set_wakeup_fd() only works in main thread

[MeneMeneTekel]

BPO	43007
Nosy	@gvanrossum, @asvetlov, @1st1

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2021-11-20.18:01:02.250>
created_at = <Date 2021-01-23.10:40:30.388>
labels = ['3.9', 'type-crash', 'expert-asyncio']
title = 'set_wakeup_fd() only works in main thread'
updated_at = <Date 2021-11-20.18:01:02.249>
user = 'https://bugs.python.org/MeneMeneTekel'

bugs.python.org fields:

activity = <Date 2021-11-20.18:01:02.249>
actor = 'MeneMeneTekel'
assignee = 'none'
closed = True
closed_date = <Date 2021-11-20.18:01:02.250>
closer = 'MeneMeneTekel'
components = ['asyncio']
creation = <Date 2021-01-23.10:40:30.388>
creator = 'MeneMeneTekel'
dependencies = []
files = []
hgrepos = []
issue_num = 43007
keywords = []
message_count = 3.0
messages = ['385528', '395084', '406679']
nosy_count = 4.0
nosy_names = ['gvanrossum', 'asvetlov', 'yselivanov', 'MeneMeneTekel']
pr_nums = []
priority = 'normal'
resolution = 'works for me'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue43007'
versions = ['Python 3.9']

[MeneMeneTekel]

This problem is marked as solved in bpo-38563, BUT the solution refers to some signal issues being solved - I'm using Python 3.8.7 on windows 10, where a signal solution may not work. I.e. my django (vers. 3.1.5) website crashes every second call with the message:

File "C:\Winpython\WPy64-3870\python-3.8.7.amd64\lib\asyncio\proactor_events.py", line 632, in __init__
signal.set_wakeup_fd(self._csock.fileno())
ValueError: set_wakeup_fd only works in main thread

[MeneMeneTekel]

Update: I just tried it again with

• Windows 10 Pro, 21H1
• WinPython 3.9.4
• Apache24
• Django 3.2.4
• mod_wsgi-4.8.0-cp39-cp39-win_amd64

Actually, there is no change, it got even worse. i.e. this wake up situation occurs more often.

Remember: Changing WinPython 3.9.4 to WinPython 3.7.7 with mod_wsgi-4.7.1-cp37-cp37m-win_amd64 and all works fine!

Perhaps it's useful to have a stack trace? Here we are:

******
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819] mod_wsgi (pid=6556): Failed to exec Python script file 'C:/.../.../.../wsgi.py'.
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819] mod_wsgi (pid=6556): Exception occurred processing WSGI script 'C:/.../.../.../wsgi.py'.
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819] Traceback (most recent call last):\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]   File "C:/.../.../.../wsgi.py", line 19, in <module>\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]     application = get_wsgi_application()\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]   File "C:\\Winpython\\WPy64-3940\\python-3.9.4.amd64\\lib\\site-packages\\django\\core\\wsgi.py", line 13, in get_wsgi_application\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]     return WSGIHandler()\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]   File "C:\\Winpython\\WPy64-3940\\python-3.9.4.amd64\\lib\\site-packages\\django\\core\\handlers\\wsgi.py", line 127, in __init__\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]     self.load_middleware()\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]   File "C:\\Winpython\\WPy64-3940\\python-3.9.4.amd64\\lib\\site-packages\\django\\core\\handlers\\base.py", line 58, in load_middleware\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]     mw_instance = middleware(adapted_handler)\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]   File "C:\\Users\\mail\\OneDrive\\Dokumente\\Privat\\Python\\Django\\Applications\\groupregister\\middleware\\sessions.py", line 54, in __init__\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]     self.user_reg = get_user_model().objects \\\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]   File "C:\\Winpython\\WPy64-3940\\python-3.9.4.amd64\\lib\\site-packages\\django\\db\\models\\query.py", line 399, in aggregate\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]     return query.get_aggregation(self.db, kwargs)\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]   File "C:\\Winpython\\WPy64-3940\\python-3.9.4.amd64\\lib\\site-packages\\django\\db\\models\\sql\\query.py", line 502, in get_aggregation\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]     result = compiler.execute_sql(SINGLE)\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]   File "C:\\Winpython\\WPy64-3940\\python-3.9.4.amd64\\lib\\site-packages\\django\\db\\models\\sql\\compiler.py", line 1173, in execute_sql\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]     cursor = self.connection.cursor()\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]   File "C:\\Winpython\\WPy64-3940\\python-3.9.4.amd64\\lib\\site-packages\\django\\utils\\asyncio.py", line 19, in inner\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]     event_loop = asyncio.get_event_loop()\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]   File "C:\\Winpython\\WPy64-3940\\python-3.9.4.amd64\\lib\\asyncio\\events.py", line 639, in get_event_loop\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]     self.set_event_loop(self.new_event_loop())\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]   File "C:\\Winpython\\WPy64-3940\\python-3.9.4.amd64\\lib\\asyncio\\events.py", line 659, in new_event_loop\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]     return self._loop_factory()\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]   File "C:\\Winpython\\WPy64-3940\\python-3.9.4.amd64\\lib\\asyncio\\windows_events.py", line 310, in __init__\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]     super().__init__(proactor)\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]   File "C:\\Winpython\\WPy64-3940\\python-3.9.4.amd64\\lib\\asyncio\\proactor_events.py", line 632, in __init__\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819]     signal.set_wakeup_fd(self._csock.fileno())\r
[Fri Jun 04 15:31:37.428939 2021] [wsgi:error] [pid 6556:tid 1140] [client 111.222.333.444:50819] ValueError: set_wakeup_fd only works in main thread of the main interpreter\r
******

Would be nice to be able to switch zu Python 3.9.4 ff. soon...

Many thanks,
MeneMeneTekel

[MeneMeneTekel]

Finally... it works for me - I migrated to

• Windows Server 2019 Datacenter
• WinPython 3.9.5
• Apache24 AH
• Django 3.2.9
• mod_wsgi-4.9.0-cp39-cp39-win_amd64

Whoever made that it works again.... thanks a lot ;-)

MeneMeneTekel