Django, mod_wsgi, psycopg2 ImproperlyConfigured: Error loading psycopg2 module: No module named _psycopg

Question

I have a Django 1.5, Python 2.7 site running under Apache with mod_wsgi on a CentOS 6.4 server.

I have rebuilt this site using Django 1.6 and Python 3.3. Deploying it to the same server and changing the paths in httpd.conf I get the subject error. This new install works as expected using ./manage.py runserver.

Here are the two WSGI definitions from httpd.conf:

WSGIScriptAlias / /home/ccdgen/CCDGEN2/apache/wsgi.py
WSGIPythonPath         /home/ccdgen/CCDGEN2/ccdgen/ccdgen:/home/ccdgen/CCDGEN2/ccdgen:/home/ccdgen/CCDGEN2/lib/python3.3/site-packages
<Directory /home/ccdgen/CCDGEN2/ccdgen>
   <Files wsgi.py>
     Order allow,deny
     Allow from all
   </Files>
</Directory>

#WSGIScriptAlias /ccdgen /home/ccdgen/CCDGEN/apache/wsgi.py
#WSGIPythonPath /home/ccdgen/CCDGEN/mlhim/ccdgen:/home/ccdgen/CCDGEN/mlhim:/home/ccdgen/CCDGEN/lib/python2.7/site-packages
#<Directory /home/ccdgen/CCDGEN/mlhim>
#   <Files wsgi.py>
#     Order allow,deny
#     Allow from all
#   </Files>
#</Directory>

The wsgi.py file is the same on both installations:

import os
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "mlhim.settings")
from django.core.wsgi import get_wsgi_application
application = get_wsgi_application()

Any ideas? Obvious oversights? Thanks

Answer 1

The problem was that mod_wsgi was compiled for Python 2.7 and it needed to be recompiled for Python 3.3. I did not find a new mod_wsgi available anywhere as a package so I recompiled it.

Since Python 3 is an alternate install on CentOS 6.4 .configure had a difficult time producing a good Makefile, even passing the --with-python option. I needed to edit Makefile a bit after getting the information from python3.3-config --cflags and also with --ldflags options.

HTH someone in the future.

Answer 2

I had this problem recently:

ImproperlyConfigured: Error loading psycopg2 module: No module named _psycopg

... and this command was the answer:

sudo apt-get install libapache2-mod-wsgi-py3

Reference:

http://python.6.x6.nabble.com/ImproperlyConfigured-Error-loading-psycopg2-module-No-module-named-psycopg-td5044145.html

Answer 3

Try these commands Debian, Ubuntu

sudo apt-get install python-dev
sudo apt-get install libpq-dev

For RedHat Enterprise, Fedora, CentOS

sudo yum install python-devel
sudo yum install postgresql-libs

Then Install psycopg2

pip install psycopg2

Answer 4

As has been mentioned, mod_wsgi has not been compiled for python 3. One option is to use Software Collections and/or go with nginx, and "pip install uwsgi" which saves a lot of compiling and running custom packages.