[SOLVED] Django Webfaction 'Timeout when reading response headers from daemon process'

Django Webfaction 'Timeout when reading response headers from daemon process'

My Django app on my production server hosted on Webfaction was working fine until I just tried to restart it after pushing a change to the settings.py file. I ran

apache2/bin/restart

as usual. Then I tried to access my app on my browser, and I got a 504 Gateway timeout. I looked into the mod_wsgi logs and saw this:

[Thu Nov 03 23:46:53.605625 2016] [wsgi:error] [pid 8027:tid 139641332168448]
[client 127.0.0.1:34570] Timeout when reading response headers from daemon 
process 'myapp' : /home/<me>/webapps/<myapp>/<ProjectName>/<myapp>/wsgi.py

What does this mean and how do I fix it? The only thing I changed in the settings.py file was moving some variable names around. I can still successfully interact with the app with

python2.7 manage.py shell

But I can't get to it on the web, nor use the API.

EDIT: Here's my wsgi.py file:

import os

from django.core.wsgi import get_wsgi_application

os.environ.setdefault("DJANGO_SETTINGS_MODULE", "<myapp>.settings")

application = get_wsgi_application()

Solution

Python C extension modules, like numpy, are known to cause timeouts when used under mod_wsgi. There's a clear explanation of the problem (direct from the author of mod_wsgi) available at https://serverfault.com/a/514251/109598

If that sounds like it might be the cause of your problem, then the solution is probably simple - add the following to your httpd.conf:

WSGIApplicationGroup %{GLOBAL}

Be sure to restart your Apache instance after making that change.