Skip to content

Instantly share code, notes, and snippets.

@ultrafunkamsterdam

ultrafunkamsterdam/Python 3.6 Asyncio multiple async event loops in multiple threads. Running and shutting down gracefully.py

Last active December 16, 2023 01:33
Show Gist options
  • Save ultrafunkamsterdam/8be3d55ac45759aa1bd843ab64ce876d to your computer and use it in GitHub Desktop.
Save ultrafunkamsterdam/8be3d55ac45759aa1bd843ab64ce876d to your computer and use it in GitHub Desktop.
Download ZIP
Python 3.6 Asyncio multiple async event loops in multiple threads. Running and shutting down gracefully
Raw
Python 3.6 Asyncio multiple async event loops in multiple threads. Running and shutting down gracefully.py
import asyncio
import threading
import random
import time
async def coro(n, name):
for i in range(n):
sleep_time = random.uniform(.3, .7)
print('coro({0}) [{1}/{2}] -> sleep_time {3:.2f}'.format(name, i, n, sleep_time), flush=True)
await asyncio.sleep(sleep_time)
return 'coro {} is finished!'.format(name)
def create_bg_loop():
def to_bg(loop):
asyncio.set_event_loop(loop)
try:
loop.run_forever()
except asyncio.CancelledError as e:
print('CANCELLEDERROR {}'.format(e))
finally:
for task in asyncio.Task.all_tasks():
task.cancel()
loop.run_until_complete(loop.shutdown_asyncgens())
loop.stop()
loop.close()
new_loop = asyncio.new_event_loop()
t = threading.Thread(target=to_bg, args=(new_loop,))
t.start()
return new_loop
# create and run a background loop
bg_loop = create_bg_loop()
task = asyncio.run_coroutine_threadsafe(coro(10, 'bg_loop'), bg_loop)
# create and run a background loop
bg_loop1 = create_bg_loop()
task1 = asyncio.run_coroutine_threadsafe(coro(10, 'bg_loop1'), bg_loop)
# create and run a background loop
bg_loop2 = create_bg_loop()
task2 = asyncio.run_coroutine_threadsafe(coro(10, 'bg_loop2'), bg_loop)
# create and run a background loop
bg_loop3 = create_bg_loop()
task3 = asyncio.run_coroutine_threadsafe(coro(10, 'bg_loop3'), bg_loop)
# get main loop and run until complete
main_loop = asyncio.get_event_loop()
main_task = main_loop.run_until_complete(coro(10,'main_loop'))
print('\n\n[ background task return values ]\n\n')
print(task.result())
print(task1.result())
print(task2.result())
print(task3.result())
print(main_task)
print('\n\n[ starting extra jobs to show them being cancelled gracefully ]\n\n')
task_ext = asyncio.run_coroutine_threadsafe(coro(10, 'extended job bg_loop'), bg_loop)
task_ext1 = asyncio.run_coroutine_threadsafe(coro(10, 'extended job bg_loop1'), bg_loop1)
task_ext2 = asyncio.run_coroutine_threadsafe(coro(10, 'extended job bg_loop2'), bg_loop2)
task_ext3 = asyncio.run_coroutine_threadsafe(coro(10, 'extended job bg_loop3'), bg_loop3)
# simulate some time
time.sleep(2)
print('\n\n[ closing main loop ]\n\n')
main_loop.close()
print('\n\n[ stopping all background loops using threadsafe calls ]\n\n')
bg_loop.call_soon_threadsafe(bg_loop.stop)
bg_loop1.call_soon_threadsafe(bg_loop1.stop)
bg_loop2.call_soon_threadsafe(bg_loop2.stop)
bg_loop3.call_soon_threadsafe(bg_loop3.stop)
print('[ finished all! bye! ]')
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment