Opened 2 years ago
Last modified 2 years ago
#34747 closed Bug
Django hangs on async views with asycio.gather and an async ORM call — at Initial Version
| Reported by: | rasca | Owned by: | nobody |
|---|---|---|---|
| Component: | Database layer (models, ORM) | Version: | 4.2 |
| Severity: | Normal | Keywords: | async asyncio.gather |
| Cc: | Triage Stage: | Unreviewed | |
| Has patch: | no | Needs documentation: | no |
| Needs tests: | no | Patch needs improvement: | no |
| Easy pickings: | no | UI/UX: | no |
Description
This simple view:
import asyncio
from django.http import HttpResponse
from myapp.models import MyModel
async def test_hang(request):
await asyncio.gather(MyModel.objects.acreate())
return HttpResponse('OK')
Hangs when called from daphne or uvicorn. When called from the django shell (with ipdb) like await test_hang(None) it works with no problem.
I created this minimal view to reproduce the issue, but in my project I'm creating a lot of tasks that have long external API requests saving the results to the db. Notice that with only one task it already hangs.
I haven't found anything in the async documentation / channels / daphne stating that I cannot do something like this.
When setting a trace with ipdb I found that the line that gets stuck is:
> /usr/local/Cellar/python@3.11/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/selectors.py:561 kev_list = self._selector.control(None, max_ev, timeout)
And when running with python -m ipdb and then ctrl c it gets stuck in this line:
File "/usr/local/Cellar/python@3.11/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/threading.py", line 1132, in _wait_for_tstate_lock
if lock.acquire(block, timeout):
Shouldn't this simple view be working? If not, we should document it somehow. Any pointers much appreciated!