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This page documents the 1.4 (latest stable) release. Documentation for other releases can be found here.
Trac and mod_python
Trac supports mod_python, which speeds up Trac's response times considerably, especially compared to TracCgi, and permits use of many Apache features not possible with tracd/mod_proxy.
Attention: These instructions apply to Trac version 0.9. If you're installing Trac 0.8.x, please see a previous version of this page. If you're upgrading from 0.8.x to 0.9, please read the upgrade instructions.
Be sure to grab mod_python 3.1.3 and later for SetHandler mod_python directive to work. Also, older versions may generate an internal error (see #1090)
What is the preferred MPM method, or does it matter (worker or prefork)
Simple configuration
If you just installed mod_python, you may have to add a line to load the module in the Apache configuration:
LoadModule python_module modules/mod_python.so Note: On FreeBSD 6.1 and Apache 2.2.x use LoadModule python_module libexec/apache22/mod_python.so
A simple setup of Trac on mod_python looks like this:
<Location /projects/myproject> SetHandler mod_python PythonHandler trac.web.modpython_frontend PythonOption TracEnv /var/trac/myproject PythonOption TracUriRoot /projects/myproject </Location>
Notes:
- The option
TracUriRoot
may or may not be necessary in your setup. Try your configuration with out it, and if the URLs produced by Trac look wrong or if Trac does not seem to recognize the URLs correctly, add theTracUriRoot
option. You will notice that theLocation
andTracUriRoot
have the same path. - Your web server may need the aplitiy to write to files in the
TracEnv
directory on your server. You can change these by using the chown utility on *nix based servers. - You can test your mod_python installation by adding the following to your httpd.conf. You should remove this when you are done testing for security reasons.
<Location /mpinfo> SetHandler mod_python PythonHandler mod_python.testhandler </Location>
Configuring authentication works the same as for CGI:
<Location "/projects/myproject/login"> AuthType Basic AuthName "myproject" AuthUserFile /var/trac/myproject/.htpasswd Require valid-user </Location>
If the Trac installation isn't installed in your Python path, you'll have to tell Apache where to find the Trac mod_python handler using the PythonPath
directive:
<Location /projects/myproject> ... PythonPath "sys.path + ['/path/to/trac']" ... </Location>
Setting up multiple projects
The Trac mod_python handler supports a configuration option similar to Subversion's SvnParentPath
, called TracEnvParentDir
:
<Location /projects> SetHandler mod_python PythonHandler trac.web.modpython_frontend PythonOption TracEnvParentDir /var/trac PythonOption TracUriRoot /projects </Location>
When you request the /projects
URL, you will get a listing of all subdirectories of the directory you set as TracEnvParentDir
. Selecting any project in the list will bring you to the corresponding Trac environment.
If you don't want to have the subdirectory listing as your projects home page you can use a
<LocationMatch "/.+/">
This will instruct Apache to use mod_python for all locations different from root while having the possibility of placing a custom home page for root in your DocumentRoot folder.
You can also use the same authentication realm for all of the projects using a <LocationMatch>
directive:
<LocationMatch "/projects/[^/]+/login"> AuthType Basic AuthName "Trac" AuthUserFile /var/trac/.htpasswd Require valid-user </LocationMatch>
Virtual Host Configuration
Below is the sample configuration required to set up your trac as a virtual server (i.e. when you access it at the URLs like http://trac.mycompany.com):
<VirtualHost * > DocumentRoot /var/trac/myproject ServerName trac.mycompany.com <Location /> SetHandler mod_python PythonHandler trac.web.modpython_frontend PythonOption TracEnv /var/trac/myproject PythonOption TracUriRoot / </Location> <Location /login> AuthType Basic AuthName "MyCompany Trac Server" AuthUserFile /var/trac/myproject/.htpasswd Require valid-user </Location> </VirtualHost>
If your images and CSS are not applying properly add this within the VirtualHost directives
Alias /trac /usr/share/trac/htdocs <LocationMatch /trac/> SetHandler None </LocationMatch>
For a virtual host that supports multiple projects replace "TracEnv
" /var/trac/myproject with "TracEnvParentDir
" /var/trac/
Troubleshooting
'Server Error' Page Displayed
Assuming you are confident that mod_python is installed and working properly (An example of a simple test setup can be found here: http://www.dscpl.com.au/articles/modpython-001.html), if you get the following error in your browser:
The server encountered an internal error and was unable to complete your request. Either the server is overloaded or there was an error in a CGI script.
- And you get the following entries in your Apache error log:
...File "/usr/lib64/python2.3/site-packages/mod_python/apache.py", line 287, in HandlerDispatch\n log=debug) ...PythonHandler trac.web.modpython_frontend: File "/usr/lib64/python2.3/site-packages/mod_python/apache.py", line 454, in import_module\n f, p, d = imp.find_module(parts[i], path) ... PythonHandler trac.web.modpython_frontend: ImportError: No module named trac
Make sure the 'trac' directory that was created during installation has the appropriate permissions in order for the user your web server runs under to 'see' the files contained in it. This directory will be in the 'site-packages' directory of your platform's installation. A 'chmod -R 755 ./trac' resolved the issue for me. Modify as necessary for your security preferences.
- And you get the following entries in your Apache error log:
... ...PythonHandler trac.web.modpython_frontend: File "/lib/python2.4/site-packages/trac/db.py", line 211, in _rollback_on_error\n return function(self, *args, **kwargs) ...PythonHandler trac.web.modpython_frontend: OperationalError: unsupported file format
It's probably due to that you have a mod_php module in apache with SQLite support compiled into it. Unless one configures mod_php with "—without-sqlite" it will be compiled with PHP's internal SQLite-support, which is SQLite 2.x. This will confuse apache when Trac, and mod_python, dynamically tries to load another version of the SQLite library. Most probably the same version the SQLite database is constructed by, why the SQLite 2.x version included in mod_php gives the above error. Solution is either to unload mod_php or to compile mod_php without sqlite-support.
Form submission problems
If you're experiencing problems submitting some of the forms in Trac (a common problem is that you get redirected to the start page after submission), check whether your DocumentRoot
contains a folder or file with the same path that you mapped the mod_python handler to. For some reason, mod_python gets confused when it is mapped to a location that also matches a static resource.
Using .htaccess
Although it may seem trivial to rewrite the above configuration as a directory in your document root with a .htaccess
file, this does not work. Apache will append a "/" to any Trac URLs, which interferes with its correct operation.
It may be possible to work around this with mod_rewrite, but I failed to get this working. In all, it is more hassle than it is worth. Stick to the provided instructions. :)
Win32 Issues
Don't feel like compiling the source? Windows installers are available at the following URLs. Make sure you grab an installer which works with your version of Python: http://www.apache.org/dist/httpd/modpython/win/3.2.7/ or http://www.lehuen.com/nicolas/download/mod_python/
If you run trac with mod_python < 3.2 on Windows, uploading attachments will not work. This problem which is discussed in #554 is resolved in mod_python > 3.1.4 so please upgrade mod_python to fix this.
OS X issues
When using mod_python on OS X you will not be able to restart Apache using apachectl restart
. This is apparently fixed in mod_python 3.2, but there's also a patch available for earlier versions here.
SELinux issues
If Trac reports something like: Cannot get shared lock on db.lock The security context on the repository may need to be set:
chcon -R -h -t httpd_sys_content_t PATH_TO_REPOSITORY
See also http://subversion.tigris.org/faq.html#reposperms
FreeBSD issues
Pay attention to the version of installed mod_python and sqlite. Ports have both the new and old ones, but earlier versions of pysqlite and mod_python won't integrate as first require threaded support in python, and the second require threadless.
Also, seems like in FreeBSD some environment(maybe ldconfig) update is required right after installation of trac for trac-admin actually started working. I've missed the exact requirement, but noticed that immediately after installation trac-admin refused to do initenv, but after I relogged in to different shell - all worked perfectly.
Using /trac
root URL
If you wish your trac to be at http://example.com/trac, the default config will not display images or CSS correctly, and the config must be changed.
/chrome
is configurable (and infact needs to be changed) in /var/trac/myproject/conf/trac.ini
[trac] ... htdocs_location = /trac/chrome/
Then in the VirtualHost directives
Alias /trac/chrome /usr/share/trac/htdocs <LocationMatch /trac/chrome/> SetHandler None </LocationMatch>
See also TracGuide, TracInstall, TracCgi, TracFastCgi, TracMultipleProjectsSVNAccess