Changes between Initial Version and Version 1 of TracModWSGI

10/28/2013 11:16:28 AM (10 years ago)



  • TracModWSGI

    v1 v1  
     1= Trac and mod_wsgi =
     4[ mod_wsgi] is an Apache module for running WSGI-compatible Python applications directly on top of the Apache webserver. The mod_wsgi adapter is written completely in C and provides very good performances.
     8== The `trac.wsgi` script
     10Trac can be run on top of mod_wsgi with the help of the following application script, which is just a Python file, though usually saved with a `.wsgi` extension).
     12=== A very basic script
     13In its simplest form, the script could be:
     16import os
     18os.environ['TRAC_ENV'] = '/usr/local/trac/mysite'
     19os.environ['PYTHON_EGG_CACHE'] = '/usr/local/trac/mysite/eggs'
     21import trac.web.main
     22application = trac.web.main.dispatch_request
     25The `TRAC_ENV` variable should naturally be the directory for your Trac environment (if you have several Trac environments in a directory, you can also use `TRAC_ENV_PARENT_DIR` instead), while the `PYTHON_EGG_CACHE` should be a directory where Python can temporarily extract Python eggs.
     27=== A more elaborate script
     29If you're using multiple `.wsgi` files (for example one per Trac environment) you must ''not'' use `os.environ['TRAC_ENV']` to set the path to the Trac environment. Using this method may lead to Trac delivering the content of another Trac environment, as the variable may be filled with the path of a previously viewed Trac environment.
     31To solve this problem, use the following `.wsgi` file instead:
     33import os
     35os.environ['PYTHON_EGG_CACHE'] = '/usr/local/trac/mysite/eggs'
     37import trac.web.main
     38def application(environ, start_response):
     39  environ['trac.env_path'] = '/usr/local/trac/mysite'
     40  return trac.web.main.dispatch_request(environ, start_response)
     43For clarity, you should give this file a `.wsgi` extension. You should probably put the file in its own directory, since you will expose it to Apache.
     45If you have installed Trac and eggs in a path different from the standard one you should add that path by adding the following code at the top of the wsgi script:
     48import site
     52Change it according to the path you installed the Trac libs at.
     54=== Recommended `trac.wsgi` script
     56A somewhat robust and generic version of this file can be created using the `trac-admin <env> deploy <dir>` command which automatically substitutes the required paths (see TracInstall#cgi-bin).
     59== Mapping requests to the script
     61After you've done preparing your .wsgi script, add the following to your Apache configuration file (`httpd.conf` for example).
     64WSGIScriptAlias /trac /usr/local/trac/mysite/apache/mysite.wsgi
     66<Directory /usr/local/trac/mysite/apache>
     67    WSGIApplicationGroup %{GLOBAL}
     68    Order deny,allow
     69    Allow from all
     73Here, the script is in a subdirectory of the Trac environment.
     75If you followed the directions [ Generating the Trac cgi-bin directory], your Apache configuration file should look like following:
     78WSGIScriptAlias /trac /usr/share/trac/cgi-bin/trac.wsgi
     80<Directory /usr/share/trac/cgi-bin>
     81    WSGIApplicationGroup %{GLOBAL}
     82    Order deny,allow
     83    Allow from all
     87In order to let Apache run the script, access to the directory in which the script resides is opened up to all of Apache. Additionally, the `WSGIApplicationGroup` directive ensures that Trac is always run in the first Python interpreter created by mod_wsgi; this is necessary because the Subversion Python bindings, which are used by Trac, don't always work in other sub-interpreters and may cause requests to hang or cause Apache to crash as a result. After adding this configuration, restart Apache, and then it should work.
     89To test the setup of Apache, mod_wsgi and Python itself (ie. without involving Trac and dependencies), this simple wsgi application can be used to make sure that requests gets served (use as only content in your `.wsgi` script):
     92def application(environ, start_response):
     93        start_response('200 OK',[('Content-type','text/html')])
     94        return ['<html><body>Hello World!</body></html>']
     97For more information about using the mod_wsgi specific directives, see the [ mod_wsgi's wiki] and more specifically the [ IntegrationWithTrac] page.
     100== Configuring Authentication
     102We describe in the the following sections different methods for setting up authentication.
     104See also [ Authentication, Authorization and Access Control] in the Apache guide.
     106=== Using Basic Authentication ===
     108The simplest way to enable authentication with Apache is to create a password file. Use the `htpasswd` program to create the password file:
     110$ htpasswd -c /somewhere/trac.htpasswd admin
     111New password: <type password>
     112Re-type new password: <type password again>
     113Adding password for user admin
     116After the first user, you dont need the "-c" option anymore:
     118$ htpasswd /somewhere/trac.htpasswd john
     119New password: <type password>
     120Re-type new password: <type password again>
     121Adding password for user john
     124  ''See the man page for `htpasswd` for full documentation.''
     126After you've created the users, you can set their permissions using TracPermissions.
     128Now, you'll need to enable authentication against the password file in the Apache configuration:
     130<Location "/trac/login">
     131  AuthType Basic
     132  AuthName "Trac"
     133  AuthUserFile /somewhere/trac.htpasswd
     134  Require valid-user
     138If you're hosting multiple projects you can use the same password file for all of them:
     140<LocationMatch "/trac/[^/]+/login">
     141  AuthType Basic
     142  AuthName "Trac"
     143  AuthUserFile /somewhere/trac.htpasswd
     144  Require valid-user
     147Note that neither a file nor a directory named 'login' needs to exist.[[BR]]
     148See also the [ mod_auth_basic] documentation.
     150=== Using Digest Authentication ===
     152For better security, it is recommended that you either enable SSL or at least use the “digest” authentication scheme instead of “Basic”.
     154You'll have to create your `.htpasswd` file with the `htdigest` command instead of `htpasswd`, as follows:
     156# htdigest -c /somewhere/trac.htpasswd trac admin
     159The "trac" parameter above is the "realm", and will have to be reused in the Apache configuration in the !AuthName directive:
     162<Location "/trac/login">
     164    AuthType Digest
     165    AuthName "trac"
     166    AuthDigestDomain /trac
     167    AuthUserFile /somewhere/trac.htpasswd
     168    Require valid-user
     172For multiple environments, you can use the same `LocationMatch` as described with the previous method.
     174Don't forget to activate the mod_auth_digest. For example, on a Debian 4.0r1 (etch) system:
     176    LoadModule auth_digest_module /usr/lib/apache2/modules/
     180See also the [ mod_auth_digest] documentation.
     182=== Using LDAP Authentication
     184Configuration for [ mod_ldap] authentication in Apache is a bit tricky (httpd 2.2.x and OpenLDAP: slapd 2.3.19)
     1861. You need to load the following modules in Apache httpd.conf
     188LoadModule ldap_module modules/
     189LoadModule authnz_ldap_module modules/
     1922. Your httpd.conf also needs to look something like:
     195<Location /trac/>
     196  # (if you're using it, mod_python specific settings go here)
     197  Order deny,allow
     198  Deny from all
     199  Allow from
     200  AuthType Basic
     201  AuthName "Trac"
     202  AuthBasicProvider "ldap"
     203  AuthLDAPURL "ldap://,dc=co,dc=ke?uid?sub?(objectClass=inetOrgPerson)"
     204  authzldapauthoritative Off
     205  Require valid-user
     2103. You can use the LDAP interface as a way to authenticate to a Microsoft Active Directory:
     213Use the following as your LDAP URL:
     215    AuthLDAPURL "ldap://,DC=com?sAMAccountName?sub?(objectClass=user)"
     218You will also need to provide an account for Apache to use when checking
     219credentials. As this password will be listed in plaintext in the
     220config, you should be sure to use an account specifically for this task:
     222    AuthLDAPBindDN
     223    AuthLDAPBindPassword "password"
     226The whole section looks like:
     228<Location /trac/>
     229  # (if you're using it, mod_python specific settings go here)
     230  Order deny,allow
     231  Deny from all
     232  Allow from
     233  AuthType Basic
     234  AuthName "Trac"
     235  AuthBasicProvider "ldap"
     236  AuthLDAPURL "ldap://,DC=com?sAMAccountName?sub?(objectClass=user)"
     237  AuthLDAPBindDN
     238  AuthLDAPBindPassword "the_password"
     239  authzldapauthoritative Off
     240  # require valid-user
     241  require ldap-group CN=Trac Users,CN=Users,DC=company,DC=com
     245Note 1: This is the case where the LDAP search will get around the multiple OUs, conecting to Global Catalog Server portion of AD (Notice the port is 3268, not the normal LDAP 389). The GCS is basically a "flattened" tree which allows searching for a user without knowing to which OU they belong.
     247Note 2: You can also require the user be a member of a certain LDAP group, instead of
     248just having a valid login:
     250    Require ldap-group CN=Trac Users,CN=Users,DC=example,DC=com
     253See also:
     254  - [ mod_authnz_ldap], documentation for mod_authnz_ldap
     256 - [ mod_ldap], documentation for mod_ldap, which provides connection pooling and a shared cache.
     257 - [ TracHacks:LdapPlugin] for storing TracPermissions in LDAP.
     259=== Using SSPI Authentication
     261If you are using Apache on Windows, you can use mod_auth_sspi to provide
     262single-sign-on. Download the module from the !SourceForge [ mod-auth-sspi project] and then add the
     263following to your !VirtualHost:
     265    <Location /trac/login>
     266        AuthType SSPI
     267        AuthName "Trac Login"
     268        SSPIAuth On
     269        SSPIAuthoritative On
     270        SSPIDomain MyLocalDomain
     271        SSPIOfferBasic On
     272        SSPIOmitDomain Off
     273        SSPIBasicPreferred On
     274        Require valid-user
     275    </Location>
     278Using the above, usernames in Trac will be of the form `DOMAIN\username`, so
     279you may have to re-add permissions and such. If you do not want the domain to
     280be part of the username, set `SSPIOmitDomain On` instead.
     282Some common problems with SSPI authentication: [trac:#1055], [trac:#1168] and [trac:#3338].
     284See also [trac:TracOnWindows/Advanced].
     286=== Using Apache authentication with the Account Manager plugin's Login form ===
     288To begin with, see the basic instructions for using the Account Manager plugin's [ Login module] and its [ HttpAuthStore authentication module].
     290'''Note:''' If is difficult to get !HttpAuthStore to work with WSGI when using any Account Manager version prior to acct_mgr-0.4. Upgrading is recommended.
     292Here is an example (from the !HttpAuthStore link) using acct_mgr-0.4 for hosting a single project:
     295; be sure to enable the component
     296acct_mgr.http.HttpAuthStore = enabled
     299; configure the plugin to use a page that is secured with http authentication
     300authentication_url = /authFile
     301password_store = HttpAuthStore
     303This will generally be matched with an Apache config like:
     305<Location /authFile>
     306   …HTTP authentication configuration…
     307   Require valid-user
     310Note that '''authFile''' need not exist. See the !HttpAuthStore link above for examples where multiple Trac projects are hosted on a server.
     312=== Example: Apache/mod_wsgi with Basic Authentication, Trac being at the root of a virtual host
     314Per the mod_wsgi documentation linked to above, here is an example Apache configuration that a) serves the Trac instance from a virtualhost subdomain and b) uses Apache basic authentication for Trac authentication.
     317If you want your Trac to be served from e.g. !, then from the folder e.g. `/home/trac-for-my-proj`, if you used the command `trac-admin the-env initenv` to create a folder `the-env`, and you used `trac-admin the-env deploy the-deploy` to create a folder `the-deploy`, then first:
     319Create the htpasswd file:
     321cd /home/trac-for-my-proj/the-env
     322htpasswd -c htpasswd firstuser
     323### and add more users to it as needed:
     324htpasswd htpasswd seconduser
     326(keep the file above your document root for security reasons)
     328Create this file e.g. (ubuntu) `/etc/apache2/sites-enabled/` with the following contents:
     331<Directory /home/trac-for-my-proj/the-deploy/cgi-bin/trac.wsgi>
     332  WSGIApplicationGroup %{GLOBAL}
     333  Order deny,allow
     334  Allow from all
     337<VirtualHost *:80>
     338  ServerName
     339  DocumentRoot /home/trac-for-my-proj/the-env/htdocs/
     340  WSGIScriptAlias / /home/trac-for-my-proj/the-deploy/cgi-bin/trac.wsgi
     341  <Location '/'>
     342    AuthType Basic
     343    AuthName "Trac"
     344    AuthUserFile /home/trac-for-my-proj/the-env/htpasswd
     345    Require valid-user
     346  </Location>
     351Note: for subdomains to work you would probably also need to alter `/etc/hosts` and add A-Records to your host's DNS.
     354== Troubleshooting
     356=== Use a recent version
     358Please use either version 1.6, 2.4 or later of `mod_wsgi`. Versions prior to 2.4 in the 2.X branch have problems with some Apache configurations that use WSGI file wrapper extension. This extension is used in Trac to serve up attachments and static media files such as style sheets. If you are affected by this problem attachments will appear to be empty and formatting of HTML pages will appear not to work due to style sheet files not loading properly. Another frequent symptom is that binary attachment downloads are truncated. See mod_wsgi tickets [ #100] and [ #132].
     360''Note: using mod_wsgi 2.5 and Python 2.6.1 gave an Internal Server Error on my system (Apache 2.2.11 and Trac Upgrading to Python 2.6.2 (as suggested [ here]) solved this for me[[BR]]-- Graham Shanks''
     362If you plan to use `mod_wsgi` in embedded mode on Windows or with the MPM worker on Linux, then you'll even need version 0.3.4 or greater (see [trac:#10675] for details).
     364=== Getting Trac to work nicely with SSPI and 'Require Group' ===
     365If like me you've set Trac up on Apache, Win32 and configured SSPI, but added a 'Require group' option to your apache configuration, then the SSPIOmitDomain option is probably not working.  If its not working your usernames in trac are probably looking like 'DOMAIN\user' rather than 'user'.
     367This WSGI script 'fixes' things, hope it helps:
     369import os
     370import trac.web.main
     372os.environ['TRAC_ENV'] = '/usr/local/trac/mysite'
     373os.environ['PYTHON_EGG_CACHE'] = '/usr/local/trac/mysite/eggs'
     375def application(environ, start_response):
     376    if "\\" in environ['REMOTE_USER']:
     377        environ['REMOTE_USER'] = environ['REMOTE_USER'].split("\\", 1)[1]
     378    return trac.web.main.dispatch_request(environ, start_response)
     382=== Trac with PostgreSQL ===
     384When using the mod_wsgi adapter with multiple Trac instances and PostgreSQL (or MySQL?) as a database back-end, the server ''may'' create a lot of open database connections and thus PostgreSQL processes.
     386A somewhat brutal workaround is to disabled connection pooling in Trac. This is done by setting `poolable = False` in `trac.db.postgres_backend` on the `PostgreSQLConnection` class.
     388But it's not necessary to edit the source of Trac, the following lines in `trac.wsgi` will also work:
     391import trac.db.postgres_backend
     392trac.db.postgres_backend.PostgreSQLConnection.poolable = False
     398import trac.db.mysql_backend
     399trac.db.mysql_backend.MySQLConnection.poolable = False
     402Now Trac drops the connection after serving a page and the connection count on the database will be kept minimal.
     404//This is not a recommended approach though. See also the notes at the bottom of the [ mod_wsgi's IntegrationWithTrac] wiki page.//
     406=== Other resources
     408For more troubleshooting tips, see also the [TracModPython#Troubleshooting mod_python troubleshooting] section, as most Apache-related issues are quite similar, plus discussion of potential [ application issues] when using mod_wsgi. The wsgi page also has a [ Integration With Trac] document.
     412See also:  TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]