorGraphInterpreter.scala:742)
    at akka.stream.impl.fusing.ActorGraphInterpreter.akka$stream$impl$fusing$ActorGraphInterpreter$$shortCircuitBatch(ActorGraphInterpreter.scala:732)
    at akka.stream.impl.fusing.ActorGraphInterpreter.preStart(ActorGraphInterpreter.scala:726)
    at akka.actor.Actor.aroundPreStart(Actor.scala:528)
    at akka.actor.Actor.aroundPreStart$(Actor.scala:528)
    at akka.stream.impl.fusing.ActorGraphInterpreter.aroundPreStart(ActorGraphInterpreter.scala:667)
    at akka.actor.ActorCell.create(ActorCell.scala:654)
    at akka.actor.ActorCell.invokeAll(ActorCell.scala:525)
    at akka.actor.ActorCell.systemInvoke(ActorCell.scala:547)
    at akka.dispatch.Mailbox.processAllSystemMessages(Mailbox.scala:282)
    at akka.dispatch.Mailbox.run(Mailbox.scala:223)
    at akka.dispatch.Mailbox.exec(Mailbox.scala:234)
    at akka.dispatch.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
    at akka.dispatch.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
    at akka.dispatch.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
    at akka.dispatch.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)

Answer 1

您遇到了一个已报告的问题：https://github.com/akka/akka/issues/24726

更新：此问题已在 Akka 2.5.13 补丁版本中修复。

Akka Streams 中的 RestartFlow 未按预期工作

RestartFlow in Akka Streams not working as expected

scala

akka

akka-stream