django-virtualenv-apache-mod_wsgi


django-virtualenv-apache-mod_wsgi

Django virtualenv Apache2 mod_wsgi

By the end of this article you will know how to deploy a Django web
application using a python virtualenv, using an Apache2 webserver with
mod_wsgi.

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Why use wsgi and virtualenv?

-   I also host pylons applications using mod_wsgi and apache2 and
    mod_python is incompatible.
-   mod_wsgi is fast.
-   I don’t want my public site-packages library conflicting with other
    applications.

.. contents::

Install virtualenv

1.  Install Setup tools:

    .. code-block :: bash

    $ sudo apt-get install python-setuptools memcached

2.  Install virtualenv:

    .. code-block :: bash

    $ sudo easy_install virtualenv

Create a virtualenv

1.  Move to the directory where you want to create the virtualenv:

    .. code-block :: bash

    $ cd /www/lostquery.com

2.  Create python environment:

    .. code-block :: bash

    $ virtualenv –no-site-packages virtpy

Install Django

1.  Activate the virtualenv:

    .. code-block :: bash

    $ source virtpy/bin/activate

2.  The shell should have changed to (virtpy) $ . Run this command to
    install django to the virtualenv:

    .. code-block :: bash

    # I know this version works… $ easy_install django==1.3.1

3.  Install any dependencies you will need to the virtualenv:

    .. code-block :: bash

    $ easy_install MySQL-python markdown html5lib modwsgideploy
    python-openid South python-memcached

Install and configure the Django web application

1.  Get the sourcecode:

    .. code-block :: bash

    $ svn co http://svn.osqa.net/svnroot/osqa/trunk

2.  Configure the application:

    .. code-block :: bash

    $ cd trunk

    $ cp settings_local.py.dist settings_local.py

    $ vi settings_local.py

3.  You must tell the Django’s application what database to use. Also
    configure memcached:

    .. code-block :: python

    # database settings DATABASE_NAME = ‘databasename’ # Or path to
    database file if using sqlite3. DATABASE_USER = ‘username’ # Not
    used with sqlite3. DATABASE_PASSWORD = ‘p@ssw0rd’ # Not used with
    sqlite3. DATABASE_ENGINE = ‘mysql’ #mysql, etc DATABASE_HOST =
    ‘localhost’ DATABASE_PORT = ’’

    # memcached settings (osqa is slow as dirt without this)
    CACHE_BACKEND = ‘memcached://127.0.0.1:11211/’

4.  Give apache access to a few directories, /trunk/log and
    /trunk/forum/upfiles:

    .. code-block :: bash

    $ chmod 777 log $ chmod 777 forum/upfiles

5.  Create the database
    (example syntax to create a mySQL database) <http://www.foxhop.net/mySQL#create-database>_.

    Let the django application build the tables in the new database:

    .. code-block :: bash

    $ python manage.py syncdb –all $ python manage.py migrate forum
    –fake

Configure Apache2 VirtualHost

1.  Turn on mod_rewrite:

    .. code-block :: bash

    $ a2enmod rewrite

2.  Create a sites-available vhost apache2 file:

    .. code-block :: bash

    $ sudo vi /etc/apache2/sites-available/007-lostquery

3.  Setup the host file:

    .. code-block :: apache :linenos:

    #lostquery.com

    #Djangos embeded mod_wsgi <VirtualHost *:80> ServerName
    lostquery.com ServerAlias www.lostquery.com ServerAdmin
    admin@admin.com

           # ReWrite URL to WWW
           RewriteEngine On
           RewriteCond %{HTTP_HOST} ^www.lostquery.com
           RewriteRule (.*) http://lostquery.com$1 [R=301,L]

           # Log Files
           ErrorLog /var/log/apache2/error-lostquery.log
           CustomLog /var/log/apache2/access-lostquery.log combined

           # Prevent django from serving static files
           DocumentRoot /www/lostquery.com/trunk/forum
           Alias /m/ /www/lostquery.com/trunk/forum/skins/
           Alias /upfiles/ /www/lostquery.com/trunk/forum/upfiles/
           <Directory /www/lostquery.com/trunk/forum/skins>
               Order allow,deny
               Allow from all
           </Directory>

           # Setup mod_wsgi
           WSGIDaemonProcess lostquery display-name=lostquery user=www-data processes=2 threads=15
           WSGIScriptAlias / /www/lostquery.com/mod_wsgi/dispatch.wsgi

Configure mod_wsgi

1.  Create the egg-cache directory:

    .. code-block :: bash

    $ mkdir /www/lostquery.com/mod_wsgi

    $ mkdir /www/lostquery.com/mod_wsgi/egg-cache

2.  Create the wsgi dispatch file:

    .. code-block :: bash

    $ vi /www/lostquery.com/mod_wsgi/dispatch.wsgi

3.  Setup the wsgi dispatch file:

    .. code-block :: python :linenos:

    import os import sys sys.stdout = sys.stderr # Add the virtual
    Python environment site-packages directory to the path import site
    site.addsitedir(‘/www/lostquery.com/virtpy/lib/python2.6/site-packages’)

    # Avoid [Errno 13] Permission denied: '/var/www/.python-eggs'
    messages
    import os os.environ[‘PYTHON_EGG_CACHE’] =
    ‘/www/lostquery.com/mod_wsgi/egg-cache’

    #If your project is not on your PYTHONPATH by default you can add
    the following sys.path.append(‘/www/lostquery.com/trunk’)
    os.environ[‘DJANGO_SETTINGS_MODULE’] = ‘settings’

    import django.core.handlers.wsgi application =
    django.core.handlers.wsgi.WSGIHandler()

Enable the Virtual Host and reload Apache2

1.  Reset apache2 so that it reads in the new config files:

    .. code-block :: bash

    $ a2ensite lostquery

    $ sudo service apache2 reload

fritzvd — Sep 28, 2011 11:31 pm

Hi,

Thanks this is great and exhaustive. Helped me host my django. One
question though, I usually do this: Create sites and put them in:
sites-available. Reload apache2 for a graceful restart. Call them/switch
on:

    a2ensite lostquery

    /etc/init.d/apache2 reload

Is there any special reason why you don’t do this?

Fritz

foxhop — Sep 29, 2011 05:00 pm

@fritzvd

I have recently started using the a2ensite method that you described.

Thanks for your input. I have adjusted the tutorial. Feel free to adjust
anything you feel need work!

Foxhop