akka 演员：Patterns.pipe 代表 Either

Question

我有这样的方法：

def myFuture: Future[Either[MyLeft, MyRight]] = Future {
.
.
.
}

如果我想通过管道传输结果，我使用：

Patterns.pipe(myFuture,ec).to(destinationActor)

但我想在 Left 的情况下将结果发送给一个演员，在 Right 的情况下将结果发送给另一个演员。像这样的伪代码：

MyPatterns.eitherPipe(myFuture,ec).to(leftConsumerActor,rightConsumerActor)

Answer 1

如果你这样做了？

myFuture onComplete {
   case Success(s) => s match {
      case Right(r) => rightConsumerActor ! r 
      case Left(l) =>  leftConsumerActor ! l
  }
   case Failure(f) => println("failure")
}

Answer 2

akka的源代码本身就是一个很好的提示应该做什么。看看 akka.pattern.PipeToSupport:

def pipeTo(recipient: ActorRef)(implicit sender: ActorRef = Actor.noSender): Future[T] = {
  future andThen {
    case Success(r) ⇒ recipient ! r
    case Failure(f) ⇒ recipient ! Status.Failure(f)
  }
}

所以我们基本上可以通过调度 Either:

在我们的案例中重用这种方法

val result: Future[Either[Int, Throwable]] = Future.successful(Left(5))
result andThen {
  case Success(Left(value)) => leftActor ! value
  case Success(Right(exception)) => rightActor ! exception
  case Failure(exception) => println("Failure")
}

实现所需的 DSL：

我们可以像这样尝试实现您的 DSL(eitherPipe() 和 to(...)):

trait MyEitherPipeSupport extends PipeToSupport {

    final class PipeableEitherFuture[L, R](val future: Future[Either[L, R]])(implicit executionContext: ExecutionContext) {

      def to(leftRef: ActorRef, rightRef: ActorRef, exceptionRef: ActorRef) = future andThen {
        case Success(Left(value)) ⇒ leftRef ! value
        case Success(Right(exception)) ⇒ rightRef ! exception
        case Failure(exception) ⇒ exceptionRef ! Status.Failure(exception)
      }
    }

    implicit def eitherPipe[L, R](future: Future[Either[L, R]])(implicit executionContext: ExecutionContext): PipeableEitherFuture[L, R] = new PipeableEitherFuture(future)

  }

现在在你的演员中你只需混合 MyEitherPipeSupport 就可以这样写：

    val result: Future[Either[Int, Throwable]] = Future.successful(Left(5))
    eitherPipe(result).to(left, right, anotherOne)

akka 演员：Patterns.pipe 代表 Either

akka actor: Patterns.pipe for Either

design-patterns

scala

actor

akka