Trac with FastCGI
FastCGI interface allows Trac to remain resident much like with mod_python. It is faster than external CGI interfaces which must start a new process for each request. However, unlike mod_python, FastCGI supports Apache SuEXEC, i.e. run with different permissions than web server. Additionally, it is supported by much wider variety of web servers.
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 AJP].
There are two FastCGI modules commonly available for Apache: `mod_fastcgi` and
`mod_fcgid` (preferred). The latter is more up-to-date.
`mod_fastcgi` uses `FastCgiIpcDir` and `FastCgiConfig` directives that should be added to an appropriate Apache configuration file:
# Enable fastcgi for .fcgi files
- (If you’re using a distro package for mod_fcgi, something like
- this is probably already present)
AddHandler fastcgi-script .fcgi
FastCgiIpcDir /var/lib/apache2/fastcgi
LoadModule fastcgi_module /usr/lib/apache2/modules/mod_fastcgi.so
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`.
You can set up the `TRAC_ENV` as an overall default:
FastCgiConfig -initial-env TRAC_ENV=/path/to/env/trac
Or you can serve multiple Trac projects in a directory like:
FastCgiConfig -initial-env TRAC_ENV_PARENT_DIR=/parent/dir/of/projects
Configure `ScriptAlias` (see TracCgi for details), but call `trac.fcgi`
instead of `trac.cgi`. Note that slash at the end – it is important.
ScriptAlias /trac /path/to/www/trac/cgi-bin/trac.fcgi/
To setup 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.
DefaultInitEnv TRAC_ENV /path/to/env/trac/
A better method to specify path to Trac environment it 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):
import os
os.environ['TRAC_ENV'] = "/path/to/projectenv"
or
import os
os.environ['TRAC_ENV_PARENT_DIR'] = "/path/to/project/parent/dir"
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:
ScriptAlias / /srv/tracsite/cgi-bin/trac.fcgi/
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.
Host:
localhost:4433
Interpreter:
/usr/bin/tracd —single-env —daemonize —protocol=scgi —hostname=localhost —port=4433 /path/to/project/
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 /chrome/common and just set it to the Static files handler and with a Document root that points to the appropriate files: /usr/share/trac/htdocs/
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:
#var.fcgi_binary="/usr/bin/python /path/to/fcgi_frontend.py" # 0.11 if installed with easy_setup, it is inside the egg directory
var.fcgi_binary="/path/to/cgi-bin/trac.fcgi" # 0.10 name of prior fcgi executable
fastcgi.server = ("/trac" =>
(“trac” =>
(“socket” => “/tmp/trac-fastcgi.sock”,
“bin-path” => fcgi_binary,
“check-local” => “disable”,
“bin-environment” =>
(“TRAC_ENV” => “/path/to/projenv”)
)
)
)
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 #Trac2418. 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`:
fastcgi.server = ("/first" =>
("first" =>
("socket" => "/tmp/trac-fastcgi-first.sock",
"bin-path" => fcgi_binary,
"check-local" => "disable",
"bin-environment" =>
("TRAC_ENV" => "/path/to/projenv-first")
)
),
"/second" =>
("second" =>
("socket" => "/tmp/trac-fastcgi-second.sock",
"bin-path" => fcgi_binary,
"check-local" => "disable",
"bin-environment" =>
("TRAC_ENV" => "/path/to/projenv-second")
)
)
)
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.
#!div class=important
'''Note''' It's very important the order on which server.modules are loaded, if mod_auth is not loaded '''BEFORE''' mod_fastcgi, then the server will fail to authenticate the user.
For authentication you should enable mod_auth in lighttpd.conf ‘server.modules’, select auth.backend and auth rules:
server.modules = (
...
"mod_auth",
...
)
auth.backend = “htpasswd”
- Separated password files for each project
- See “Conditional Configuration” in
- http://trac.lighttpd.net/trac/file/branches/lighttpd-merge-1.4.x/doc/configuration.txt
$HTTP[“url”] =~ “^/first/” {
auth.backend.htpasswd.userfile = “/path/to/projenv-first/htpasswd.htaccess”
}
$HTTP[“url”] =~ “^/second/” {
auth.backend.htpasswd.userfile = “/path/to/projenv-second/htpasswd.htaccess”
}
- Enable auth on trac URLs, see
- http://trac.lighttpd.net/trac/file/branches/lighttpd-merge-1.4.x/doc/authentication.txt
auth.require = (“/first/login” =>
(“method” => “basic”,
“realm” => “First project”,
“require” => “valid-user”
),
“/second/login” =>
(“method” => “basic”,
“realm” => “Second project”,
“require” => “valid-user”
)
)
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:
# Aliasing functionality is needed
server.modules += ("mod_alias")
- Setup an alias for the static resources
alias.url = (“/trac/chrome/common” => “/usr/share/trac/htdocs”)
- Use negative lookahead, matching all requests that ask for any resource under /trac, EXCEPT in
- /trac/chrome/common, and use FastCGI for those
$HTTP[“url”] =~ “^/trac(?!/chrome/common)” {
- Even if you have other fastcgi.server declarations for applications other than Trac, do NOT use += here
fastcgi.server = (“/trac” =>
(“trac” =>
(“socket” => “/tmp/trac-fastcgi.sock”,
“bin-path” => fcgi_binary,
“check-local” => “disable”,
“bin-environment” =>
(“TRAC_ENV” => “/path/to/projenv”)
)
)
)
}
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:
# This is for handling multiple projects
alias.url = ( "/trac/" => "/path/to/trac/htdocs/" )
fastcgi.server += (“/projects” =>
(“trac” =>
(
“socket” => “/tmp/trac.sock”,
“bin-path” => fcgi_binary,
“check-local” => “disable”,
“bin-environment” =>
(“TRAC_ENV_PARENT_DIR” => “/path/to/parent/dir/of/projects/” )
)
)
)
#And here starts the global auth configuration
auth.backend = “htpasswd”
auth.backend.htpasswd.userfile = “/path/to/unique/htpassword/file/trac.htpasswd”
$HTTP[“url”] =~ “^/projects/.*/login$” {
auth.require = (“/” =>
(
“method” => “basic”,
“realm” => “trac”,
“require” => “valid-user”
)
)
}
Changing date/time format also supported by lighttpd over environment variable LC_TIME
fastcgi.server = ("/trac" =>
("trac" =>
("socket" => "/tmp/trac-fastcgi.sock",
"bin-path" => fcgi_binary,
"check-local" => "disable",
"bin-environment" =>
("TRAC_ENV" => "/path/to/projenv",
"LC_TIME" => "ru_RU")
)
)
)
For details about languages specification see [trac:TracFaq TracFaq] question 2.13.
Other important information like this updated TracInstall page, and this are useful for non-fastcgi specific installation aspects.
If you use trac-0.9, read about small bug
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:http://yourdomain.com/trac/
Name: MyTracFCGI
Address: uds://tmp/lshttpd/mytracfcgi.sock
Max Connections: 10
Environment: TRAC_ENV=/fullpathto/mytracproject/ <--- path to root folder of trac project
Initial Request Timeout (secs): 30
Retry Timeout (secs): 0
Persistent Connection Yes
Connection Keepalive Timeout: 30
Response Bufferring: No
Auto Start: Yes
Command: /usr/share/trac/cgi-bin/trac.fcgi <--- path to trac.fcgi
Back Log: 50
Instances: 10
DB Type: Password File
Realm Name: MyTracUserDB <--- any name you wish and referenced later
User DB Location: /fullpathto/htpasswd <--- path to your htpasswd file
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”.URI: /trac/ <--- URI path to bind to python fcgi app we created
Fast CGI App: [VHost Level] MyTractFCGI <--- select the trac fcgi extapp we just created
Realm: TracUserDB <--- only if (4) is set. select realm created in (4)
#find/set base_rul, url, and link variables
base_url = http://yourdomain.com/trac/ <--- base url to generate correct links to
url = http://yourdomain.com/trac/ <--- link of project
link = http://yourdomain.com/trac/ <--- link of graphic logo
http://yourdomain.com/trac/
server {
listen 10.9.8.7:443;
server_name trac.example;
ssl on;
ssl_certificate /etc/ssl/trac.example.crt;
ssl_certificate_key /etc/ssl/trac.example.key;
ssl_session_timeout 5m;
ssl_protocols SSLv2 SSLv3 TLSv1;
ssl_ciphers ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP;
ssl_prefer_server_ciphers on;
# (Or ``^/some/prefix/(.*)``.
if ($uri ~ ^/(.*)) {
set $path_info /$1;
}
# You can copy this whole location to ``location [/some/prefix]/login``
# and remove the auth entries below if you want Trac to enforce
# authorization where appropriate instead of needing to authenticate
# for accessing the whole site.
# (Or ``location /some/prefix``.)
location / {
auth_basic "trac realm";
auth_basic_user_file /home/trac/htpasswd;
# socket address
fastcgi_pass unix:/home/trac/run/instance.sock;
# python - wsgi specific
fastcgi_param HTTPS on;
## WSGI REQUIRED VARIABLES
# WSGI application name - trac instance prefix.
# (Or ``fastcgi_param SCRIPT_NAME /some/prefix``.)
fastcgi_param SCRIPT_NAME "";
fastcgi_param PATH_INFO $path_info;
## WSGI NEEDED VARIABLES - trac warns about them
fastcgi_param REQUEST_METHOD $request_method;
fastcgi_param SERVER_NAME $server_name;
fastcgi_param SERVER_PORT $server_port;
fastcgi_param SERVER_PROTOCOL $server_protocol;
fastcgi_param QUERY_STRING $query_string;
# for authentication to work
fastcgi_param AUTH_USER $remote_user;
fastcgi_param REMOTE_USER $remote_user;
}
}
#!/usr/bin/env python
import os
sockaddr = '/home/trac/run/instance.sock'
os.environ['TRAC_ENV'] = '/home/trac/instance'
try:
from trac.web.main import dispatch_request
import trac.web._fcgi
fcgiserv = trac.web._fcgi.WSGIServer(dispatch_request,
bindAddress = sockaddr, umask = 7)
fcgiserv.run()
except SystemExit:
raise
except Exception, e:
print 'Content-Type: text/plain\r\n\r\n',
print 'Oops...'
print
print 'Trac detected an internal error:'
print
print e
print
import traceback
import StringIO
tb = StringIO.StringIO()
traceback.print_exc(file=tb)
print tb.getvalue()
trac@trac.example ~ $ ./trac-standalone-fcgi.py
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, ModWSGI, [wiki:TracCgi CGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]