Trac and mod_python

Trac 0.8 and later (not yet released) supports ​mod_python, which speeds up Trac's response times considerably and permits use of many Apache features not possible with tracd/mod_proxy.

Simple configuration

Here's a typical Trac CGI/Apache setup:

ScriptAlias /trac/myproject /path/to/python/share/trac/cgi-bin/trac.cgi
<Location /trac/myproject>
   SetEnv TRAC_ENV /var/svn/trac/myproject
</Location>

The equivalent mod_python setup is:

<Location /trac/myproject>
   SetHandler mod_python
   PythonHandler trac.ModPythonHandler
   PythonOption TracEnv /var/svn/trac/myproject
</Location>

Note: you will need to create a real physical trac/ directory (name matches the first location path segment from the above example) inside your DocumentRoot so that Trac can figure out the correct base location. That seems to be a problem (or feature?) with mod_python.

Setting up multiple projects

While the Trac mod_python handler does not yet support multiple projects directly, you can configure it so that multiple projects can be hosted, as can be seen in the following simple example:

<LocationMatch /mptrac/[[:alnum:]]+>
  SetHandler mod_python
  PythonHandler trac.ModPythonHandler
</LocationMatch>
<Location /mptrac/trac>
  PythonOption TracEnv "/var/www/projects/trac"
</Location>
<Location /mptrac/dwt>
  PythonOption TracEnv "/var/www/projects/mediatis-dwt"
</Location>

This sets up two projects. The disadvantage of the approach used here is that you need one additional <Location> directive per Trac instance. There may very well be better ways to accomplish this.

A word of warning: Don't be tempted into using the ​support for multiple python interpreters! There appears to be a problem with loading the ClearSilver library (and/or python bindings) more than once per process. When you try to use multiple interpreters, every instance other than the first instance you accessed will fail with an import error on neo_cs.