compatibility issue when asyncio loop policy is not the default one

[nlgranger]

get_session blocks when the loop policy is not the default one, for instance when using asyncio-glib:

import asyncio_glib
import asyncio

asyncio.set_event_loop_policy(asyncio_glib.GLibEventLoopPolicy())
from arsenic import services, browsers, get_session

async def loop():
    while True:
        await asyncio.sleep(0.5)
        print('.', end='', flush=True)

async def main():
    service = services.Geckodriver()
    browser = browsers.Firefox()
    print('ready?')
    async with get_session(service, browser) as d:
        await d.get('https://www.google.fr')
        print("done")

asyncio.run(asyncio.wait([main(), loop()]))

[dimaqq]

Interesting... any idea what's actually blocking? Is it trying to spawn geckodriver? Or trying to connect to its port? Or is it the .get(...) operation, which, in essence is aiohttp request?

[nlgranger]

I do not see any geckodriver process and I just noticed the python process uses 100% of a CPU while blocking on get_session.

[nlgranger]

It block when checking the version of geckodriver, here is the call stack:

run_process (.../venv/lib/python3.9/site-packages/arsenic/subprocess.py:46)
_check_version (.../venv/lib/python3.9/site-packages/arsenic/services.py:73)
start (.../venv/lib/python3.9/site-packages/arsenic/services.py:92)
start_session (.../venv/lib/python3.9/site-packages/arsenic/__init__.py:28)
__aenter__ (.../venv/lib/python3.9/site-packages/arsenic/__init__.py:16)
main (.../test.py:18)
_run (/usr/lib/python3.9/asyncio/events.py:80)
_run_once (/usr/lib/python3.9/asyncio/base_events.py:1882)
run_forever (/usr/lib/python3.9/asyncio/base_events.py:596)
run_until_complete (/usr/lib/python3.9/asyncio/base_events.py:629)
run (/usr/lib/python3.9/asyncio/runners.py:44)
<module> (.../test.py:24)

[dimaqq]

https://github.com/HDE/arsenic/blob/7323c550a46b94aa0dcda6659b9c3eff11bec3f0/src/arsenic/subprocess.py#L46 code in question...

I wonder if asyncio.create_subprocess_exec and process.communicate are supported in this custom event loop 🤔

[dimaqq]

It could be smth like https://github.com/jhenstridge/asyncio-glib/issues/5 🤔

[dimaqq]

Given that the last update to asyncio_glib was almost 2 years ago, I'm tempted to point my finger there.

[nlgranger]

Indeed, I will try something else for glib event loop interaction. Thanks for looking into this.