3.4.1 RuntimeError

[belongwqz]

1.pip install django
Successfully installed asgiref-3.4.1 django-3.2.6 pytz-2021.1 sqlparse-0.4.1
2.django-admin startproject Sample

Traceback (most recent call last):
  File "/django_venv/bin/django-admin", line 6, in <module>
    from django.core.management import execute_from_command_line
  File "/django_venv/lib/python3.8/site-packages/django/core/management/__init__.py", line 13, in <module>
    from django.apps import apps
  File "/django_venv/lib/python3.8/site-packages/django/apps/__init__.py", line 1, in <module>
    from .config import AppConfig
  File "/django_venv/lib/python3.8/site-packages/django/apps/config.py", line 7, in <module>
    from django.utils.deprecation import RemovedInDjango41Warning
 File "/django_venv/lib/python3.8/site-packages/django/utils/deprecation.py", line 5, in <module>
    from asgiref.sync import sync_to_async
  File "/django_venv/lib/python3.8/site-packages/asgiref/sync.py", line 304, in <module>
    class SyncToAsync:
  File "/django_venv/lib/python3.8/site-packages/asgiref/sync.py", line 328, in SyncToAsync
    loop = get_running_loop()
RuntimeError: no running event loop

But use version 3.3.4 will be OK.

[andrewgodwin]

I cannot replicate this on my side - it works exactly as expected. Can you provide a full pip freeze of your package list, tell us your OS and architecture, and show us what command you are running?

[belongwqz]

I cannot replicate this on my side - it works exactly as expected. Can you provide a full pip freeze of your package list, tell us your OS and architecture, and show us what command you are running?

env info as follow:

python version:3.8.2

OS:Red Hat Enterprise Linux Server 2.6.32-431.el6.x86_64

pip freeze:
asgiref==3.4.1
Django==3.2.6
pytz==2021.1
sqlparse==0.4.1

I just create a venv use command python -m venv django_venv, then activate itcd django_venv;. bin/activate.
After that, I install django use command pip install django, at last execute django-admin startproject Sample.
If I downgrade to version 3.3.4pip install asgiref==3.3.4, then the startproject commond success.

What's more, I try version 3.4.1 on windows and it works. Looks only linux has this problem.

[carltongibson]

I can reproduce this. It's because you have the ASGI_THREADS environment variable set, and the offending get_running_loop() is called at class definition in that case:

~ $ python --version
Python 3.9.6
~ $ mktmpenv
...
This is a temporary environment. It will be deleted when you run 'deactivate'.
(tmp-98dde6625b183cc) ~/ve/tmp-98dde6625b183cc $ pip install Django
Collecting Django
  Using cached Django-3.2.6-py3-none-any.whl (7.9 MB)
Collecting sqlparse>=0.2.2
  Using cached sqlparse-0.4.1-py3-none-any.whl (42 kB)
Collecting asgiref<4,>=3.3.2
  Using cached asgiref-3.4.1-py3-none-any.whl (25 kB)
Collecting pytz
  Using cached pytz-2021.1-py2.py3-none-any.whl (510 kB)
Installing collected packages: sqlparse, pytz, asgiref, Django
Successfully installed Django-3.2.6 asgiref-3.4.1 pytz-2021.1 sqlparse-0.4.1
WARNING: You are using pip version 21.1.3; however, version 21.2.4 is available.
You should consider upgrading via the '/Users/carlton/ve/tmp-98dde6625b183cc/bin/python -m pip install --upgrade pip' command.
(tmp-98dde6625b183cc) ~/ve/tmp-98dde6625b183cc $ django-admin startproject Sample
(tmp-98dde6625b183cc) ~/ve/tmp-98dde6625b183cc $ ls
README.tmpenv Sample        bin           lib           pyvenv.cfg
(tmp-98dde6625b183cc) ~/ve/tmp-98dde6625b183cc $ rm -rf Sample
(tmp-98dde6625b183cc) ~/ve/tmp-98dde6625b183cc $ tail -n +326 ~/Documents/Django-Stack/asgiref/asgiref/sync.py | head -n 7
    # If they've set ASGI_THREADS, update the default asyncio executor for now
    if "ASGI_THREADS" in os.environ:
        loop = get_running_loop()
        loop.set_default_executor(
            ThreadPoolExecutor(max_workers=int(os.environ["ASGI_THREADS"]))
        )

(tmp-98dde6625b183cc) ~/ve/tmp-98dde6625b183cc $ ASGI_THREADS=4 django-admin startproject Sample
Traceback (most recent call last):
    ...FRAMES OMITTED... 
  File "/Users/carlton/ve/tmp-98dde6625b183cc/lib/python3.9/site-packages/django/utils/deprecation.py", line 5, in <module>
    from asgiref.sync import sync_to_async
  File "/Users/carlton/ve/tmp-98dde6625b183cc/lib/python3.9/site-packages/asgiref/sync.py", line 304, in <module>
    class SyncToAsync:
  File "/Users/carlton/ve/tmp-98dde6625b183cc/lib/python3.9/site-packages/asgiref/sync.py", line 328, in SyncToAsync
    loop = get_running_loop()
RuntimeError: no running event loop

asgiref/asgiref/sync.py

Lines 329 to 334 in f53fbef

	# If they've set ASGI_THREADS, update the default asyncio executor for now
	if "ASGI_THREADS" in os.environ:
	loop = get_running_loop()
	loop.set_default_executor(
	ThreadPoolExecutor(max_workers=int(os.environ["ASGI_THREADS"]))
	)

[belongwqz]

I can reproduce this. It's because you have the ASGI_THREADS environment variable set, and the offending get_running_loop() is called at class definition in that case:

~ $ python --version
Python 3.9.6
~ $ mktmpenv
...
This is a temporary environment. It will be deleted when you run 'deactivate'.
(tmp-98dde6625b183cc) ~/ve/tmp-98dde6625b183cc $ pip install Django
Collecting Django
  Using cached Django-3.2.6-py3-none-any.whl (7.9 MB)
Collecting sqlparse>=0.2.2
  Using cached sqlparse-0.4.1-py3-none-any.whl (42 kB)
Collecting asgiref<4,>=3.3.2
  Using cached asgiref-3.4.1-py3-none-any.whl (25 kB)
Collecting pytz
  Using cached pytz-2021.1-py2.py3-none-any.whl (510 kB)
Installing collected packages: sqlparse, pytz, asgiref, Django
Successfully installed Django-3.2.6 asgiref-3.4.1 pytz-2021.1 sqlparse-0.4.1
WARNING: You are using pip version 21.1.3; however, version 21.2.4 is available.
You should consider upgrading via the '/Users/carlton/ve/tmp-98dde6625b183cc/bin/python -m pip install --upgrade pip' command.
(tmp-98dde6625b183cc) ~/ve/tmp-98dde6625b183cc $ django-admin startproject Sample
(tmp-98dde6625b183cc) ~/ve/tmp-98dde6625b183cc $ ls
README.tmpenv Sample        bin           lib           pyvenv.cfg
(tmp-98dde6625b183cc) ~/ve/tmp-98dde6625b183cc $ rm -rf Sample
(tmp-98dde6625b183cc) ~/ve/tmp-98dde6625b183cc $ tail -n +326 ~/Documents/Django-Stack/asgiref/asgiref/sync.py | head -n 7
    # If they've set ASGI_THREADS, update the default asyncio executor for now
    if "ASGI_THREADS" in os.environ:
        loop = get_running_loop()
        loop.set_default_executor(
            ThreadPoolExecutor(max_workers=int(os.environ["ASGI_THREADS"]))
        )

(tmp-98dde6625b183cc) ~/ve/tmp-98dde6625b183cc $ ASGI_THREADS=4 django-admin startproject Sample
Traceback (most recent call last):
    ...FRAMES OMITTED... 
  File "/Users/carlton/ve/tmp-98dde6625b183cc/lib/python3.9/site-packages/django/utils/deprecation.py", line 5, in <module>
    from asgiref.sync import sync_to_async
  File "/Users/carlton/ve/tmp-98dde6625b183cc/lib/python3.9/site-packages/asgiref/sync.py", line 304, in <module>
    class SyncToAsync:
  File "/Users/carlton/ve/tmp-98dde6625b183cc/lib/python3.9/site-packages/asgiref/sync.py", line 328, in SyncToAsync
    loop = get_running_loop()
RuntimeError: no running event loop

asgiref/asgiref/sync.py

Lines 329 to 334 in f53fbef

	# If they've set ASGI_THREADS, update the default asyncio executor for now
	if "ASGI_THREADS" in os.environ:
	loop = get_running_loop()
	loop.set_default_executor(
	ThreadPoolExecutor(max_workers=int(os.environ["ASGI_THREADS"]))
	)

Yes, it is, thanks!

[carltongibson]

Hey @belongwqz — Glad that's got you moving!

I'm going to reopen to let @andrewgodwin decide whether an adjustment is needed here. Presumably setting ASGI_THREADS is valid, and this class module can get imported before the event loop starts.

[andrewgodwin]

Thanks Carlton - that was indeed the problem. I've just pushed up a fix, will try and get it into a release soon.

[carltongibson]

Thanks @andrewgodwin 🥇

[variable]

@carltongibson

I am not sure if this is solely because of the ASGI_THREADS environment settings, cos it also gives the same error on when running manage.py runworker <channel> and there is no ASGI_THREADS defined.

Running worker for channels ['multiplex']
INFO  2021-09-01 12:08:59,526  runworker 17875  140146458650432  Running worker for channels ['multiplex']
Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/srv/www/portal/lib/python3.8/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/srv/www/portal/lib/python3.8/site-packages/django/core/management/__init__.py", line 375, in execute 
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/srv/www/portal/lib/python3.8/site-packages/django/core/management/base.py", line 323, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/srv/www/portal/lib/python3.8/site-packages/django/core/management/base.py", line 364, in execute 
    output = self.handle(*args, **options)
  File "/srv/www/portal/lib/python3.8/site-packages/channels/management/commands/runworker.py", line 46, in handle
    worker.run()
  File "/srv/www/portal/lib/python3.8/site-packages/asgiref/server.py", line 61, in run
    event_loop = get_running_loop()
RuntimeError: no running event loop

[variable]

ahh nevermind, seems this is duplicate of #278

[aaronmader]

Any idea when this fix will be released?

[andrewgodwin]

I just have to get around to it - not sure when. Pandemic has put everything out of kilter.