[Core] ray.actor.exit_actor() does not seem to work from within an async background thread

[shomilj]

What happened + What you expected to happen

In actor initialization, I want to spawn an async background routine that has the ability to call ray.actor.exit_actor(); however, that API doesn't seem to actually work -

>>> AsyncActor.remote()
2024-12-26 14:20:31,392 INFO worker.py:1743 -- Started a local Ray instance. View the dashboard at 127.0.0.1:8265 
Actor(AsyncActor, e6db65d56c5f1e1f1122d91301000000)
>>> (AsyncActor pid=2151093) Exiting actor

The actor stays alive (according to Ray dashboard) instead of exiting as I would expect.

Versions / Dependencies

Ray 2.40.0

Reproduction script

import ray
import asyncio

@ray.remote
class AsyncActor:
    def __init__(self) -> None:
        self.task = asyncio.get_running_loop().create_task(
            self.start()
        )

    async def start(self):
        print("Exiting actor")
        ray.actor.exit_actor()
        print("Exited actor")

Issue Severity

Medium: It is a significant difficulty but I can work around it.

[MortalHappiness]

@shomilj Is this bug only occurring occasionally, or can it always be reproduced using your reproduction script? I tried your script but couldn't reproduce it.

Update: I can reproduce it now.

[edoakes]

@MortalHappiness I think we can fix this by unifying the asyncio exit path with the check_signals codepath:

ray/src/ray/core_worker/core_worker.cc

Line 3165 in fef9596

if (options_.check_signals) {

Basically, when exit_actor is called, it can set a threading.Event that is checked during check_signals (which is already called periodically by the core worker).

[MortalHappiness]

@edoakes Thanks for your information!