How to pass asyncio.get_event_loop() to quart in command line?

Question

In a doc they passed event loop to quart. Need to call async method in route handler.

How to change this to command line for heroku?

if __name__ == '__main__':
    loop=asyncio.get_event_loop()
    app.run(loop=loop)

I tried

web: hypercorn  -b 0.0.0.0:${PORT} --workers=1 telegram:app -k asyncio

But still got

2019-06-22 10:00:45.047703 app[web.1]:  Task <Task pending coro=<ASGIWebsocketConnection.handle_websocket() running at /app/.heroku/python/lib/python3.7/site-packages/quart/asgi.py:135> cb=[_wait.<locals>._on_completion() at /app/.heroku/python/lib/python3.7/asyncio/tasks.py:440]> got Future <Future pending> attached to a different loop
2019-06-22 10:00:45.048350 app[web.1]:  Traceback (most recent call last):
2019-06-22 10:00:45.048395 app[web.1]:  File "/app/tele.py", line 34, in create_contact
2019-06-22 10:00:45.048399 app[web.1]:  contacts =await client2(functions.contacts.ImportContactsRequest([contact]))
2019-06-22 10:00:45.048410 app[web.1]:  File "/app/.heroku/python/lib/python3.7/site-packages/telethon/client/users.py", line 60, in __call__
2019-06-22 10:00:45.048414 app[web.1]:  result = await future
2019-06-22 10:00:45.048458 app[web.1]:  RuntimeError: Task <Task pending coro=<ASGIWebsocketConnection.handle_websocket() running at /app/.heroku/python/lib/python3.7/site-packages/quart/asgi.py:135> cb=[_wait.<locals>._on_completion() at /app/.heroku/python/lib/python3.7/asyncio/tasks.py:440]> got Future <Future pending> attached to a different loop

Follow up question for this

How to obtain an event loop from Quart here says quart's app.run() uses the default event loop created by asyncio for the main thread Then why they pass the loop?

https://github.com/LonamiWebs/Telethon/pull/1207 with heroku — Smart Manoj, Jun 24 '19 at 17:32
Shouldn't the last two lines be inside a `if __name__ == '__main__':`? — Tarun Lalwani, Jun 25 '19 at 12:53

score 3 · Answer 1 · answered Jun 27 '19 at 12:53

3

Because hypercorn will not go inside if __main__, you need to create loop beforehand and set it as default:

loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)
# do whatever you want, e.g.: 
# loop.create_task(background())

if __name__ == '__main__':
    loop = asyncio.get_event_loop()  # now unnecessary
    app.run(loop=loop)

# should be just
if __name__ == '__main__':
    app.run()

answered Jun 27 '19 at 12:53

aiven

3,775
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Will hypercorn use the loop we created? – Smart Manoj Jul 01 '19 at 04:13
Need to call async method in route handler. – Smart Manoj Jul 01 '19 at 04:39

score 1 · Answer 2 · answered Jul 12 '19 at 13:11

1

Opening client inside before_serving solved this.

answered Jul 12 '19 at 13:11

Smart Manoj

5,230
4
34
59

How to pass asyncio.get_event_loop() to quart in command line?

2 Answers2