[issue39232] asyncio crashes when tearing down the proactor event loop
Shane Mai
report at bugs.python.org
Mon Aug 23 08:27:41 EDT 2021
Shane Mai <machine.gw at gmail.com> added the comment:
I added some code to wait for all tasks completion before exit:
currentTask = asyncio.current_task()
for t in asyncio.all_tasks():
if currentTask != t:
await t
and still got the exception
Then I think it created additional thread somewhere and created an event_loop inside it. To dig it out I sub-classed threading.Thread. I also wait for all tasks in all threads before exiting:
loops: list[asyncio.AbstractEventLoop] = []
class MyThread(threading.Thread):
def start(self):
global loops
loops.append(asyncio.get_event_loop())
super().start()
async def func1():
async with aiohttp.ClientSession() as session:
async with session.get('https://www.okex.com/api/v5/public/time') as resp:
print(resp.status)
print(await resp.json())
threading.Thread = MyThread
import aiohttp
async def main():
global loops
loops.append(asyncio.get_running_loop())
print(sys.argv)
task = asyncio.create_task(func1())
await task
print('done.')
currentTask = asyncio.current_task()
for loop in loops:
for t in asyncio.all_tasks(loop):
if currentTask != t:
await t
print('done2.')
#await asyncio.sleep(1)
#if __file__ == '__main__':
asyncio.run(main())
Then I found out the thread is created inside _loop.getaddrinfo: (files are from python 3.9.6)
File aiohttp\resolver.py, line 31, in ThreadedResolver.resolve
FILE asyncio\base_events.py, line 856, in BaseEventLoop(ProactorEventLoop).getaddrinfo
And it is strange that another thread is created when program exit:
FILE asyncio\base_events.py, line 563, in BaseEventLoop(ProactorEventLoop).shutdown_default_executor
But sad it seems vscode cannot break a __del__ call. If I break somewhere else first then it would not crash:(
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nosy: +machine.gw
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<https://bugs.python.org/issue39232>
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