Is there a better way to store/pass a reference to "self" within a service?

[Asderex]

Hi, Is there any way a service can obtain a reference to itself from inside the service? I was going to pass it in as an event and store it on the context after the service was started but was wondering if there was a more elegant solution. I'm sure there are anti-pattern alarms ringing loudly but this solution would be ideal for my particular problem and passing the reference in as an event after the service has started feels unnecesarily janky... ideally i would like to be able to do something like....

actions: (context, event) => event.someOtherMachineReference.send( { type: 'REGISTER_FOR_UPDATES', returnAddress: context.self } )

where context.self is a reference to the service running the action and someOtherMachineReference will use the passed in reference (self.send) to send future updates. (note: for the avoidance of doubt I'm aware of onTransition)

"No" is both a complete sentence and welcome reponse if correct.

[Andarist]

"No" is both a complete sentence and welcome reponse if correct.

😅

No.

[Andarist]

But to be more serious - there probably should be a better way to do this. Could u file an issue asking about this so we can discuss more details there? This probably would not be available as part of the context as that is fully under the control of the user and a self/sessionId is a system-controlled "variable" and as such we probably should provide it as part of the 3rd argument (so-called meta). This ain't super trivial to add right now because of the Machine/interpreter APIs split and how they interact with each other - but we should brainstorm how to make this happen in the least disruptive manner.

[Asderex]

Thanks for the confirmation @Andarist - looks like this is something David has been thinking about too so will file that issue if he wants to track it expliciltly.

[davidkpiano]

In version 5, there will be. Being able to reference self is important in an actor-model framework (Akka provides the "self" value in the "actor context") and there's even a way to do this for assign calls in the v5 branch:

actions: assign((ctx, e, { spawn, self }) => {
  // `self` refers to the ActorRef instance of this machine
})

We just need to make that self reference generally available to all "meta data".

[Asderex]

Thanks David - It sounds like this is well in hand but did you want me to file an issue as suggested by @Andarist for tracking purposes or is this not required?

[davidkpiano]

It's not required.