Future with timeout

future_timeout.scala

scala> :paste
// Entering paste mode (ctrl-D to finish)

import scala.concurrent._
import scala.concurrent.duration._
import ExecutionContext.Implicits.global
import akka.actor._
import akka.pattern.after

implicit class FutureWithTimeout[A](f: Future[A]) {
  def withTimeout(duration: FiniteDuration)(implicit system: ActorSystem): Future[A] = 
    Future.firstCompletedOf(Seq(f, after(duration, system.scheduler)(Future.failed(new TimeoutException("Future timed out!")))))
}

// Demo!
implicit val sys = ActorSystem("sys")
val future = Future(Thread.sleep(1000*60*60*24*365)) // 1 year
Await.result(future.withTimeout(5 seconds), 365 days)

// Exiting paste mode, now interpreting.

java.util.concurrent.TimeoutException: Future timed out!
  at FutureWithTimeout$$anonfun$withTimeout$1.apply(<console>:19)
  at FutureWithTimeout$$anonfun$withTimeout$1.apply(<console>:19)
  at akka.pattern.FutureTimeoutSupport$$anonfun$after$1.liftedTree1$1(FutureTimeoutSupport.scala:23)
  at akka.pattern.FutureTimeoutSupport$$anonfun$after$1.apply$mcV$sp(FutureTimeoutSupport.scala:23)
  at akka.actor.Scheduler$$anon$7.run(Scheduler.scala:117)
  at scala.concurrent.impl.ExecutionContextImpl$AdaptedForkJoinTask.exec(ExecutionContextImpl.scala:121)
  at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
  at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
  at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
  at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)