I am confused because i thought that f is a future.
val f = (mybatchReader ? Read( "something" ) ).mapTo[Option[String]]
f.onComplete{
case SUCCESS =>
println( "Got x" )
But I am returning a non-future
val x:String = someFunctionThatThrowsAnException()
orig_sender ! x
Or is there something magical about the ask that makes whatever the
receiver is doing with the message into a Future?
On Tuesday, December 9, 2014 3:26:54 PM UTC-5, √ wrote:
>
> Could you elaborate on the question, I'm not sure I understand what you
> mean?
>
> On Tue, Dec 9, 2014 at 9:21 PM, David <[email protected] <javascript:>>
> wrote:
>
> Thanks Victor, Ryan for helping to clear up some fundamental understanding
> of mine.
>
> Can you please tell me why this works?
>
> This ditches the Future.
>
> The Driver does an Ask to MyBatchReader, which expects a future but
> MyBatchReader returns a non-Future.
>
> class MyDriver extends Actor{
>
> implicit val timeout = Timeout( 1.second )
>
> def receive = {
> case _ =>
> val f = (mybatchReader ? Read( "something" )
> ).mapTo[Option[String]]
> f.onComplete{
> case Success( result:Option[String] ) =>
> result match {
> case Some( data:String ) =>
> println( "Got result" )
> case None =>
> println( "Got no result" )
> }
>
> case Failure(e) =>
> println( "Sendee future failed" )
> e.printStackTrace()
>
> }
> }
>
> }
>
> class MyBatchReader extends Actor{
> def receive = {
> case Read(id) =>
> val orig_sender = sender()
> val x:String = someFunctionThatThrowsAnException()
> // triggers parent supervisor
> orig_sender ! x
> println("Sent future to Sender" )
> case _ => println( "Unknown" )
> }
>
>
>
>
>
>
> On Tuesday, December 9, 2014 2:25:50 PM UTC-5, Ryan Tanner wrote:
>
> As you can see, futures have their own form of error handling. The
> behavior you're seeing is exactly what's supposed to happen. Futures can
> be used completely independently of actors so if you want failed futures to
> trigger Akka's supervision, you'll need to do so yourself. In this case,
> if you really are just wrapped blocking functions up in futures within
> actors, I would ditch the futures entirely as they're only adding
> complexity.
>
> If you want an actor to restart if a failure it creates fails, you should
> send the failure message back to the actor itself and then let it re-throw
> the exception.
>
>
>
> On Tuesday, December 9, 2014 12:11:53 PM UTC-7, David wrote:
>
> Question in a nutshell:
> My Akka Actor creates a Future using the macro Future{someBlockingCall}
> within it's receive method.
> Inside someBlockingCall, I throw an exception. This does not trigger a
> supervisor in the parent. How can get the future to trigger a parent
> supervisor restart?
>
>
> In MyBatchReader, I have tested two places to throw exceptions:
>
> class MyBatchReader extends Actor{
> def receive = {
> case Read(id) =>
> val orig_sender = sender()
>
> //val s = someFunctionThatThrowsAnException()
> // Does trigger parent supervisor
>
> val f:Future[Option[String]] = Future{
>
> someFunctionThatThrowsAnException() // Does
> NOT trigger parent supervisor
>
> }
>
> f pipeTo orig_sender
> //orig_sender ! s
>
> println("Sent future to Sender" )
>
> case _ => println( "Unknown" )
> }
>
>
>
> The caller of MyBatchReaderActor:
>
> class MyDriver extends Actor{
>
> implicit val timeout = Timeout( 1.second )
>
> def receive = {
> case _ =>
> val f = (mybatchReader ? Read( "something" )
> ).mapTo[Option[String]]
> f.onComplete{
> case Success( result:Option[String] ) =>
> result match {
> case Some( data:String ) =>
> println( "Got result" )
> case None =>
> println( "Got no result" )
> }
>
> case Failure(e) =>
> println( "Sendee future failed" )
> e.printStackTrace()
>
> }
> }
> }
>
>
>
> So, MyDriver does a "?" on MyBatchReader which then itself creates a
> Future using Future{} macro.
>
> Is this incorrect code?
>
> In the above code, what I am seeing is the exception thrown, the future
> completing with FAILURE( "Sendee future failed" ), but the parent *NOT*
> executing a restart.
>
> If I change MyBatchReader to be (removing the macro creation of another
> future):
>
> class MyBatchReader extends Actor{
> def receive = {
> case Read(id) =>
> val orig_sender = sender()
> val x:String = someFunctionThatThrowsAnException()
> // triggers parent supervisor
> orig_sender ! x
> println("Sent future to Sender" )
> case _ => println( "Unknown" )
> }
>
>
> this works (trigger parent supervision) BUT I don't see how this can work
> since the sender is expecting a future back but MyBatchReader is returning
> a string.
> Or does the ask "?" in MyDriver automatically create a future? (Even when
> I use ! instead of pipeTo in MyBatchReader, MyDrive
>
> ...
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