Changes between Version 3 and Version 4 of TracModWSGI


Ignore:
Timestamp:
01/09/21 11:52:22 (11 months ago)
Author:
trac
Comment:

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  • TracModWSGI

    v3 v4  
    1 = Trac and mod_wsgi =
    2 
    3 '''Important note:''' ''Please 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. See mod_wsgi tickets [http://code.google.com/p/modwsgi/issues/detail?id=100 #100] and [http://code.google.com/p/modwsgi/issues/detail?id=132 #132].''
    4 
    5 [http://code.google.com/p/modwsgi/ mod_wsgi] is an Apache module for running WSGI-compatible Python applications directly on top of Apache. The mod_wsgi adapter is written completely in C and provides significantly better performance than using existing WSGI adapters for mod_python or CGI.
    6 
    7 Trac 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). This file can be created using '''trac-admin <env> deploy <dir>''' command which automatically substitutes required paths.
    8 
    9 {{{
    10 #!python
     1= Trac and mod_wsgi
     2
     3[https://github.com/GrahamDumpleton/mod_wsgi 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.
     4
     5[[PageOutline(2-3,Overview,inline)]]
     6
     7== The `trac.wsgi` script
     8
     9Trac can be run on top of mod_wsgi with the help of an application script, which is a Python file saved with a `.wsgi` extension.
     10
     11A 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. The script should be sufficient for most installations and users not wanting more information can proceed to [#Mappingrequeststothescript configuring Apache].
     12
     13If you are using Trac with multiple projects, you can specify their common parent directory in `trac.wsgi`:
     14{{{#!python
     15def application(environ, start_request):
     16    # Add this when you have multiple projects
     17    environ.setdefault('trac.env_parent_dir', '/usr/share/trac/projects')
     18    ..
     19}}}
     20
     21Directories residing in `trac.env_parent_dir` that are not environment directories will display an error message on the [TracInterfaceCustomization#ProjectList project index page]. The directories can be excluded by listing them in a `.tracignore` file residing in `trac.env_parent_dir`. Unix [https://docs.python.org/2/library/fnmatch.html shell-style wildcard patterns] can be used in the newline separated list of directories.
     22
     23=== A very basic script
     24
     25In its simplest form, the script could be:
     26
     27{{{#!python
    1128import os
    1229
     
    1835}}}
    1936
    20 The `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.
    21 
    22 '''Important note:''' If 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. (The variable may be filled with the path of a previously viewed Trac environment.) To solve this problem, use the following `.wsgi` file instead:
    23 
    24 {{{
    25 #!python
     37The `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`.
     38
     39On Windows:
     40 - If run under the user's session, the Python Egg cache can be found in `%AppData%\Roaming`, for example:
     41{{{#!python
     42os.environ['PYTHON_EGG_CACHE'] = r'C:\Users\Administrator\AppData\Roaming\Python-Eggs'
     43}}}
     44 - If run under a Window service, you should create a directory for Python Egg cache:
     45{{{#!python
     46os.environ['PYTHON_EGG_CACHE'] = r'C:\Trac-Python-Eggs'
     47}}}
     48
     49=== A more elaborate script
     50
     51If 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.
     52
     53To solve this problem, use the following `.wsgi` file instead:
     54{{{#!python
    2655import os
    2756
     
    3059import trac.web.main
    3160def application(environ, start_response):
    32   environ['trac.env_path'] = '/usr/local/trac/mysite' 
     61  environ['trac.env_path'] = '/usr/local/trac/mysite'
    3362  return trac.web.main.dispatch_request(environ, start_response)
    3463}}}
    3564
    36 For clarity, you should give this file a `.wsgi` extension. You should probably put the file in it's own directory, since you will open up its directory to Apache. You can create a .wsgi files which handles all this for you by running the TracAdmin command `deploy`.
    37 
    38 If you have installed trac and eggs in a path different from the standard one you should add that path by adding the following code on top of the wsgi script:
    39 
    40 {{{
    41 #!python
     65For 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.
     66
     67If 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:
     68
     69{{{#!python
    4270import site
    4371site.addsitedir('/usr/local/trac/lib/python2.4/site-packages')
    4472}}}
    4573
    46 Change it according to the path you installed the trac libs at.
    47 
    48 After you've done preparing your wsgi-script, add the following to your httpd.conf.
    49 
    50 {{{
     74Change it according to the path you installed the Trac libs at.
     75
     76== Mapping requests to the script
     77
     78After preparing your .wsgi script, add the following to your Apache configuration file, typically `httpd.conf`:
     79
     80{{{#!apache
    5181WSGIScriptAlias /trac /usr/local/trac/mysite/apache/mysite.wsgi
    5282
    5383<Directory /usr/local/trac/mysite/apache>
    5484    WSGIApplicationGroup %{GLOBAL}
    55     Order deny,allow
    56     Allow from all
     85    # For Apache 2.2
     86    <IfModule !mod_authz_core.c>
     87        Order deny,allow
     88        Allow from all
     89    </IfModule>
     90    # For Apache 2.4
     91    <IfModule mod_authz_core.c>
     92        Require all granted
     93    </IfModule>
    5794</Directory>
    5895}}}
    5996
    60 Here, the script is in a subdirectory of the Trac environment. In 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 subinterpreters 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.
    61 
    62 To 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):
    63 
    64 {{{
     97Here, the script is in a subdirectory of the Trac environment.
     98
     99If you followed the directions [TracInstall#cgi-bin Generating the Trac cgi-bin directory], your Apache configuration file should look like following:
     100
     101{{{#!apache
     102WSGIScriptAlias /trac /usr/share/trac/cgi-bin/trac.wsgi
     103
     104<Directory /usr/share/trac/cgi-bin>
     105    WSGIApplicationGroup %{GLOBAL}
     106    # For Apache 2.2
     107    <IfModule !mod_authz_core.c>
     108        Order deny,allow
     109        Allow from all
     110    </IfModule>
     111    # For Apache 2.4
     112    <IfModule mod_authz_core.c>
     113        Require all granted
     114    </IfModule>
     115</Directory>
     116}}}
     117
     118In 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.
     119
     120To 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):
     121
     122{{{#!python
    65123def application(environ, start_response):
    66124        start_response('200 OK',[('Content-type','text/html')])
     
    68126}}}
    69127
    70 See also the mod_wsgi [http://code.google.com/p/modwsgi/wiki/IntegrationWithTrac installation instructions] for Trac.
    71 
    72 For troubleshooting tips, see the [TracModPython#Troubleshooting mod_python troubleshooting] section, as most Apache-related issues are quite similar, plus discussion of potential [http://code.google.com/p/modwsgi/wiki/ApplicationIssues application issues] when using mod_wsgi.
    73 
    74 ''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 0.11.2.1). Upgrading to Python 2.6.2 (as suggested [http://www.mail-archive.com/modwsgi@googlegroups.com/msg01917.html here]) solved this for me[[BR]]-- Graham Shanks''
    75 
    76 == Apache Basic Authentication for Trac thru mod_wsgi ==
    77 
    78 Per the mod_wsgi documentation linked to above, here is an example Apache configuration that a) serves the trac from a virtualhost subdomain and b) uses Apache basic authentication for Trac authentication.
    79 
    80 
    81 If you want your trac to be served from e.g. !http://trac.my-proj.my-site.org, 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:
    82 
    83 create the htpasswd file:
    84 {{{
     128For more information about using the mod_wsgi specific directives, see the [https://code.google.com/archive/p/modwsgi/wikis mod_wsgi's wiki] and more specifically the [https://code.google.com/archive/p/modwsgi/wikis/IntegrationWithTrac.wiki IntegrationWithTrac] page.
     129
     130== Configuring Authentication
     131
     132The following sections describe different methods for setting up authentication. See also [https://httpd.apache.org/docs/2.4/howto/auth.html Authentication, Authorization and Access Control] in the Apache guide.
     133
     134=== Using Basic Authentication
     135
     136The simplest way to enable authentication with Apache is to create a password file. Use the `htpasswd` program as follows:
     137{{{#!sh
     138$ htpasswd -c /somewhere/trac.htpasswd admin
     139New password: <type password>
     140Re-type new password: <type password again>
     141Adding password for user admin
     142}}}
     143
     144After the first user, you don't need the "-c" option anymore:
     145{{{#!sh
     146$ htpasswd /somewhere/trac.htpasswd john
     147New password: <type password>
     148Re-type new password: <type password again>
     149Adding password for user john
     150}}}
     151
     152See the man page for `htpasswd` for full documentation.
     153
     154After you've created the users, you can set their permissions using TracPermissions.
     155
     156Now, you need to enable authentication against the password file in the Apache configuration:
     157{{{#!apache
     158<Location "/trac/login">
     159  AuthType Basic
     160  AuthName "Trac"
     161  AuthUserFile /somewhere/trac.htpasswd
     162  Require valid-user
     163</Location>
     164}}}
     165
     166If you are hosting multiple projects, you can use the same password file for all of them:
     167{{{#!apache
     168<LocationMatch "/trac/[^/]+/login">
     169  AuthType Basic
     170  AuthName "Trac"
     171  AuthUserFile /somewhere/trac.htpasswd
     172  Require valid-user
     173</LocationMatch>
     174}}}
     175
     176Note that neither a file nor a directory named 'login' needs to exist. See also the [https://httpd.apache.org/docs/2.4/mod/mod_auth_basic.html mod_auth_basic] documentation.
     177
     178=== Using Digest Authentication
     179
     180For better security, it is recommended that you either enable SSL or at least use the "digest" authentication scheme instead of "Basic".
     181
     182You have to create your `.htpasswd` file with the `htdigest` command instead of `htpasswd`, as follows:
     183{{{#!sh
     184$ htdigest -c /somewhere/trac.htpasswd trac admin
     185}}}
     186
     187The "trac" parameter above is the "realm", and will have to be reused in the Apache configuration in the !AuthName directive:
     188
     189{{{#!apache
     190<Location "/trac/login">
     191  AuthType Digest
     192  AuthName "trac"
     193  AuthDigestDomain /trac
     194  AuthUserFile /somewhere/trac.htpasswd
     195  Require valid-user
     196</Location>
     197}}}
     198
     199For multiple environments, you can use the same `LocationMatch` as described with the previous method.
     200
     201'''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.
     202
     203Don't forget to activate the mod_auth_digest. For example, on a Debian 4.0r1 (etch) system:
     204{{{#!apache
     205  LoadModule auth_digest_module /usr/lib/apache2/modules/mod_auth_digest.so
     206}}}
     207
     208See also the [https://httpd.apache.org/docs/2.4/mod/mod_auth_basic.html mod_auth_digest] documentation.
     209
     210=== Using LDAP Authentication
     211
     212Configuration for [https://httpd.apache.org/docs/2.4/mod/mod_ldap.html mod_ldap] authentication in Apache is more involved (httpd 2.2+ and OpenLDAP: slapd 2.3.19).
     213
     2141. You need to load the following modules in Apache httpd.conf:
     215{{{#!apache
     216  LoadModule ldap_module modules/mod_ldap.so
     217  LoadModule authnz_ldap_module modules/mod_authnz_ldap.so
     218}}}
     2191. Your httpd.conf also needs to look something like:
     220{{{#!apache
     221<Location /trac/>
     222  # (if you're using it, mod_python specific settings go here)
     223  Order deny,allow
     224  Deny from all
     225  Allow from 192.168.11.0/24
     226  AuthType Basic
     227  AuthName "Trac"
     228  AuthBasicProvider "ldap"
     229  AuthLDAPURL "ldap://127.0.0.1/dc=example,dc=co,dc=ke?uid?sub?(objectClass=inetOrgPerson)"
     230  authzldapauthoritative Off
     231  Require valid-user
     232</Location>
     233}}}
     2341. You can use the LDAP interface as a way to authenticate to a Microsoft Active Directory. Use the following as your LDAP URL:
     235{{{#!apache
     236  AuthLDAPURL "ldap://directory.example.com:3268/DC=example,DC=com?sAMAccountName?sub?(objectClass=user)"
     237}}}
     238 You will also need to provide an account for Apache to use when checking credentials. As this password will be listed in plain text in the configuration, you need to use an account specifically for this task:
     239{{{#!apache
     240  AuthLDAPBindDN ldap-auth-user@example.com
     241  AuthLDAPBindPassword "password"
     242}}}
     243 The whole section looks like:
     244{{{#!apache
     245<Location /trac/>
     246  # (if you're using it, mod_python specific settings go here)
     247  Order deny,allow
     248  Deny from all
     249  Allow from 192.168.11.0/24
     250  AuthType Basic
     251  AuthName "Trac"
     252  AuthBasicProvider "ldap"
     253  AuthLDAPURL "ldap://adserver.company.com:3268/DC=company,DC=com?sAMAccountName?sub?(objectClass=user)"
     254  AuthLDAPBindDN       ldap-auth-user@company.com
     255  AuthLDAPBindPassword "the_password"
     256  authzldapauthoritative Off
     257  # require valid-user
     258  Require ldap-group CN=Trac Users,CN=Users,DC=company,DC=com
     259</Location>
     260}}}
     261
     262Note 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.
     263
     264Note 2: You can also require the user be a member of a certain LDAP group, instead of just having a valid login:
     265{{{#!apache
     266  Require ldap-group CN=Trac Users,CN=Users,DC=example,DC=com
     267}}}
     268
     269See also:
     270 - [https://httpd.apache.org/docs/2.4/mod/mod_authnz_ldap.html mod_authnz_ldap], documentation for mod_authnz_ldap.
     271 - [https://httpd.apache.org/docs/2.4/mod/mod_ldap.html mod_ldap], documentation for mod_ldap, which provides connection pooling and a shared cache.
     272 - [https://trac-hacks.org/wiki/LdapPlugin TracHacks:LdapPlugin] for storing TracPermissions in LDAP.
     273
     274=== Using SSPI Authentication
     275
     276If you are using Apache on Windows, you can use mod_auth_sspi to provide single-sign-on. Download the module from the !SourceForge [https://sourceforge.net/projects/mod-auth-sspi/ mod-auth-sspi project] and then add the following to your !VirtualHost:
     277{{{#!apache
     278<Location /trac/login>
     279  AuthType SSPI
     280  AuthName "Trac Login"
     281  SSPIAuth On
     282  SSPIAuthoritative On
     283  SSPIDomain MyLocalDomain
     284  SSPIOfferBasic On
     285  SSPIOmitDomain Off
     286  SSPIBasicPreferred On
     287  Require valid-user
     288</Location>
     289}}}
     290
     291Using 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.
     292
     293Some common problems with SSPI authentication: [trac:#1055], [trac:#1168] and [trac:#3338].
     294
     295See also [trac:TracOnWindows/Advanced].
     296
     297=== Using CA !SiteMinder Authentication
     298
     299Setup CA !SiteMinder to protect your Trac login URL, for example `/trac/login`. Also, make sure the policy is set to include the HTTP_REMOTE_USER variable. If your site allows it, you can set this in `LocalConfig.conf`:
     300{{{#!apache
     301RemoteUserVar="WHATEVER_IT_SHOULD_BE"
     302SetRemoteUser="YES"
     303}}}
     304
     305The specific variable is site-dependent. Ask your site administrator. If your site does not allow the use of `LocalConfig.conf` for security reasons, have your site administrator set the policy on the server to set REMOTE_USER.
     306
     307Also add a !LogOffUri parameter to the agent configuration, for example `/trac/logout`.
     308
     309Then modify the trac.wsgi script generated using `trac-admin <env> deploy <dir>` to add the following lines, which extract the `HTTP_REMOTE_USER` variable and set it to `REMOTE_USER`:
     310
     311{{{#!python
     312def application(environ, start_request):
     313    # Set authenticated username on CA SiteMinder to REMOTE_USER variable
     314    # strip() is used to remove any spaces on the end of the string
     315    if 'HTTP_SM_USER' in environ:
     316        environ['REMOTE_USER'] = environ['HTTP_REMOTE_USER'].strip()
     317    ...
     318}}}
     319
     320You do not need any Apache "Location" directives.
     321
     322=== Example: Apache/mod_wsgi with Basic Authentication, Trac being at the root of a virtual host
     323
     324Per the mod_wsgi documentation linked to above, here is an example Apache configuration that:
     325 - serves the Trac instance from a virtualhost subdomain
     326 - uses Apache basic authentication for Trac authentication.
     327
     328If you want your Trac to be served from eg !http://trac.my-proj.my-site.org, then from the folder eg `/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:
     329
     330Create the htpasswd file:
     331{{{#!sh
    85332cd /home/trac-for-my-proj/the-env
    86333htpasswd -c htpasswd firstuser
     
    88335htpasswd htpasswd seconduser
    89336}}}
    90 (for security keep the file above your document root)
    91 
    92 create this file e.g. (ubuntu) {{{/etc/apache2/sites-enabled/trac.my-proj.my-site.org.conf}}} with these contents:
    93 
    94 {{{
     337
     338Keep the file above your document root for security reasons.
     339
     340Create this file for example `/etc/apache2/sites-enabled/trac.my-proj.my-site.org.conf` on Ubuntu with the following content:
     341
     342{{{#!apache
    95343<Directory /home/trac-for-my-proj/the-deploy/cgi-bin/trac.wsgi>
    96344  WSGIApplicationGroup %{GLOBAL}
     
    113361}}}
    114362
    115 
    116 (for subdomains to work you would probably also need to alter /etc/hosts and add A-Records to your host's DNS.)
    117 
    118 == Trac with PostgreSQL ==
    119 
    120 When using the mod_wsgi adapter with multiple Trac instances and PostgreSQL (or MySQL?) as a database back-end the server can get a lot of open database connections. (and thus PostgreSQL processes)
    121 
    122 A workable solution is to disabled connection pooling in Trac. This is done by setting poolable = False in trac.db.postgres_backend on the PostgreSQLConnection class.
    123 
    124 But it's not necessary to edit the source of trac, the following lines in trac.wsgi will also work:
    125 
    126 {{{
    127 import trac.db.postgres_backend
    128 trac.db.postgres_backend.PostgreSQLConnection.poolable = False
    129 }}}
    130 
    131 Now Trac drops the connection after serving a page and the connection count on the database will be kept minimal.
    132 
    133 == Getting Trac to work nicely with SSPI and 'Require Group' ==
    134 If 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'.
    135 
    136 This WSGI script 'fixes' things, hope it helps:
    137 {{{
     363For subdomains to work you would probably also need to alter `/etc/hosts` and add A-Records to your host's DNS.
     364
     365== Troubleshooting
     366
     367=== Use a recent version
     368
     369Please 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 [https://code.google.com/archive/p/modwsgi/issues/100 #100] and [https://code.google.com/archive/p/modwsgi/issues/132 #132].
     370
     371'''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 0.11.2.1). Upgrading to Python 2.6.2 (as suggested [https://www.mail-archive.com/modwsgi@googlegroups.com/msg01917.html here]) solved this for me[[BR]]-- Graham Shanks
     372
     373If you plan to use `mod_wsgi` in embedded mode on Windows or with the MPM worker on Linux, then you will need version 3.4 or greater. See [trac:#10675] for details.
     374
     375=== Getting Trac to work nicely with SSPI and 'Require Group'
     376
     377If 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'.
     378
     379This WSGI script fixes that:
     380{{{#!python
    138381import os
    139382import trac.web.main
     
    147390    return trac.web.main.dispatch_request(environ, start_response)
    148391}}}
     392
     393=== Trac with PostgreSQL
     394
     395When 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.
     396
     397A 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.
     398
     399But it is not necessary to edit the source of Trac. The following lines in `trac.wsgi` will also work:
     400
     401{{{#!python
     402import trac.db.postgres_backend
     403trac.db.postgres_backend.PostgreSQLConnection.poolable = False
     404}}}
     405
     406or
     407
     408{{{#!python
     409import trac.db.mysql_backend
     410trac.db.mysql_backend.MySQLConnection.poolable = False
     411}}}
     412
     413Now Trac drops the connection after serving a page and the connection count on the database will be kept low.
     414
     415//This is not a recommended approach though. See also the notes at the bottom of the [https://code.google.com/archive/p/modwsgi/wikis/IntegrationWithTrac.wiki mod_wsgi's IntegrationWithTrac] wiki page.//
     416
     417=== Other resources
     418
     419For more troubleshooting tips, see also the [TracModPython#Troubleshooting mod_python troubleshooting] section, as most Apache-related issues are quite similar, plus discussion of potential [https://code.google.com/archive/p/modwsgi/wikis/ApplicationIssues.wiki application issues] when using mod_wsgi. The wsgi page also has a [https://code.google.com/archive/p/modwsgi/wikis/IntegrationWithTrac.wiki Integration With Trac] document.
     420
    149421----
    150 See also:  TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]
     422See also: TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]