TracFastCgi
FastCGI interface allows Trac to remain resident much like with [wiki:TracModPython] or [wiki:TracModWSGI]. It is faster than external CGI interfaces which must start a new process for each request. Additionally, it is supported by much wider variety of web servers.
Note that unlike mod_python, FastCGI supports Apache SuEXEC, i.e. run with different permissions than web server running with (`mod_wsgi` supports the `WSGIDaemonProcess` with user / group parameters to achieve the same effect).
Note for Windows: Trac's FastCGI does not run under Windows, as Windows does not implement `Socket.fromfd`, which is used by `_fcgi.py`. If you want to connect to IIS, you may want to try [trac:TracOnWindowsIisAjp]/[trac:TracOnWindowsIisAjp].
PageOutline(2-3,Overview,inline)
There are two FastCGI modules commonly available for Apache: `mod_fastcgi` and `mod_fcgid` (preferred). The latter is more up-to-date.
The following sections focus on the FCGI specific setup, see also [wiki:TracModWSGI#ConfiguringAuthentication] for configuring the authentication in Apache.
Regardless of which cgi module is used, be sure the web server has executable permissions on the cgi-bin folder. While FastCGI will throw specific permissions errors, mod_fcgid will throw an ambiguous error if this has not been done. (Connection reset by peer: mod_fcgid: error reading data from FastCGI server)
`mod_fastcgi` uses `FastCgiIpcDir` and `FastCgiConfig` directives that should be added to an appropriate Apache configuration file:
Setting `FastCgiIpcDir` is optional if the default is suitable. Note that the `LoadModule` line must be after the `IfModule` group.
Configure `ScriptAlias` or similar options as described in TracCgi, but calling `trac.fcgi` instead of `trac.cgi`.
Add the following to the Apache configuration file (below the `FastCgiIpcDir` line) if you intend to set up the `TRAC_ENV` as an overall default:
Alternatively, you can serve multiple Trac projects in a directory by adding this:
Configure `ScriptAlias` (see TracCgi for details), but call `trac.fcgi` instead of `trac.cgi`. Note that slash at the end - it is important.
To set up Trac environment for `mod_fcgid` it is necessary to use `DefaultInitEnv` directive. It cannot be used in `Directory` or `Location` context, so if you need to support multiple projects, try alternative environment setup below.
A better method to specify path to Trac environment is to embed the path into `trac.fcgi` script itself. That doesn't require configuration of server environment variables, works for both FastCgi modules (and for lighttpd and CGI as well):
or
With this method different projects can be supported by using different `.fcgi` scripts with different `ScriptAliases`.
See this fcgid example config which uses a !ScriptAlias directive with trac.fcgi with a trailing / like this:
The configuration on Cherokee's side is quite simple. You will only need to know that you can spawn Trac as an SCGI process. You can either start it manually, or better yet, automatically by letting Cherokee spawn the server whenever it is down. First set up an information source in cherokee-admin with a local interpreter.
If the port was not reachable, the interpreter command would be launched. Note that, in the definition of the information source, you will have to manually launch the spawner if you use a Remote host as Information source instead of a Local interpreter.
After doing this, we will just have to create a new rule managed by the SCGI handler to access Trac. It can be created in a new virtual server, trac.example.net for instance, and will only need two rules. The default one will use the SCGI handler associated to the previously created information source. The second rule will be there to serve the few static files needed to correctly display the Trac interface. Create it as Directory rule for /common and just set it to the Static files handler and with a Document root that points to the appropriate files: $TRAC_LOCAL/htdocs/ (where $TRAC_LOCAL is a directory defined by the user or the system administrator to place local trac resources).
Note:\\ If the tracd process fails to start up, and cherokee displays a 503 error page, you might be missing the python-flup package.\\ Python-flup is a dependency which provides trac with SCGI capability. You can install it on debian based systems with:
The FastCGI front-end was developed primarily for use with alternative webservers, such as lighttpd.
lighttpd is a secure, fast, compliant and very flexible web-server that has been optimized for high-performance environments. It has a very low memory footprint compared to other web servers and takes care of CPU load.
For using `trac.fcgi`(prior to 0.11) / fcgi_frontend.py (0.11) with lighttpd add the following to your lighttpd.conf:
Note that you will need to add a new entry to `fastcgi.server` for each separate Trac instance that you wish to run. Alternatively, you may use the `TRAC_ENV_PARENT_DIR` variable instead of `TRAC_ENV` as described above, and you may set one of the two in `trac.fcgi` instead of in `lighttpd.conf` using `bin-environment` (as in the section above on Apache configuration).
Note that lighttpd has a bug related to 'SCRIPT_NAME' and 'PATH_INFO' when the uri of fastcgi.server is '/' instead of '/trac' in this example (see [trac:#2418]). This should be fixed since lighttpd 1.4.23, and you may need to add `"fix-root-scriptname" => "enable"` as parameter of fastcgi.server.
For using two projects with lighttpd add the following to your `lighttpd.conf`:
Note that field values are different. If you prefer setting the environment variables in the `.fcgi` scripts, then copy/rename `trac.fcgi`, e.g., to `first.fcgi` and `second.fcgi`, and reference them in the above settings. Note that the above will result in different processes in any event, even if both are running from the same `trac.fcgi` script.
For authentication you should enable mod_auth in lighttpd.conf 'server.modules', select auth.backend and auth rules:
Note that lighttpd (I use version 1.4.3) stopped if password file doesn't exist.
Note that lighttpd doesn't support 'valid-user' in versions prior to 1.3.16.
Conditional configuration is also useful for mapping static resources, i.e. serving out images and CSS directly instead of through FastCGI:
The technique can be easily adapted for use with multiple projects by creating aliases for each of them, and wrapping the fastcgi.server declarations inside conditional configuration blocks. Also there is another way to handle multiple projects and it's to use TRAC_ENV_PARENT_DIR instead of TRAC_ENV and use global auth, let's see an example:
Changing date/time format also supported by lighttpd over environment variable LC_TIME
For details about languages specification see [trac:TracFaq] question 2.13.
Other important information like the [wiki:TracInstall#MappingStaticResources] are useful for non-fastcgi specific installation aspects. ]
Relaunch lighttpd, and browse to `http://yourhost.example.org/trac` to access Trac.
Note about running lighttpd with reduced permissions:
If nothing else helps and trac.fcgi doesn't start with lighttpd settings `server.username = "www-data"`, `server.groupname = "www-data"`, then in the `bin-environment` section set `PYTHON_EGG_CACHE` to the home directory of `www-data` or some other directory accessible to this account for writing.
The FastCGI front-end was developed primarily for use with alternative webservers, such as LiteSpeed.
!LiteSpeed web server is an event-driven asynchronous Apache replacement designed from the ground-up to be secure, scalable, and operate with minimal resources. !LiteSpeed can operate directly from an Apache config file and is targeted for business-critical environments.
1. Please make sure you have first have a working install of a Trac project. Test install with “tracd” first.
2. Create a Virtual Host for this setup. From now on we will refer to this vhost as !TracVhost. For this tutorial we will be assuming that your trac project will be accessible via:
3. Go “!TracVhost → External Apps” tab and create a new “External Application”.
4. Optional. If you need to use htpasswd based authentication. Go to “!TracVhost → Security” tab and create a new security “Realm”.
If you don’t have a htpasswd file or don’t know how to create the entries within one, go to http://sherylcanter.com/encrypt.php, to generate the user:password combos.
5. Go to “!PythonVhost → Contexts” and create a new “FCGI Context”.
6. Modify `/fullpathto/mytracproject/conf/trac.ini`
7. Restart !LiteSpeed, “lswsctrl restart”, and access your new Trac project at:
Nginx is able to communicate with FastCGI processes, but can not spawn them. So you need to start FastCGI server for Trac separately.
1. Nginx configuration with basic authentication handled by Nginx - confirmed to work on 0.6.32
2. Modified trac.fcgi:
3. reload nginx and launch trac.fcgi like that:
The above assumes that:
* There is a user named 'trac' for running trac instances and keeping trac environments in its home directory. * `/home/trac/instance` contains a trac environment * `/home/trac/htpasswd` contains authentication information * `/home/trac/run` is owned by the same group the nginx runs under * and if your system is Linux the `/home/trac/run` has setgid bit set (`chmod g+s run`) * and patch from ticket #T7239 is applied, or you'll have to fix the socket file permissions every time
Unfortunately nginx does not support variable expansion in fastcgi_pass directive. Thus it is not possible to serve multiple trac instances from one server block.
If you worry enough about security, run trac instances under separate users.
Another way to run trac as a FCGI external application is offered in ticket #T6224
See also: TracGuide, TracInstall, [wiki:TracModWSGI], [wiki:TracCgi], [wiki:TracModPython], [trac:TracNginxRecipe]