Changes between Version 1 and Version 2 of TracModWSGI


Ignore:
Timestamp:
Apr 16, 2016, 7:10:42 PM (9 years ago)
Author:
trac
Comment:

--

Legend:

Unmodified
Added
Removed
Modified

  • TracModWSGI

    v1 v2  
    1 = Trac and mod_wsgi =
    2 
    3 
    4 [http://code.google.com/p/modwsgi/ 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.
     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.
    54
    65[[PageOutline(2-3,Overview,inline)]]
    … …  
    87== The `trac.wsgi` script
    98
    10 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).
     9Trac can be run on top of mod_wsgi with the help of an application script, which is just 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 using the `TRAC_ENV_PARENT_DIR` in trac.wsgi:
     14{{{#!python
     15def application(environ, start_request):
     16    # Add this to config when you have multiple projects                                             
     17    environ.setdefault('trac.env_parent_dir', '/usr/share/trac/projects') 
     18    ..
     19}}}
    1120
    1221=== A very basic script
    … …  
    2332}}}
    2433
    25 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.
     34The `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`.
     35
     36On Windows:
     37 - If run under the user's session, the Python Egg cache can be found in `%AppData%\Roaming`, for example:
     38{{{#!python
     39os.environ['PYTHON_EGG_CACHE'] = r'C:\Users\Administrator\AppData\Roaming\Python-Eggs'
     40}}}
     41 - If run under a Window service, you should create a directory for Python Egg cache:
     42{{{#!python
     43os.environ['PYTHON_EGG_CACHE'] = r'C:\Trac-Python-Eggs'
     44}}}
    2645
    2746=== A more elaborate script
    2847
    29 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, as the variable may be filled with the path of a previously viewed Trac environment.
     48If 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.
    3049
    3150To solve this problem, use the following `.wsgi` file instead:
    … …  
    4362For 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.
    4463
    45 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 at the top of the wsgi script:
     64If 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:
    4665
    4766{{{#!python
    … …  
    5271Change it according to the path you installed the Trac libs at.
    5372
    54 === Recommended `trac.wsgi` script
    55 
    56 A 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).
    57 
    58 
    5973== Mapping requests to the script
    6074
    61 After you've done preparing your .wsgi script, add the following to your Apache configuration file (`httpd.conf` for example).
    62 
    63 {{{
     75After preparing your .wsgi script, add the following to your Apache configuration file, typically `httpd.conf`:
     76
     77{{{#!apache
    6478WSGIScriptAlias /trac /usr/local/trac/mysite/apache/mysite.wsgi
    6579
    6680<Directory /usr/local/trac/mysite/apache>
    6781    WSGIApplicationGroup %{GLOBAL}
    68     Order deny,allow
    69     Allow from all
     82    # For Apache 2.2
     83    <IfModule !mod_authz_core.c>
     84        Order deny,allow
     85        Allow from all
     86    </IfModule>
     87    # For Apache 2.4
     88    <IfModule mod_authz_core.c>
     89        Require all granted
     90    </IfModule>
    7091</Directory>
    7192}}}
    … …  
    7394Here, the script is in a subdirectory of the Trac environment.
    7495
    75 If you followed the directions [http://trac.edgewall.org/wiki/TracInstall#cgi-bin Generating the Trac cgi-bin directory], your Apache configuration file should look like following:
    76 
    77 {{{
     96If you followed the directions [TracInstall#cgi-bin Generating the Trac cgi-bin directory], your Apache configuration file should look like following:
     97
     98{{{#!apache
    7899WSGIScriptAlias /trac /usr/share/trac/cgi-bin/trac.wsgi
    79100
    80101<Directory /usr/share/trac/cgi-bin>
    81102    WSGIApplicationGroup %{GLOBAL}
    82     Order deny,allow
    83     Allow from all
     103    # For Apache 2.2
     104    <IfModule !mod_authz_core.c>
     105        Order deny,allow
     106        Allow from all
     107    </IfModule>
     108    # For Apache 2.4
     109    <IfModule mod_authz_core.c>
     110        Require all granted
     111    </IfModule>
    84112</Directory>
    85113}}}
    86114
    87 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 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.
     115In 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.
    88116
    89117To 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):
    … …  
    97125For more information about using the mod_wsgi specific directives, see the [http://code.google.com/p/modwsgi/wiki/ mod_wsgi's wiki] and more specifically the [http://code.google.com/p/modwsgi/wiki/IntegrationWithTrac IntegrationWithTrac] page.
    98126
    99 
    100127== Configuring Authentication
    101128
    102 We describe in the the following sections different methods for setting up authentication.
    103 
    104 See also [http://httpd.apache.org/docs/2.2/howto/auth.html Authentication, Authorization and Access Control] in the Apache guide.
    105 
    106 === Using Basic Authentication ===
    107 
    108 The simplest way to enable authentication with Apache is to create a password file. Use the `htpasswd` program to create the password file:
    109 {{{
     129The following sections describe different methods for setting up authentication. See also [http://httpd.apache.org/docs/2.2/howto/auth.html Authentication, Authorization and Access Control] in the Apache guide.
     130
     131=== Using Basic Authentication
     132
     133The simplest way to enable authentication with Apache is to create a password file. Use the `htpasswd` program as follows:
     134{{{#!sh
    110135$ htpasswd -c /somewhere/trac.htpasswd admin
    111136New password: <type password>
    … …  
    114139}}}
    115140
    116 After the first user, you dont need the "-c" option anymore:
    117 {{{
     141After the first user, you don't need the "-c" option anymore:
     142{{{#!sh
    118143$ htpasswd /somewhere/trac.htpasswd john
    119144New password: <type password>
    … …  
    126151After you've created the users, you can set their permissions using TracPermissions.
    127152
    128 Now, you'll need to enable authentication against the password file in the Apache configuration:
    129 {{{
     153Now, you need to enable authentication against the password file in the Apache configuration:
     154{{{#!apache
    130155<Location "/trac/login">
    131156  AuthType Basic
    … …  
    136161}}}
    137162
    138 If you're hosting multiple projects you can use the same password file for all of them:
    139 {{{
     163If you are hosting multiple projects, you can use the same password file for all of them:
     164{{{#!apache
    140165<LocationMatch "/trac/[^/]+/login">
    141166  AuthType Basic
    … …  
    148173See also the [http://httpd.apache.org/docs/2.2/mod/mod_auth_basic.html mod_auth_basic] documentation.
    149174
    150 === Using Digest Authentication ===
     175=== Using Digest Authentication
    151176
    152177For better security, it is recommended that you either enable SSL or at least use the “digest” authentication scheme instead of “Basic”.
    153178
    154 You'll have to create your `.htpasswd` file with the `htdigest` command instead of `htpasswd`, as follows:
    155 {{{
    156 # htdigest -c /somewhere/trac.htpasswd trac admin
     179You have to create your `.htpasswd` file with the `htdigest` command instead of `htpasswd`, as follows:
     180{{{#!sh
     181$ htdigest -c /somewhere/trac.htpasswd trac admin
    157182}}}
    158183
    159184The "trac" parameter above is the "realm", and will have to be reused in the Apache configuration in the !AuthName directive:
    160185
    161 {{{
     186{{{#!apache
    162187<Location "/trac/login">
    163 
    164     AuthType Digest
    165     AuthName "trac"
    166     AuthDigestDomain /trac
    167     AuthUserFile /somewhere/trac.htpasswd
    168     Require valid-user
     188  AuthType Digest
     189  AuthName "trac"
     190  AuthDigestDomain /trac
     191  AuthUserFile /somewhere/trac.htpasswd
     192  Require valid-user
    169193</Location>
    170194}}}
    … …  
    172196For multiple environments, you can use the same `LocationMatch` as described with the previous method.
    173197
     198'''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. '''
     199
    174200Don't forget to activate the mod_auth_digest. For example, on a Debian 4.0r1 (etch) system:
    175 {{{
    176     LoadModule auth_digest_module /usr/lib/apache2/modules/mod_auth_digest.so
    177 }}}
    178 
     201{{{#!apache
     202  LoadModule auth_digest_module /usr/lib/apache2/modules/mod_auth_digest.so
     203}}}
    179204
    180205See also the [http://httpd.apache.org/docs/2.2/mod/mod_auth_digest.html mod_auth_digest] documentation.
    … …  
    182207=== Using LDAP Authentication
    183208
    184 Configuration for [http://httpd.apache.org/docs/2.2/mod/mod_ldap.html mod_ldap] authentication in Apache is a bit tricky (httpd 2.2.x and OpenLDAP: slapd 2.3.19)
    185 
    186 1. You need to load the following modules in Apache httpd.conf
    187 {{{
    188 LoadModule ldap_module modules/mod_ldap.so
    189 LoadModule authnz_ldap_module modules/mod_authnz_ldap.so
    190 }}}
    191 
    192 2. Your httpd.conf also needs to look something like:
    193 
    194 {{{
     209Configuration for [http://httpd.apache.org/docs/2.2/mod/mod_ldap.html mod_ldap] authentication in Apache is more involved (httpd 2.2.x and OpenLDAP: slapd 2.3.19).
     210
     2111. You need to load the following modules in Apache httpd.conf:
     212{{{#!apache
     213  LoadModule ldap_module modules/mod_ldap.so
     214  LoadModule authnz_ldap_module modules/mod_authnz_ldap.so
     215}}}
     2161. Your httpd.conf also needs to look something like:
     217{{{#!apache
    195218<Location /trac/>
    196219  # (if you're using it, mod_python specific settings go here)
    … …  
    206229</Location>
    207230}}}
    208 
    209 
    210 3. You can use the LDAP interface as a way to authenticate to a Microsoft Active Directory:
    211 
    212 
    213 Use the following as your LDAP URL:
    214 {{{
    215     AuthLDAPURL "ldap://directory.example.com:3268/DC=example,DC=com?sAMAccountName?sub?(objectClass=user)"
    216 }}}
    217 
    218 You will also need to provide an account for Apache to use when checking
    219 credentials. As this password will be listed in plaintext in the
    220 config, you should be sure to use an account specifically for this task:
    221 {{{
    222     AuthLDAPBindDN ldap-auth-user@example.com
    223     AuthLDAPBindPassword "password"
    224 }}}
    225 
    226 The whole section looks like:
    227 {{{
     2311. You can use the LDAP interface as a way to authenticate to a Microsoft Active Directory. Use the following as your LDAP URL:
     232{{{#!apache
     233  AuthLDAPURL "ldap://directory.example.com:3268/DC=example,DC=com?sAMAccountName?sub?(objectClass=user)"
     234}}}
     235 You 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:
     236{{{#!apache
     237  AuthLDAPBindDN ldap-auth-user@example.com
     238  AuthLDAPBindPassword "password"
     239}}}
     240 The whole section looks like:
     241{{{#!apache
    228242<Location /trac/>
    229243  # (if you're using it, mod_python specific settings go here)
    … …  
    239253  authzldapauthoritative Off
    240254  # require valid-user
    241   require ldap-group CN=Trac Users,CN=Users,DC=company,DC=com
    242 </Location>
    243 }}}
    244 
    245 Note 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.
    246 
    247 Note 2: You can also require the user be a member of a certain LDAP group, instead of
    248 just having a valid login:
    249 {{{
    250     Require ldap-group CN=Trac Users,CN=Users,DC=example,DC=com
     255  Require ldap-group CN=Trac Users,CN=Users,DC=company,DC=com
     256</Location>
     257}}}
     258
     259Note 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.
     260
     261Note 2: You can also require the user be a member of a certain LDAP group, instead of just having a valid login:
     262{{{#!apache
     263  Require ldap-group CN=Trac Users,CN=Users,DC=example,DC=com
    251264}}}
    252265
    253266See also:
    254   - [http://httpd.apache.org/docs/2.2/mod/mod_authnz_ldap.html mod_authnz_ldap], documentation for mod_authnz_ldap
    255    
     267 - [http://httpd.apache.org/docs/2.2/mod/mod_authnz_ldap.html mod_authnz_ldap], documentation for mod_authnz_ldap.   
    256268 - [http://httpd.apache.org/docs/2.2/mod/mod_ldap.html mod_ldap], documentation for mod_ldap, which provides connection pooling and a shared cache.
    257269 - [http://trac-hacks.org/wiki/LdapPlugin TracHacks:LdapPlugin] for storing TracPermissions in LDAP.
    … …  
    259271=== Using SSPI Authentication
    260272
    261 If you are using Apache on Windows, you can use mod_auth_sspi to provide
    262 single-sign-on. Download the module from the !SourceForge [http://sourceforge.net/projects/mod-auth-sspi/ mod-auth-sspi project] and then add the
    263 following to your !VirtualHost:
    264 {{{
    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>
    276 }}}
    277 
    278 Using the above, usernames in Trac will be of the form `DOMAIN\username`, so
    279 you may have to re-add permissions and such. If you do not want the domain to
    280 be part of the username, set `SSPIOmitDomain On` instead.
     273If you are using Apache on Windows, you can use mod_auth_sspi to provide single-sign-on. Download the module from the !SourceForge [http://sourceforge.net/projects/mod-auth-sspi/ mod-auth-sspi project] and then add the following to your !VirtualHost:
     274{{{#!apache
     275<Location /trac/login>
     276  AuthType SSPI
     277  AuthName "Trac Login"
     278  SSPIAuth On
     279  SSPIAuthoritative On
     280  SSPIDomain MyLocalDomain
     281  SSPIOfferBasic On
     282  SSPIOmitDomain Off
     283  SSPIBasicPreferred On
     284  Require valid-user
     285</Location>
     286}}}
     287
     288Using 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.
    281289
    282290Some common problems with SSPI authentication: [trac:#1055], [trac:#1168] and [trac:#3338].
    … …  
    284292See also [trac:TracOnWindows/Advanced].
    285293
     294=== Using CA !SiteMinder Authentication
     295Setup CA !SiteMinder to protect your Trac login URL (e.g. /trac/login).  Then modify the trac.wsgi script generated using `trac-admin <env> deploy <dir>` to add the following lines, which extract the HTTP_SM_USER variable and set it to REMOTE_USER:
     296
     297{{{#!python
     298def application(environ, start_request):
     299    # Set authenticated username on CA SiteMinder to REMOTE_USER variable
     300    # strip() is used to remove any spaces on the end of the string
     301    if 'HTTP_SM_USER' in environ:
     302        environ['REMOTE_USER'] = environ['HTTP_SM_USER'].strip()
     303    ...
     304}}}
     305
     306Note:  you do not need any Apache "Location" directives.
     307
    286308=== Using Apache authentication with the Account Manager plugin's Login form ===
    287309
    … …  
    291313
    292314Here is an example (from the !HttpAuthStore link) using acct_mgr-0.4 for hosting a single project:
    293 {{{
     315{{{#!ini
    294316[components]
    295317; be sure to enable the component
    … …  
    302324}}}
    303325This will generally be matched with an Apache config like:
    304 {{{
     326{{{#!apache
    305327<Location /authFile>
    306328   …HTTP authentication configuration…
    … …  
    308330</Location>
    309331}}}
    310 Note that '''authFile''' need not exist. See the !HttpAuthStore link above for examples where multiple Trac projects are hosted on a server.
     332Note 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.
    311333
    312334=== Example: Apache/mod_wsgi with Basic Authentication, Trac being at the root of a virtual host
    313335
    314 Per 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.
    315 
     336Per the mod_wsgi documentation linked to above, here is an example Apache configuration that:
     337 - serves the Trac instance from a virtualhost subdomain
     338 - uses Apache basic authentication for Trac authentication.
    316339
    317340If 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 first:
    318341
    319342Create the htpasswd file:
    320 {{{
     343{{{#!sh
    321344cd /home/trac-for-my-proj/the-env
    322345htpasswd -c htpasswd firstuser
    … …  
    324347htpasswd htpasswd seconduser
    325348}}}
    326 (keep the file above your document root for security reasons)
    327 
    328 Create this file e.g. (ubuntu) `/etc/apache2/sites-enabled/trac.my-proj.my-site.org.conf` with the following contents:
    329 
    330 {{{
     349Keep the file above your document root for security reasons.
     350
     351Create this file e.g. (ubuntu) `/etc/apache2/sites-enabled/trac.my-proj.my-site.org.conf` with the following content:
     352
     353{{{#!apache
    331354<Directory /home/trac-for-my-proj/the-deploy/cgi-bin/trac.wsgi>
    332355  WSGIApplicationGroup %{GLOBAL}
    … …  
    351374Note: for subdomains to work you would probably also need to alter `/etc/hosts` and add A-Records to your host's DNS.
    352375
    353 
    354376== Troubleshooting
    355377
    356378=== Use a recent version
    357379
    358 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. Another frequent symptom is that binary attachment downloads are truncated. 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].
     380Please 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 [http://code.google.com/p/modwsgi/issues/detail?id=100 #100] and [http://code.google.com/p/modwsgi/issues/detail?id=132 #132].
    359381
    360382''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''
    361383
    362 If 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).
    363 
    364 === Getting Trac to work nicely with SSPI and 'Require Group' ===
    365 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'.
    366 
    367 This WSGI script 'fixes' things, hope it helps:
     384If 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.
     385
     386=== Getting Trac to work nicely with SSPI and 'Require Group'
     387
     388If 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'.
     389
     390This WSGI script 'fixes' that:
    368391{{{#!python
    369392import os
    … …  
    379402}}}
    380403
    381 
    382 === Trac with PostgreSQL ===
    383 
    384 When 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.
    385 
    386 A 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.
    387 
    388 But it's not necessary to edit the source of Trac, the following lines in `trac.wsgi` will also work:
    389 
    390 {{{
     404=== Trac with PostgreSQL
     405
     406When 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.
     407
     408A 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.
     409
     410But it is not necessary to edit the source of Trac. The following lines in `trac.wsgi` will also work:
     411
     412{{{#!python
    391413import trac.db.postgres_backend
    392414trac.db.postgres_backend.PostgreSQLConnection.poolable = False
    … …  
    395417or
    396418
    397 {{{
     419{{{#!python
    398420import trac.db.mysql_backend
    399421trac.db.mysql_backend.MySQLConnection.poolable = False
    400422}}}
    401423
    402 Now Trac drops the connection after serving a page and the connection count on the database will be kept minimal.
     424Now Trac drops the connection after serving a page and the connection count on the database will be kept low.
    403425
    404426//This is not a recommended approach though. See also the notes at the bottom of the [http://code.google.com/p/modwsgi/wiki/IntegrationWithTrac mod_wsgi's IntegrationWithTrac] wiki page.//
    … …  
    408430For more troubleshooting tips, see also 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. The wsgi page also has a [http://code.google.com/p/modwsgi/wiki/IntegrationWithTrac Integration With Trac] document.
    409431
    410 
    411432----
    412 See also:  TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]
     433See also: TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]