Extensions and Context Decorators

Proto.Actor can be extended at both the actor and actor system level.

Context Decorators

Context decorators allow developers to surround actors with custom functionality, from custom message receive logic to intercepting outgoing calls.

To apply context decorators to an actor, use the Props.WithContextDecorator method.

graph LR
    Sender --> Decorator --> Actor

.NET

public class MyDecorator : IContextDecorator
{
    public IContext Decorate(IContext context) => new MyContext(context);
}

var props = Props.FromProducer(() => new MyActor())
    .WithContextDecorator(new MyDecorator());

Go

func myDecorator(next actor.ContextDecoratorFunc) actor.ContextDecoratorFunc {
    return func(ctx actor.Context) actor.Context {
        return &myContext{Context: next(ctx)}
    }
}

props := actor.PropsFromProducer(func() actor.Actor { return &myActor{} },
    actor.WithContextDecorator(myDecorator))

Actor Extensions

Actor extensions allow adding cross-cutting functionality to individual actors by decorating their IContext. They are ideal for concerns such as logging or metrics and build upon the context decorator mechanism shown above.

Actor System Extensions

Actor system extensions provide hooks into the lifecycle of the entire ActorSystem.

graph TD
    System[ActorSystem] --> Ext[Extension]

.NET

public class MyExtension : IActorSystemExtension { }

var system = new ActorSystem();
system.Extensions.Register(new MyExtension());

Go

import "github.com/asynkron/protoactor-go/extensions"

var extID = extensions.NextExtensionID()

type myExtension struct{}

func (*myExtension) ExtensionID() extensions.ExtensionID {
    return extID
}

system := actor.NewActorSystem()
system.Extensions.Register(&myExtension{})

Conceptual overview

This overview aims to show how the different extension points of Proto.Actor interact together.