Akka.TestKit 1.4.47

• .NETStandard 2.0

  • Akka (>= 1.4.47)

Akka.NET v1.4.47 is a maintenance patch for Akka.NET v1.4.46 that includes a variety of bug fixes, performance improvements, and new features.
Actor Telemetry**
Starting in Akka.NET v1.4.47 local and remotely deployed actors will now emit events when being started, stopped, and restarted:
```csharp
public interface IActorTelemetryEvent : INoSerializationVerificationNeeded, INotInfluenceReceiveTimeout
{
/// <summary>
/// The actor who emitted this event.
/// </summary>
IActorRef Subject {get;}
/// <summary>
/// The implementation type for this actor.
/// </summary>
Type ActorType { get; }
}
/// <summary>
/// Event emitted when actor starts.
/// </summary>
public sealed class ActorStarted : IActorTelemetryEvent
{
public IActorRef Subject { get; }
public Type ActorType { get; }
}
/// <summary>
/// Event emitted when actor shuts down.
/// </summary>
public sealed class ActorStopped : IActorTelemetryEvent
{
public IActorRef Subject { get; }
public Type ActorType { get; }
}
/// <summary>
/// Emitted when an actor restarts.
/// </summary>
public sealed class ActorRestarted : IActorTelemetryEvent
{
public IActorRef Subject { get; }
public Type ActorType { get; }
public Exception Reason { get; }
}
```
These events will be consumed from popular Akka.NET observability and management tools such as [Phobos](https://phobos.petabridge.com/) and [Petabridge.Cmd](https://cmd.petabridge.com/) to help provide users with more accurate insights into actor workloads over time, but you can also consume these events yourself by subscribing to them via the `EventStream`:
```csharp
// subscribe to all actor telemetry events
Context.System.EventStream.Subscribe(Self, typeof(IActorTelemetryEvent));
```
By default actor telemetry is disabled** - to enable it you'll need to turn it on via the following HOCON setting:
```hocon
akka.actor.telemetry.enabled = on
```
The performance impact of enabling telemetry is negligible, as you can [see via our benchmarks](https://github.com/akkadotnet/akka.net/pull/6294#issuecomment-1340251897).
Fixes and Updates**
[Akka.Streams: Fixed `System.NotSupportedException` when disposing stage with materialized `IAsyncEnumerable`](https://github.com/akkadotnet/akka.net/issues/6280)
[Akka.Streams: `ReuseLatest` stage to repeatedly emit the most recent value until a newer one is pushed](https://github.com/akkadotnet/akka.net/pull/6262)
[Akka.Remote: eliminate `ActorPath.ToSerializationFormat` UID allocations](https://github.com/akkadotnet/akka.net/pull/6195) - should provide a noticeable Akka.Remote performance improvement.
[Akka.Remote: Remoting and an exception as a payload message ](https://github.com/akkadotnet/akka.net/issues/3903) - `Exception` types are now serialized properly inside `Status.Failure` messages over the wire. `Status.Failure` and `Status.Success` messages are now managed by Protobuf - so you might see some deserialization errors while upgrading if those types are being exchanged over the wire.
[Akka.TestKit: `TestActorRef` can not catch exceptions on asynchronous methods](https://github.com/akkadotnet/akka.net/issues/6265)
You can see the [full set of tracked issues for Akka.NET v1.4.47 here](https://github.com/akkadotnet/akka.net/issues?q=is:closed+milestone:1.4.47).
| COMMITS | LOC+ | LOC- | AUTHOR |
| --- | --- | --- | --- |
| 10 | 2027 | 188 | Aaron Stannard |
| 1 | 157 | 10 | Gregorius Soedharmo |