add GetAsync method to ActorRegistry
#33
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| /// <summary> | ||
| /// Used to implement "wait for actor" mechanics | ||
| /// </summary> | ||
| internal sealed class WaitForActorRegistration : IEquatable<WaitForActorRegistration> |
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Registration handle - we create one of these per-waiter.
| /// <remarks> | ||
| /// Have to store a collection of <see cref="WaitForActorRegistration"/>s here so each waiter gets its own cancellation token. | ||
| /// </remarks> | ||
| private readonly ConcurrentDictionary<Type, ImmutableHashSet<WaitForActorRegistration>> _actorWaiters = |
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Contemplated just using a simple lock here but it became tricky once we started having the CancellationTokenRegistration delegates also competing to update entries. Opted for the compare-and-swap semantics of the ConcurrentDictionary instead.
Man, this would have been so simple had I just encapsulated all of this inside an actor, but since we're trying to keep this data structure from being dependent on the
ActorSystemitself I went with this.
| return dict => | ||
| { | ||
| // first step during timeout is to remove our registration | ||
| var d = (ConcurrentDictionary<Type, ImmutableHashSet<WaitForActorRegistration>>)dict; |
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We use a blend of closures and passing in state objects via parameters here - I think this is probably fine.
| @@ -53,6 +101,8 @@ public bool TryRegister(Type key, IActorRef actor, bool overwrite = false) | |||
| return _actorRegistrations.TryAdd(key, actor); | |||
| else | |||
| _actorRegistrations[key] = actor; | |||
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| NotifyWaiters(key, _actorRegistrations[key]); | |||
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Notify any waiters each time we push an update.
src/Akka.Hosting/ActorRegistry.cs
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| var registration = ct.Register(CancelWaiter(key, ct, waitingRegistration), _actorWaiters); | ||
| waitingRegistration.CancellationRegistration = registration; | ||
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| _actorWaiters.AddOrUpdate(key, |
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ConcurrentDictionary add semantics make this clean on additions and on removes... I think I'll clean this up for cancellations too.
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Leaving this open for comments in the interim - doubles as a design discussion issue and feature implementation. |
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So I've finally seen a use-case where this feature is necessary out in the wild: user tried to access an actor in the |
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I'll address the merge conflict here |
Enables entries to be added to the `ActorRegistry` later in the future (i.e. actors not started explicitly via Akka.Hosting's delegates - child actors typically) without forcing consumers of the registry to poll for changes.
Aaronontheweb
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Rebased, but I need to add some additional specs for this feature first @Arkatufus |
Somewhat of an experiment - considering adding this to allow non-Akka.NET consumers to
awaitfor anIActorRefto be added to theActorRegistryin the future. I'll be adding tests for theActorRegistryoverall in a separate PR but I have tested this functionality and it does work. However, I don't want to get users into the habit of explicitly awaiting everything from the registry just because we have it - all actors started via aWithActorsdelegate are guaranteed to be created and available in theActorRegistrybefore yourIHost.StartAsyncmethod exits, so you shouldn't need to await theActorRegsitrywhen fetching any top-level actors created by the builder itself.However, if you needed a child actor of some kind - one that is started after the
IHost.StartAsyncmethod completes then this might be useful.Changes
Enables entries to be added to the
ActorRegistrylater in the future (i.e. actors not started explicitly via Akka.Hosting's delegates - child actors typically) without forcing consumers of the registry to poll for changes.Checklist
For significant changes, please ensure that the following have been completed (delete if not relevant):