Changes between Initial Version and Version 1 of TracModWSGI

08/07/15 22:11:27 (5 years ago)



  • TracModWSGI

    v1 v1  
     1= Trac and mod_wsgi =
     3[ 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 performance.
     7== The `trac.wsgi` script
     9Trac 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.
     11=== A very basic script
     12In its simplest form, the script could be:
     15import os
     17os.environ['TRAC_ENV'] = '/usr/local/trac/mysite'
     18os.environ['PYTHON_EGG_CACHE'] = '/usr/local/trac/mysite/eggs'
     20import trac.web.main
     21application = trac.web.main.dispatch_request
     24The `TRAC_ENV` variable should naturally be the directory for your Trac environment, and the `PYTHON_EGG_CACHE` should be a directory where Python can temporarily extract Python eggs. If you have several Trac environments in a directory, you can also use `TRAC_ENV_PARENT_DIR` instead of `TRAC_ENV`.
     26On Windows:
     27 - If run under the user's session, the Python Egg cache can be found in `%AppData%\Roaming`, for example:
     29os.environ['PYTHON_EGG_CACHE'] = r'C:\Users\Administrator\AppData\Roaming\Python-Eggs'
     31 - If run under a Window service, you should create a directory for Python Egg cache:
     33os.environ['PYTHON_EGG_CACHE'] = r'C:\Trac-Python-Eggs'
     36=== A more elaborate script
     38If you are 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.
     40To solve this problem, use the following `.wsgi` file instead:
     42import os
     44os.environ['PYTHON_EGG_CACHE'] = '/usr/local/trac/mysite/eggs'
     46import trac.web.main
     47def application(environ, start_response):
     48  environ['trac.env_path'] = '/usr/local/trac/mysite'
     49  return trac.web.main.dispatch_request(environ, start_response)
     52For 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.
     54If you have installed Trac and Python 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:
     57import site
     61Change it according to the path you installed the Trac libs at.
     63=== Recommended `trac.wsgi` script
     65A 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.
     67If you are using Trac with multiple projects, you can specify their common parent directory using the `TRAC_ENV_PARENT_DIR` in the trac.wsgi in trac.wsgi: ''
     70  def application(environ, start_request):
     71      Add this to config when you have multiple projects                                             
     72      environ.setdefault('trac.env_parent_dir', '/usr/share/trac/projects') 
     73      ..
     74      ..
     77== Mapping requests to the script
     79After preparing your .wsgi script, add the following to your Apache configuration file, typically `httpd.conf`:
     82WSGIScriptAlias /trac /usr/local/trac/mysite/apache/mysite.wsgi
     84<Directory /usr/local/trac/mysite/apache>
     85    WSGIApplicationGroup %{GLOBAL}
     86    Order deny,allow
     87    Allow from all
     91Here, the script is in a subdirectory of the Trac environment.
     93If you followed the directions [TracInstall#cgi-bin Generating the Trac cgi-bin directory], your Apache configuration file should look like following:
     96WSGIScriptAlias /trac /usr/share/trac/cgi-bin/trac.wsgi
     98<Directory /usr/share/trac/cgi-bin>
     99    WSGIApplicationGroup %{GLOBAL}
     100    Order deny,allow
     101    Allow from all
     105In 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. After adding this configuration, restart Apache, and then it should work.
     107To 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):
     110def application(environ, start_response):
     111        start_response('200 OK',[('Content-type','text/html')])
     112        return ['<html><body>Hello World!</body></html>']
     115For more information about using the mod_wsgi specific directives, see the [ mod_wsgi's wiki] and more specifically the [ IntegrationWithTrac] page.
     117== Configuring Authentication
     119The following sections describe different methods for setting up authentication. See also [ Authentication, Authorization and Access Control] in the Apache guide.
     121=== Using Basic Authentication ===
     123The simplest way to enable authentication with Apache is to create a password file. Use the `htpasswd` program as follows:
     125$ htpasswd -c /somewhere/trac.htpasswd admin
     126New password: <type password>
     127Re-type new password: <type password again>
     128Adding password for user admin
     131After the first user, you don't need the "-c" option anymore:
     133$ htpasswd /somewhere/trac.htpasswd john
     134New password: <type password>
     135Re-type new password: <type password again>
     136Adding password for user john
     139  ''See the man page for `htpasswd` for full documentation.''
     141After you've created the users, you can set their permissions using TracPermissions.
     143Now, you need to enable authentication against the password file in the Apache configuration:
     145<Location "/trac/login">
     146  AuthType Basic
     147  AuthName "Trac"
     148  AuthUserFile /somewhere/trac.htpasswd
     149  Require valid-user
     153If you are hosting multiple projects, you can use the same password file for all of them:
     155<LocationMatch "/trac/[^/]+/login">
     156  AuthType Basic
     157  AuthName "Trac"
     158  AuthUserFile /somewhere/trac.htpasswd
     159  Require valid-user
     162Note that neither a file nor a directory named 'login' needs to exist.[[BR]]
     163See also the [ mod_auth_basic] documentation.
     165=== Using Digest Authentication ===
     167For better security, it is recommended that you either enable SSL or at least use the “digest” authentication scheme instead of “Basic”.
     169You have to create your `.htpasswd` file with the `htdigest` command instead of `htpasswd`, as follows:
     171# htdigest -c /somewhere/trac.htpasswd trac admin
     174The "trac" parameter above is the "realm", and will have to be reused in the Apache configuration in the !AuthName directive:
     177<Location "/trac/login">
     179    AuthType Digest
     180    AuthName "trac"
     181    AuthDigestDomain /trac
     182    AuthUserFile /somewhere/trac.htpasswd
     183    Require valid-user
     187For multiple environments, you can use the same `LocationMatch` as described with the previous method.
     189'''Note: `Location` cannot be used inside .htaccess files, but must instead live within the main httpd.conf file. If you are on a shared server, you therefore will not be able to provide this level of granularity. '''
     191Don't forget to activate the mod_auth_digest. For example, on a Debian 4.0r1 (etch) system:
     193    LoadModule auth_digest_module /usr/lib/apache2/modules/
     196See also the [ mod_auth_digest] documentation.
     198=== Using LDAP Authentication
     200Configuration for [ mod_ldap] authentication in Apache is more involved (httpd 2.2.x and OpenLDAP: slapd 2.3.19).
     2021. You need to load the following modules in Apache httpd.conf:
     204LoadModule ldap_module modules/
     205LoadModule authnz_ldap_module modules/
     2082. Your httpd.conf also needs to look something like:
     211<Location /trac/>
     212  # (if you're using it, mod_python specific settings go here)
     213  Order deny,allow
     214  Deny from all
     215  Allow from
     216  AuthType Basic
     217  AuthName "Trac"
     218  AuthBasicProvider "ldap"
     219  AuthLDAPURL "ldap://,dc=co,dc=ke?uid?sub?(objectClass=inetOrgPerson)"
     220  authzldapauthoritative Off
     221  Require valid-user
     2253. You can use the LDAP interface as a way to authenticate to a Microsoft Active Directory:
     227Use the following as your LDAP URL:
     229    AuthLDAPURL "ldap://,DC=com?sAMAccountName?sub?(objectClass=user)"
     232You will also need to provide an account for Apache to use when checking credentials. As this password will be listed in plaintext in the config, you need to use an account specifically for this task:
     234    AuthLDAPBindDN
     235    AuthLDAPBindPassword "password"
     238The whole section looks like:
     240<Location /trac/>
     241  # (if you're using it, mod_python specific settings go here)
     242  Order deny,allow
     243  Deny from all
     244  Allow from
     245  AuthType Basic
     246  AuthName "Trac"
     247  AuthBasicProvider "ldap"
     248  AuthLDAPURL "ldap://,DC=com?sAMAccountName?sub?(objectClass=user)"
     249  AuthLDAPBindDN
     250  AuthLDAPBindPassword "the_password"
     251  authzldapauthoritative Off
     252  # require valid-user
     253  require ldap-group CN=Trac Users,CN=Users,DC=company,DC=com
     257Note 1: This is the case where the LDAP search will get around the multiple OUs, conecting to the Global Catalog Server portion of AD. Note 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.
     259Note 2: You can also require the user be a member of a certain LDAP group, instead of just having a valid login:
     261    Require ldap-group CN=Trac Users,CN=Users,DC=example,DC=com
     264See also:
     265 - [ mod_authnz_ldap], documentation for mod_authnz_ldap.   
     266 - [ mod_ldap], documentation for mod_ldap, which provides connection pooling and a shared cache.
     267 - [ TracHacks:LdapPlugin] for storing TracPermissions in LDAP.
     269=== Using SSPI Authentication
     271If you are using Apache on Windows, you can use mod_auth_sspi to provide single-sign-on. Download the module from the !SourceForge [ mod-auth-sspi project] and then add the following to your !VirtualHost:
     273    <Location /trac/login>
     274        AuthType SSPI
     275        AuthName "Trac Login"
     276        SSPIAuth On
     277        SSPIAuthoritative On
     278        SSPIDomain MyLocalDomain
     279        SSPIOfferBasic On
     280        SSPIOmitDomain Off
     281        SSPIBasicPreferred On
     282        Require valid-user
     283    </Location>
     286Using the above, usernames in Trac will be of the form `DOMAIN\username`, so you may have to re-add permissions and such. If you do not want the domain to be part of the username, set `SSPIOmitDomain On` instead.
     288Some common problems with SSPI authentication: [trac:#1055], [trac:#1168] and [trac:#3338].
     290See also [trac:TracOnWindows/Advanced].
     292=== Using Apache authentication with the Account Manager plugin's Login form ===
     294To begin with, see the basic instructions for using the Account Manager plugin's [ Login module] and its [ HttpAuthStore authentication module].
     296'''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.
     298Here is an example (from the !HttpAuthStore link) using acct_mgr-0.4 for hosting a single project:
     301; be sure to enable the component
     302acct_mgr.http.HttpAuthStore = enabled
     305; configure the plugin to use a page that is secured with http authentication
     306authentication_url = /authFile
     307password_store = HttpAuthStore
     309This will generally be matched with an Apache config like:
     311<Location /authFile>
     312   …HTTP authentication configuration…
     313   Require valid-user
     316Note that '''authFile''' need not exist (unless you are using Account Manager older than 0.4). See the !HttpAuthStore link above for examples where multiple Trac projects are hosted on a server.
     318=== Example: Apache/mod_wsgi with Basic Authentication, Trac being at the root of a virtual host
     320Per the mod_wsgi documentation linked to above, here is an example Apache configuration that:
     321 - serves the Trac instance from a virtualhost subdomain
     322 - uses Apache basic authentication for Trac authentication.
     324If 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:
     326Create the htpasswd file:
     328cd /home/trac-for-my-proj/the-env
     329htpasswd -c htpasswd firstuser
     330### and add more users to it as needed:
     331htpasswd htpasswd seconduser
     333Keep the file above your document root for security reasons.
     335Create this file e.g. (ubuntu) `/etc/apache2/sites-enabled/` with the following content:
     338<Directory /home/trac-for-my-proj/the-deploy/cgi-bin/trac.wsgi>
     339  WSGIApplicationGroup %{GLOBAL}
     340  Order deny,allow
     341  Allow from all
     344<VirtualHost *:80>
     345  ServerName
     346  DocumentRoot /home/trac-for-my-proj/the-env/htdocs/
     347  WSGIScriptAlias / /home/trac-for-my-proj/the-deploy/cgi-bin/trac.wsgi
     348  <Location '/'>
     349    AuthType Basic
     350    AuthName "Trac"
     351    AuthUserFile /home/trac-for-my-proj/the-env/htpasswd
     352    Require valid-user
     353  </Location>
     358Note: for subdomains to work you would probably also need to alter `/etc/hosts` and add A-Records to your host's DNS.
     360== Troubleshooting
     362=== Use a recent version
     364Please 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].
     366''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''
     368If you plan to use `mod_wsgi` in embedded mode on Windows or with the MPM worker on Linux, then you will need version 0.3.4 or greater. See [trac:#10675] for details.
     370=== Getting Trac to work nicely with SSPI and 'Require Group' ===
     372If you have 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 it is not working, your usernames in Trac probably look like 'DOMAIN\user' rather than 'user'.
     374This WSGI script 'fixes' that:
     376import os
     377import trac.web.main
     379os.environ['TRAC_ENV'] = '/usr/local/trac/mysite'
     380os.environ['PYTHON_EGG_CACHE'] = '/usr/local/trac/mysite/eggs'
     382def application(environ, start_response):
     383    if "\\" in environ['REMOTE_USER']:
     384        environ['REMOTE_USER'] = environ['REMOTE_USER'].split("\\", 1)[1]
     385    return trac.web.main.dispatch_request(environ, start_response)
     388=== Trac with PostgreSQL ===
     390When using the mod_wsgi adapter with multiple Trac instances and PostgreSQL (or MySQL?) as the database, the server ''may'' create a lot of open database connections and thus PostgreSQL processes.
     392A somewhat brutal workaround is to disable connection pooling in Trac. This is done by setting `poolable = False` in `trac.db.postgres_backend` on the `PostgreSQLConnection` class.
     394But it is not necessary to edit the source of Trac. The following lines in `trac.wsgi` will also work:
     397import trac.db.postgres_backend
     398trac.db.postgres_backend.PostgreSQLConnection.poolable = False
     404import trac.db.mysql_backend
     405trac.db.mysql_backend.MySQLConnection.poolable = False
     408Now Trac drops the connection after serving a page and the connection count on the database will be kept low.
     410//This is not a recommended approach though. See also the notes at the bottom of the [ mod_wsgi's IntegrationWithTrac] wiki page.//
     412=== Other resources
     414For 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.
     417See also: TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]