Akka akka / scala - single onSuccess for multiple requests

I have a chain of akka actors like

A --> B --> C


Actor A asks Actor B, who in turn "asks" Actor C. Actor A needs to wait until Actor C finishes processing. B is a thin layer and does nothing but send (request) a message to C and return the future back to A. Basically B just does

        { case msgFromA => sender ! C ? msgFromA }


Therefore, what A gets is the Future [Any].

The way to handle the request is to use nested maps

actorRefFactory.actorOf(Props[A]) ? msgA map {
        resp =>
          // Type cast Any to Future and use another map to complete processing. 
          resp.asInstanceOf[Future[_]] map {
            case Success =>
              // Complete processing
            case Failure(exc) =>
             // Log error


This works (i.e., final processing only occurs when the C actor has finished processing), but of course it looks terrible. I tried using flatmaps but couldn't get it to work. Any ideas to make it look good :) Thanks


source to share

1 answer

A more correct way:

In A


val f: Future[MyType] = (B ? msg).mapTo[MyType]
f onComplete {
  case Success(res) => // do something
  case Failure(t) => // do something


In B

use forward


{ case msgFromA => C forward msgFromA }


In C


// call database
// update cache
sender() ! res   // actually sends to A




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