Pigeon – Akka Actors for .NET

I’m working on a port of the Java/Scala framework Akka, or rather the Actor Model part of it.
As of now, this is only a bit more than a weekend hack, so don’t expect too much.
But I already have a couple of nice features in:

Git hub repository goes here: https://github.com/rogeralsing/Pigeon

Write your first actor:

public class Greet : IMessage
{
    public string Who { get; set; }
}

public class GreetingActor : UntypedActor
{
    protected override void OnReceive(IMessage message)
    {
        message.Match()
            .With(m => Console.WriteLine("Hello {0}", m.Who));
    }
}

Usage:

var system = new ActorSystem();
var greeter = system.ActorOf("greeter");
greeter.Tell(new Greet { Who = "Roger" }, ActorRef.NoSender);

Remoting support:

//Server Program.CS
var system = ActorSystemSignalR.Create("myserver", "http://localhost:8080);
var greeter = system.ActorOf("greeter");
Console.ReadLine();

//Client Program.CS
var system = new ActorSystem();
var greeter = system.ActorSelection("http://localhost:8080/greeter");
//pass a message to the remote actor
greeter.Tell(new Greet { Who = "Roger" }, ActorRef.NoSender);

There are still alot of things that needs to be implemented/fixed.
Actor paths don’t work correctly at the momeent for example.
Supervision and other features are missing etc.

One nice feature I managed to squeeze in was “Futures”.
Futures in Akka is pretty much Task of T in .NET.
However, Futures in Akka is synchronous and you need to (bussy) wait for them to complete.
[edit]
As Alexey Romanov pointed out in the comments, this is not true.
You can get async futures using either onComplete callbacks,
or using Scala async support https://github.com/scala/async and use async/await.

In Pigeon however, we have Async/Await support.

You can async await responses from other actors like this:


//inside an actor
var result = await Ask(someActor, messageToAsk);
result.Match()
    .With(m => {
         Console.WriteLine("got awaited result {0}",m);
    })
    .Default(_ => Console.WriteLine("Unknown message"));

The nice thing is that the await continuation will execute in the actor context, so there is no threading issues inside the actor here.

Hope you like it :)

5 thoughts on “Pigeon – Akka Actors for .NET”

  1. @Alexey
    Ah sweet, thanks for the clarification.
    Using the onComplete approach, I take it that that part is available to the Java API too?
    There is alot of talk about blocking futures in the material I’ve been reading, is the scala async support new’ish?

    1. > Using the onComplete approach, I take it that that part is available to the Java API too?

      Of course, see examples in http://doc.akka.io/docs/akka/2.2.0/java/futures.html.

      > There is alot of talk about blocking futures in the material I’ve been reading, is the scala async support new’ish?

      While async support is new’ish (and not yet stable: the current version is a milestone), onComplete and combinators have been core part of Akka Futures (and other Scala Future libraries, before they unified) for a long time.

      Might your materials be confusing them with the standard Java library futures (which _do_ need blocking)?

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