How correct find actor or spawn in on place

Question

I'm try use akka-typed in homepet project, but don't know how correct find actor or spawn and send message. My first try: wrapped "listing" from receptionist and send over adapter - very wordy and need always wear command for actor Second try: create function "tellToXXX"

private Behavior<Command> tellToWorker(ServiceKey<Worker.Command> serviceKey, Worker.Command command) {
    record WrappedFindResult(Receptionist.Listing listing, Throwable failure) implements Command {
    }

    var system = getContext().getSystem();
    getContext().pipeToSelf(
            AskPattern.ask(
                    system.receptionist(),
                    replyTo -> Receptionist.find(serviceKey, replyTo),
                    Duration.ofSeconds(1),
                    system.scheduler()),
            WrappedFindResult::new);

    return Behaviors.receive(Command.class)
            .onMessage(WrappedFindResult.class, result -> {
                result.listing().getServiceInstances(serviceKey).stream().findFirst()
                        .orElseGet(() -> getContext().spawnAnonymous(Worker.create()))
                        .tell(command);

                return this;
            }).build();
}

how correct this? thx

Answer 1

Assuming that your actor is the only one that will spawn the worker actors (by implication: the workers are local), you don't need to bother with registering with the receptionist: building a Map<ServiceKey<Worker.Command>, ActorRef<Worker.Command>> and saving that in the actor is sufficient. Then when you need a worker, look up the ServiceKey in the Map: if there isn't one, then spawn and save in the actor. If there's only one ServiceKey, then an Optional<ActorRef<Worker.Command>> works.

Additionally, if there are multiple workers all doing the same job, routers may be worth considering: you spawn an actor and send it messages; the actor forwards them to a pool of workers (the behaviors of which are provided by you) which it manages.