Django + Apache + Windows WSGIDaemonProcess Alternative

Question

After setting up a django site and running on the dev server, I have finally gotten around to figuring out deploying it in a production environment using the recommended mod_wsgi/apache22. I am currently limited to deploying this on a Windows XP machine.

My problem is that several django views I have written use the python subprocess module to run programs on the filesystem. I keep getting errors when running the subprocess.Popen I have seen several SO questions that have asked about this, and the accepted answer is to use WSGIDaemonProcess to handle the problem (due to permissions of the apache user, I believe).

The only problem with this is that WSGIDaemonProcess is not available for mod_wsgi on Windows. Is there any way that I can use mod_wsgi/apache/windows/subprocess together?

Answer 1

It's not a good idea to open subprocesses from within mod_wsgi, anyway.

An alternative (and a common one) is to use mod_proxy on the apache side and forward requests from apache to a WSGI server running Django. This has the advantage of moving the python thread(s) out of apache's memory space There are dozens of options for wsgi servers; tornado and gunicorn are two popular choices, and gunicorn integrates* with Django.

*by integrate I just mean it provides a manage.py command if you add it to INSTALLED_APPS.

Answer 2

I ran into a couple of issues trying to use subprocess under this configuration. Since I am not sure what specifically you had trouble with I can share a couple of things that were not easy for me to solve but in hindsight seem pretty trivial.

1. I was receiving permissions related errors when trying to execute an application. I searched quite a bit but was having a hard time finding Windows specific answers. This one was obvious: I changed the user under which Apache runs to a user with higher permissions. (Note, there are security implications with that so you want to be sure you understand what you are getting in to).
2. Django (depending on your configuration) may store strings as Unicode. I had a command line application I was trying to run with some parameters from my view which was crashing despite having the correct arguments passed in. After a couple hours of frustration I did a type(args) which returned <type 'unicode'> rather than my expected string. A quick conversion resolved that issue.