Deploying web page in python using PYLONS.

This approach is simple and painless. (It differs from the one on pylonsbooks much)  It doesn’t use python environment (pyt-env) embedded in userspace etc. ROOT access is required to install pylons in this manner.
Ubuntu version: 10.10 Server

1. Install apache server
   
   aptitude install apache2
   
   
2. Check if it works:  127.0.0.1  should give you: “It works!”
   
3. Install  Python WSGI adapter module for Apache
   
   aptitude install libapache2-mod-wsgi
   
   
   
4. Disable the default apache site:
   
   a2dissite 000-default
   
   (or any other site in: /etc/apache2/sites-enabled)
5. Install easy_install for python

   apt-get install python-setuptools python-dev build-essential

   
   
6. Set the proxy if necessary:
   
   export HTTP_PROXY=http://user:pass@10.60.30.248:8080/
   
   
7. easy_install paste
   
8. aptitude install python-pastedeploy
   
9. easy_install SQLAlchemy
   
10. easy_install Pylons
    
11. add www-data user to your user group
    
    usermod -a -G simplesite www-data
    
    
12. set debug = false in your development.ini
    
    [DEFAULT]
    debug = false
    
    
13. move you application to: /usr/lib/pymodules/python2.6

/etc/apache2/sites-available/OBIAD:

<VirtualHost *>     ServerName etiopia     ServerAlias etiopia     # Logfiles     ErrorLog  /var/log/apache2/error.log     CustomLog /var/log/apache2/access.log combined     # Setup mod_wsgi     WSGIScriptAlias / /home/ubuntu/OBIAD/dispatch.wsgi     <Directory /home/ubuntu/OBIAD>     Order deny,allow     Allow from all     </Directory> </VirtualHost> a2ensite OBIAD

OBIAD is the site name. It can be any name instead of OBIAD.
/home/ubuntu/OBIAD/dispatch.wsgi:

#Load the Pylons application from paste.deploy import loadapp application = loadapp('config:/home/ubuntu/OBIAD/development.ini')

Place your application in the following directory, so that python can find it: /usr/lib/pymodules/python2.6
Restart apache with:

/etc/init.d/apache2 restart

Look for any errors in: /var/log/apache2/error.log
While starting apache I had the following error. Despite this everything worked fine (There was a bug and we can ignore this error):

[error] Exception KeyError: KeyError(140024401471296,) in <module 'threading' from '/usr/lib/python2.6/threading.pyc'> ignored [error] Exception KeyError: KeyError(140024401471296,) in <module 'threading' from '/usr/lib/python2.6/threading.pyc'> ignored [notice] caught SIGTERM, shutting down [warn] mod_wsgi: Compiled for Python/2.6.5. [warn] mod_wsgi: Runtime using Python/2.6.6. [notice] Apache/2.2.16 (Ubuntu) mod_wsgi/3.2 Python/2.6.6 configured -- resuming normal operations

Errors you may encounter:
ImportError: No module named paste.deploy –> install paste with “easy_install paste”
ImportError: No module named deploy –> aptitude install python-pastedeploy
OSError: File '/home/ubuntu/OBIAD/development.ini' not found –> copy your *.ini from you application to the destination directory
DistributionNotFound: dinner –> you haven’t copied your application to destination directory (/usr/lib/pymodules/python2.6/)
DistributionNotFound: SQLAlchemy>=0.5 –>  easy_install SQLAlchemy


Proxy causing errors. If you see any of the messages:

[error] [client 10.60.1.248] IOError: failed to write data [error] [client 10.60.1.248] mod_wsgi (pid=7892): Exception occurred processing WSGI script '/home/ubuntu/OBIAD/dispatch.wsgi'. it’s probably your proxy causing problems. Mod_wsgi does not do well with proxies unfortunately.