Killing greenlet returned from future_to_greenlet throws AttributeError: 'coroutine' object has no attribute 'cancel'

[OpaqueOrangutan]

I'm chasing down a 100% CPU consumption problem that is somewhere in gevent's hub run while running greenlets from future_to_greenlet.

While investigating, I wanted to make sure that greenlets were killed after being joined. (For context, I'm creating and running these futures in parallel using locust so it's a bit tricky to make sure everything is getting cleaned up.)

My code looked something like this:

future = my_async_function()
greenlet = asyncio_gevent.future_to_greenlet(future)
greenlet.start()
greenlet.join(timeout=timeout_seconds)
greenlet.kill()

But I was receiving an AttributeError: 'coroutine' object has no attribute 'cancel' during greenlet.kill(), thrown from https://github.com/gfmio/asyncio-gevent/blob/main/asyncio_gevent/future_to_greenlet.py#L61

Should this instead be future.close()? Coroutine documentation is here. This seems to work for me. My example now looks like:

future = my_async_function()
greenlet = asyncio_gevent.future_to_greenlet(future, autocancel_future=False)
greenlet.start()
greenlet.join(timeout=timeout_seconds)
greenlet.kill()
future.close()

[gfmio]

Thanks for raising this issue. I think the problem is that I expected the object in the file you link ed to be a future, not a coroutine object. asyncio.Future objects have a cancel() method.

To fix your code right now, I would suggest using asyncio.wrap_future to wrap your coroutine object inside a future.

And separately, I'll update the library to also support coroutine objects, because I can see why this would be unexpected/confusing.