Cody Taylor

After writing the backend for a new web app in python I went to start working on the Django portion. I was planning on hosting this application with a Dreamhost shared hosting plan which already has Python 2.5 installed. After trying unsuccessfully to install some new middleware with easy_install, I started looking for a solution that gives me more control over what I want to do with Python without having to purchase dreamhost vps hosting. It seems that you can set up a virtual python install in your home directory and it was surprisingly easy. I’ve only had the need to use this virtual python install on Dreamhost, which is using Debian, but I can’t see any reason why it wouldn’t work on other environments.

Note that this is completely unnecessary if you have root access.

Assuming you already have a shell account and you are ssh’d in, execute these commands to install your virtual python environment:

$ wget http://peak.telecommunity.com/dist/virtual-python.py 
$ python virtual-python.py

Those commands copy the Python binary to your /home/user/bin directory and sets up symbolic links to the system wide libraries. This means that the ~/bin/python executable will have access to the same libraries as the system Python but that any extra installed software will not affect the system wide Python install.

Next you should add the ~/bin directory to your PATH by adding this block to your .bash_profile:

 if [ -d ~/bin ] ; then     
    PATH=~/bin:"${PATH}" 
fi 

You’ll have to log out and back in for this to take effect.
After you’re logged back in, run these commands to install easy_setup:

$ wget http://peak.telecommunity.com/dist/ez_setup.py 
$ python ez_setup.py 

Now you should be able to install whatever you want using easy_install. The first thing I did was install django-db-log using this command:
$ easy_install django-db-log

Django is a high level python web framework that I’ve been hearing a lot about lately. I decided to try it out this weekend.
It took a little reading to get up and running so I documented the steps I took so others can get up and running a little more quickly.

sudo apt-get install django
django-admin –version

Create the appropriate directories and start the django project.

For no real reason I decided to put my new projects in /var/django.
sudo mkdir /var/django
sudo chmod 755 /var/django
cd /var/django
django-admin startproject mysite
cd mysite
mkdir apache

It seems that mod-wsgi is the best way to serve up python web apps due to mod_python being a little outdated. Note that django does come with a built in webserver that is really easy to get going. So if you’re just planning on evaluating the framework and not actually do any production aplications then that would be the way to go. mod_wsgi is an Apache module which can be used to host Python applications.

Install the module:
sudo apt-get install libapache2-mod-wsgi

Now for the configuration. It took me a few tries to get this right.
For now I just put my django site on port 8080 so I can play around without it being public to anyone else.

In the /var/django/mysite/apache directory I created a file called django.wsgi and put this in it:

import os, sys
apache_configuration= os.path.dirname(__file__)
project = os.path.dirname(apache_configuration)
sys.path.append(‘/var/django’)
os.environ[‘DJANGO_SETTINGS_MODULE’] = ‘mysite.settings’
import django.core.handlers.wsgi
application = django.core.handlers.wsgi.WSGIHandler()

Make sure that the sys.path.append line contains the directory above the project directory. This one took me awhile to figure out.
I was getting this error until I got it right.

[Sat May 30 15:33:24 2009] [error] [client 127.0.0.1]     raise ImportError, “Could not import settings ‘%s’ (Is it on sys.path? Does it have syntax errors?): %s” % (self.SETTINGS_MODULE, e)
[Sat May 30 15:33:24 2009] [error] [client 127.0.0.1] ImportError: Could not import settings ‘mysite.settings’ (Is it on sys.path? Does it have syntax errors?): No module named mysite.settings

Next I added a new virtual host in my sites-enabled folder like this:

<VirtualHost *:808http://localhost:8080/0>
ServerAdmin root@mysite.com
ServerName mysite.com
ServerAlias mysite.com
<Directory /var/django/mysite/apache>
Allow from all
</Directory>

WSGIDaemonProcess www-data
WSGIProcessGroup www-data
WSGIScriptAlias / /var/django/mysite/apache/django.wsgi
</VirtualHost>

After restarting apache :
sudo /etc/init.d/apache2 restart

I got an “It Worked” page when I point my browser to http://localhost:8080/

Of course this doesn’t allow you to use a database in your applications yet but it’s a start.