How to wait for Akka actor system to terminate?

Question

I need to start Akka (2.0) actor system, send in some messages, then wait for it to do heavy lifting. After that, I need to do something unrelated to those actors.

I

Answer 1

Just a side note for those running into this question for its title: Apparently, Akka 2.5 does not support actorSystem.awaitTermination anymore. Reason being why might be Akka's philosophy of avoiding any blocking calls. Instead, actorSystem.registerOnTermination(...) can be used as a non-blocking way to do actions while an ActorSystem is being shutdown.

Nonetheless, you can still wait for your actor system to complete via a Future provided by ActorSystem.whenTerminated:

val system = new ActorSystem("parallelRunners")
val master = system.actorOf(Props[Master])
master ! Start

import scala.concurrent.Await
import scala.concurrent.duration._
Await.ready(system.whenTerminated, 365.days)