how to use fastcgi and virtualenv?

I'm actually answering this question, since I cannot edit the wiki.

1. Setup your virtualenv directory. I'll use /var/admin/graphite as my graphite root dir, and /var/admin/graphite/PYVIRT for my virtualenv environment directory.

   $ mkdir -p /var/admin/graphite/PYVIRT
   $ virtualenv /var/admin/graphite/PYVIRT

2. activate the environment via: source /var/admin/graphite/PYVIRT/bin/activate
   # note, some shells, like zsh, require running 'rehash' so you can find the proper python and easy_install.

3. install needed packages, etc

    (PYVIRT)$ easy_install Django
    (PYVIRT)$ apt-get install python-cairo python-pyparsing memcached

4. install graphite using --root-dir=/var/admin/graphite, following the standard instructions.
    ( I used 0.9.4 for this example.)
    Note that you'll also need to use 'apt-get install python-mod-python' for the normal install script.

5. create a dispatch.fcgi script like this:

#!/var/admin/graphite/PYVIRT/bin/python

# setup the virtualenv
import os
os.environ.setdefault('PATH', '/bin:/usr/bin')
os.environ['PATH'] = '/var/admin/graphite/PYVIRT/bin:' + os.environ['PATH']
os.environ['VIRTUAL_ENV'] = '/var/admin/graphite/PYVIRT'
os.environ['PYTHON_EGG_CACHE'] = '/var/admin/graphite/PYVIRT/egg_cache'

os.chdir('/var/admin/graphite/webapp')
import sys

# Add a custom Python path.
sys.path.insert(0, "/var/admin/graphite/webapp/web")
sys.path.insert(0, "/var/admin/graphite/webapp")

# Switch to the directory of your project. (Optional.)
#os.chdir("/var/admin/graphite/webapp/web")

# Set the DJANGO_SETTINGS_MODULE environment variable.
os.environ['DJANGO_SETTINGS_MODULE'] = "settings"

from django.core.servers.fastcgi import runfastcgi
runfastcgi(method="threaded", daemonize="false")

6. create an apache virtual host config like this:

NameVirtualHost *:80

FastCgiServer /var/admin/graphite/dispatch.fcgi -processes 1 -listen-queue-depth 1000 -idle-timeout 3600

<VirtualHost *:80>
        ServerName graphite.foxmarks.com
        DocumentRoot "/var/admin/graphite/webapp"

         ScriptAliasMatch ^(.*)$ /var/admin/graphite/dispatch.fcgi$1

        <Location "/content">
                SetHandler None
        </Location>
        ErrorLog /var/admin/graphite/storage/log/webapp-error.log
        CustomLog /var/admin/graphite/storage/log/webapp-access.log common
</VirtualHost>

7. fix the carbon init script to source the PYVIRT/bin/activate script so that carbon finds proper libs.

that's it. let me know if you have questions or bugs.

-allan