How to get first or guardian actor in akka.net? - akka.net

Question

Edit : Executive summary: Where the bleep is 'Sys' defined? I see it in Akka.net code all over the internet, but my build is not finding it. Who or what do I have to import, use, link, do, bribe or kill?
Should be screamingly easy. Taking first steps in Akka.net, the sample does not build. This was copied from the [Getting Started example][1]
[1]: https://getakka.net/articles/intro/tutorial-1.html . It does not build, because 'Sys' is not defined. This obviously elementary step is nowhere described on their site, and I've given up on tweak-n-try.
Here is all of the code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace MyAkka
{
class Program
{
public class PrintMyActorRefActor : UntypedActor
{
protected override void OnReceive(object message)
{
switch (message)
{
case "printit":
IActorRef secondRef = Context.ActorOf(Props.Empty, "second-actor");
Console.WriteLine($"Second: {secondRef}");
break;
}
}
}
static void Main(string[] args)
{
Console.WriteLine("Hello World!");
var firstRef = Sys.ActorOf(Props.Create<PrintMyActorRefActor>(), "first-actor");
Console.WriteLine($"First: {firstRef}");
firstRef.Tell("printit", ActorRefs.NoSender);
Console.ReadKey();
}
}
}

Answer 1

Here is a working version of your code:
using System;
using Akka.Actor;
namespace SysInAkkaNet
{
class Program
{
public class PrintMyActorRefActor : UntypedActor
{
protected override void OnReceive(object message)
{
switch (message)
{
case "printit":
IActorRef secondRef = Context.ActorOf(Props.Empty, "second-actor");
Console.WriteLine($"Second: {secondRef}");
break;
}
}
}
static void Main(string[] args)
{
Console.WriteLine("Hello World!");
using (var actorSystem = ActorSystem.Create("MyActorSystem"))
{
var firstRef = actorSystem.ActorOf(Props.Create<PrintMyActorRefActor>(), "first-actor");
Console.WriteLine($"First: {firstRef}");
firstRef.Tell("printit", ActorRefs.NoSender);
Console.ReadKey();
}
}
}
}
You need to create an actor system to put your actors in. And you need to add a reference to the Akka NuGet package, and a corresponding using Akka.Actor; statement.
I know that the Akka.TestKit has a property Sys, which gives you a reference to the actor system that is created for a given test.
Apart from that, I am not able to answer why the documentation you are referring to shows these "Sys.ActorOf(...)" examples like that (with a capital S), indicating that it is a (possibly built-in) property, so I kind of understand your confusion there.