add WatchAysnc methods for monitoring actor lifecycles outside of Akka.NET
#6102
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| @@ -1882,6 +1882,10 @@ namespace Akka.Actor | |||
| public Akka.Actor.IStash Stash { get; set; } | |||
| } | |||
| public delegate void UntypedReceive(object message); | |||
| public class static WatchAsyncSupport | |||
| { | |||
| public static System.Threading.Tasks.Task<bool> WatchAsync(this Akka.Actor.IActorRef target, System.Threading.CancellationToken token = null) { } | |||
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Just a new extension method for working with IActorRef
| @@ -51,7 +51,7 @@ public async Task GracefulStopShouldReturnTrueForAlreadyDeadActor() | |||
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| private class CustomShutdown{} | |||
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| [Fact(DisplayName = "GracefulStop should return false if shutdown goes overtime", Skip = "GracefulStop currently throws a TaskCancellationException, which seems wrong")] | |||
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Enabled this spec as I went back and addressed this behavior
| public class WatchAsyncSpecs : AkkaSpec | ||
| { | ||
| [Fact(DisplayName = "WatchAsync should return true when actor is terminated")] | ||
| public async Task WatchAsync_should_return_true_when_actor_is_terminated() |
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Happy path use case test.
| } | ||
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| [Fact(DisplayName = "WatchAsync should return true when called on actor that is already terminated")] | ||
| public async Task WatchAsync_should_return_true_when_actor_is_already_terminated() |
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Idempotent use case - watching an already dead actor.
| } | ||
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| [Fact(DisplayName = "WatchAsync should return false when cancellation token is cancelled")] | ||
| public async Task WatchAsync_should_return_true_when_cancelled() |
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Negative case - cancellation.
| { | ||
| var dw = message as DeathWatchNotification; |
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pattern matching refactoring
| { | ||
| //TODO: find a way to get access to logger? | ||
| Console.WriteLine("BUG: illegal Watch({0},{1}) for {2}", watch.Watchee, watch.Watcher, this); | ||
| if (!AddWatcher(watch.Watcher)) |
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More automatic refactoring
| var unwatch = message as Unwatch; | ||
| if (Equals(unwatch.Watchee, this) && !Equals(unwatch.Watcher, this)) RemoveWatcher(unwatch.Watcher); | ||
| else Console.WriteLine("BUG: illegal Unwatch({0},{1}) for {2}", unwatch.Watchee, unwatch.Watcher, this); | ||
| case Unwatch unwatch when Equals(unwatch.Watchee, this) && !Equals(unwatch.Watcher, this): |
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Automatic refactoring
| } | ||
| catch | ||
| { | ||
| // no need to throw here - the returned `false` status does the job just fine |
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Behavioral change for GracefulStop - no longer throws TaskCancelledExceptions when cancelled. Why? Because returning false does this in a much more easily handleable way. The exception adds no value.
| /// <param name="token">Optional - a cancellation token.</param> | ||
| /// <returns><c>true</c> if the target was terminated, <c>false</c> otherwise.</returns> | ||
| /// <exception cref="InvalidOperationException">Thrown if we attempt to watch a</exception> | ||
| public static async Task<bool> WatchAsync(this IActorRef target, CancellationToken token = default) |
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After I refactored the guts of PromiseActorRef implementing WatchAsync was pretty easy to implement - it's just the GracefulStop code but without sending a kill message to the actor and it uses CancellationToken instead of a TimeSpan. That's all.
Aaronontheweb
changed the title
WatchAysnc methodsWatchAysnc methods for monitoring actor lifecycles outside of Akka.NET
Changes
Prototyping a method to death watch an
IActorReffrom outside theActorSystem.Checklist
For significant changes, please ensure that the following have been completed (delete if not relevant):
Documentation
I'll need to add a whole page on "working with actors outside Akka.NET" - this will get featured there. That'll also talk about Ask, GracefulStop, and so on.