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scalaakkaakka-streamakka-supervision

Supervision.decider strategy in akka 2.6.0

I have to pass supervision.decider but in akka 2.6.0+ Materializer does not have similar settings.

Can anyone share how to write below code in higher version:

val mat: ActorMaterializer = ActorMaterializer(Actor Materializersettings(supervision.decider))

Tried new way, not picking as strategy class requires String:

1.

val mat: Materializer = Matrializer(actorsystem)
mat.system.settings.supervisionstratgyclass = ???
  1. ActorAttributes(supervision.decider)

Any idea would be appreciated how to pass supervision strategy through materializer.

How we pass custom supervision strategy in settings? I don't use streams. It will simple startup call with materializer.

Solution

  • Sounds like you want to setup a supervision strategy for a stream. Here you have some examples of how to do it from the official documentation: Stream error - supervision strategies.

    As you can see, in the following example a default supervision strategy is being set for the runnable graph

    val decider: Supervision.Decider = {
  case _: ArithmeticException => Supervision.Resume
  case _                      => Supervision.Stop
}
val source = Source(0 to 5).map(100 / _)
val runnableGraph =
  source.toMat(Sink.fold(0)(_ + _))(Keep.right)

val withCustomSupervision = runnableGraph.withAttributes(ActorAttributes.supervisionStrategy(decider))

    In this other one, a supervision strategy is being defined at Flow level

    val decider: Supervision.Decider = {
  case _: ArithmeticException => Supervision.Resume
  case _                      => Supervision.Stop
}
val flow = Flow[Int]
  .filter(100 / _ < 50)
  .map(elem => 100 / (5 - elem))
  .withAttributes(ActorAttributes.supervisionStrategy(decider))
val source = Source(0 to 5).via(flow)