When building mod_wsgi there are two things to remember if you are building on a 64-bit Linux system. My examples came from Red Hat Enterprise Linux 5 WS.
Here is the link to these and other problems:
First, When running configure make sure the –enable-shared switch is used. This will create a shared object library similar to this /usr/local/lib:
-r-xr-xr-x 1 root root 5624411 Feb 7 10:11 libpython2.6.so.1.0
You will need to add a link, so this library can be found by Apache or your web server:
lrwxrwxrwx 1 root root 19 Feb 7 10:11 libpython2.6.so -> libpython2.6.so .1.0
And finally, don’t forget to compile the library’s location into make (mod_wsgi’s build directory).
before running make install.
Building the shared library information is important, so you do not get an error like this:
Syntax error lin line 200 of /etc/httpd/conf/httpd.con Cannot load /etc/httpd/modules/mod_wsgi.so into server: libpython2.6.so.1.0: cannot open shared object file: No such file or directory
I had mistakenly thought you Apache would use environment variables to locate the shared library.
The focus of using mod_python is to load and configure in Apache’s configuration file.
Here is a typical configuration extract for mod_python:
SetHandler python-program PythonHandler django.core.handlers.modpython SetEnv DJANGO_SETTINGS_MODULE settings SetEnv PYTHON_EGG_CACHE /tmp/.python_eggs PythonOption django.root /home/amr/django/amr PythonPath "['/home/amr/django/amr/bin', '/home/amr/django', '/home/amr/django/amr', '/home/amr/django/amr/media', '/home/amr/django/amr/media/admin'] + sys.path" PythonDebug On
On the other hand, mod_wsgi is mentioned in the Apache configuration, but a lot more of the configuration is contained within the mod_wsgi handler, which you write:
WSGIScriptAlias / /usr/local/www/wsgi-scripts/wsgi_handler.py <Directory /usr/local/www/wsgi-scripts> Order allow,deny Allow from all </Directory>
Here is a working mod_wsgi handler:
import os import sys PROJECT_ROOT = os.path.realpath(os.path.dirname(__file__)) sys.path.append(PROJECT_ROOT) sys.path.append(os.path.join('/home/amr/django')) sys.path.append(os.path.join('/home/amr/django/amr')) sys.path.append(os.path.join('/home/amr/bin')) sys.path.append(os.path.join('/usr/local/www/documents/media')) sys.path.append(os.path.join('/usr/local/www/documents/media/media')) os.environ['DJANGO_SETTINGS_MODULE'] = 'amr.settings' os.environ['PYTHON_EGG_CACHE'] = '/tmp/python_egg_cache' import django.core.handlers.wsgi application = django.core.handlers.wsgi.WSGIHandler()
And finally, here is the full Apache configuration, which will allow loading css and other static documents along with the Django admin site.
Listen 8002 <VirtualHost _default_:8002> AliasMatch ^/([^/]*\.css) /usr/local/www/documents/media/$1 Alias /media/ /usr/local/www/documents/media/media/ Alias /static/ /usr/local/www/documents/media/ <Directory /usr/local/www/documents/media/> Order deny,allow Allow from all </Directory> WSGIScriptAlias / /usr/local/www/wsgi-scripts/wsgi_handler.py <Directory /usr/local/www/wsgi-scripts> Order allow,deny Allow from all </Directory> ServerAdmin firstname.lastname@example.org </VirtualHost>
Finally, the pertinent environment variables from settings.py
I chose Django for two reasons. First it was a framework, and second its back end was Python instead of another language. Also, the Django “sales pitch” appealed to me. My Django projects started with mod_python, the Apache module that allows Python code to be executed in Apache’s back end.
Almost all references to mod_python were accompanied by the advice that mod_wsgi should be used, unless this was a legacy web site that could not easily be re-written. Eventually, I came to the same conclusion as almost everyone else, and moving to mod_wsgi was not due to lack of basic Django functionality. Instead my problems were almost completely due to not understanding how to load media.
Moving from mod_python to mod_wsgi became a small project in itself.
I have been struggling a while with a Django content loading problem. Given my web site is both in production and under development, I thought it might be a good thing to take my workstation and start the conversion from mod_python to mod_wsgi. It is always a good decision not to make major changes on your production system, but I’m beginning to think it was not a good idea on my workstation, either.
I am running apache on Ubuntu 10.04 LTS, and while it’s a desktop configuration, the server configuration was installed, so I could do development work. The whole process, including getting wsgi installed as been, as I’m fond of saying, one long root canal without Novocaine.
I am determined to succeed, because I believe in the basic premise of frame-based web development.
Tonight, I’m going into a Django meetup to hear about installation — a night that’s going to be snowing and cold — only because installation and configuration is the headliner topic. I will have to see what develops.