Changes between Version 1 and Version 2 of TracModWSGI


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Timestamp:
Apr 24, 2017, 10:36:27 AM (4 months ago)
Author:
trac
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  • TracModWSGI

    v1 v2  
    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 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}}}
     20
     21=== A very basic script
     22
     23In its simplest form, the script could be:
     24
     25{{{#!python
    1126import os
    1227
     
    1833}}}
    1934
    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
     35The `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`.
     36
     37On Windows:
     38 - If run under the user's session, the Python Egg cache can be found in `%AppData%\Roaming`, for example:
     39{{{#!python
     40os.environ['PYTHON_EGG_CACHE'] = r'C:\Users\Administrator\AppData\Roaming\Python-Eggs'
     41}}}
     42 - If run under a Window service, you should create a directory for Python Egg cache:
     43{{{#!python
     44os.environ['PYTHON_EGG_CACHE'] = r'C:\Trac-Python-Eggs'
     45}}}
     46
     47=== A more elaborate script
     48
     49If 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.
     50
     51To solve this problem, use the following `.wsgi` file instead:
     52{{{#!python
    2653import os
    2754
     
    3461}}}
    3562
    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
     63For 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.
     64
     65If 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:
     66
     67{{{#!python
    4268import site
    4369site.addsitedir('/usr/local/trac/lib/python2.4/site-packages')
    4470}}}
    4571
    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 {{{
     72Change it according to the path you installed the Trac libs at.
     73
     74== Mapping requests to the script
     75
     76After preparing your .wsgi script, add the following to your Apache configuration file, typically `httpd.conf`:
     77
     78{{{#!apache
    5179WSGIScriptAlias /trac /usr/local/trac/mysite/apache/mysite.wsgi
    5280
    5381<Directory /usr/local/trac/mysite/apache>
    5482    WSGIApplicationGroup %{GLOBAL}
    55     Order deny,allow
    56     Allow from all
     83    # For Apache 2.2
     84    <IfModule !mod_authz_core.c>
     85        Order deny,allow
     86        Allow from all
     87    </IfModule>
     88    # For Apache 2.4
     89    <IfModule mod_authz_core.c>
     90        Require all granted
     91    </IfModule>
    5792</Directory>
    5893}}}
    5994
    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 {{{
     95Here, the script is in a subdirectory of the Trac environment.
     96
     97If you followed the directions [TracInstall#cgi-bin Generating the Trac cgi-bin directory], your Apache configuration file should look like following:
     98
     99{{{#!apache
     100WSGIScriptAlias /trac /usr/share/trac/cgi-bin/trac.wsgi
     101
     102<Directory /usr/share/trac/cgi-bin>
     103    WSGIApplicationGroup %{GLOBAL}
     104    # For Apache 2.2
     105    <IfModule !mod_authz_core.c>
     106        Order deny,allow
     107        Allow from all
     108    </IfModule>
     109    # For Apache 2.4
     110    <IfModule mod_authz_core.c>
     111        Require all granted
     112    </IfModule>
     113</Directory>
     114}}}
     115
     116In 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.
     117
     118To 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):
     119
     120{{{#!python
    65121def application(environ, start_response):
    66122        start_response('200 OK',[('Content-type','text/html')])
     
    68124}}}
    69125
    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 {{{
     126For 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.
     127
     128== Configuring Authentication
     129
     130The following sections describe different methods for setting up authentication. See also [http://httpd.apache.org/docs/2.4/howto/auth.html Authentication, Authorization and Access Control] in the Apache guide.
     131
     132=== Using Basic Authentication
     133
     134The simplest way to enable authentication with Apache is to create a password file. Use the `htpasswd` program as follows:
     135{{{#!sh
     136$ htpasswd -c /somewhere/trac.htpasswd admin
     137New password: <type password>
     138Re-type new password: <type password again>
     139Adding password for user admin
     140}}}
     141
     142After the first user, you don't need the "-c" option anymore:
     143{{{#!sh
     144$ htpasswd /somewhere/trac.htpasswd john
     145New password: <type password>
     146Re-type new password: <type password again>
     147Adding password for user john
     148}}}
     149
     150See the man page for `htpasswd` for full documentation.
     151
     152After you've created the users, you can set their permissions using TracPermissions.
     153
     154Now, you need to enable authentication against the password file in the Apache configuration:
     155{{{#!apache
     156<Location "/trac/login">
     157  AuthType Basic
     158  AuthName "Trac"
     159  AuthUserFile /somewhere/trac.htpasswd
     160  Require valid-user
     161</Location>
     162}}}
     163
     164If you are hosting multiple projects, you can use the same password file for all of them:
     165{{{#!apache
     166<LocationMatch "/trac/[^/]+/login">
     167  AuthType Basic
     168  AuthName "Trac"
     169  AuthUserFile /somewhere/trac.htpasswd
     170  Require valid-user
     171</LocationMatch>
     172}}}
     173
     174Note 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.
     175
     176=== Using Digest Authentication
     177
     178For better security, it is recommended that you either enable SSL or at least use the "digest" authentication scheme instead of "Basic".
     179
     180You have to create your `.htpasswd` file with the `htdigest` command instead of `htpasswd`, as follows:
     181{{{#!sh
     182$ htdigest -c /somewhere/trac.htpasswd trac admin
     183}}}
     184
     185The "trac" parameter above is the "realm", and will have to be reused in the Apache configuration in the !AuthName directive:
     186
     187{{{#!apache
     188<Location "/trac/login">
     189  AuthType Digest
     190  AuthName "trac"
     191  AuthDigestDomain /trac
     192  AuthUserFile /somewhere/trac.htpasswd
     193  Require valid-user
     194</Location>
     195}}}
     196
     197For multiple environments, you can use the same `LocationMatch` as described with the previous method.
     198
     199'''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.
     200
     201Don't forget to activate the mod_auth_digest. For example, on a Debian 4.0r1 (etch) system:
     202{{{#!apache
     203  LoadModule auth_digest_module /usr/lib/apache2/modules/mod_auth_digest.so
     204}}}
     205
     206See also the [https://httpd.apache.org/docs/2.4/mod/mod_auth_basic.html mod_auth_digest] documentation.
     207
     208=== Using LDAP Authentication
     209
     210Configuration 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).
     211
     2121. You need to load the following modules in Apache httpd.conf:
     213{{{#!apache
     214  LoadModule ldap_module modules/mod_ldap.so
     215  LoadModule authnz_ldap_module modules/mod_authnz_ldap.so
     216}}}
     2171. Your httpd.conf also needs to look something like:
     218{{{#!apache
     219<Location /trac/>
     220  # (if you're using it, mod_python specific settings go here)
     221  Order deny,allow
     222  Deny from all
     223  Allow from 192.168.11.0/24
     224  AuthType Basic
     225  AuthName "Trac"
     226  AuthBasicProvider "ldap"
     227  AuthLDAPURL "ldap://127.0.0.1/dc=example,dc=co,dc=ke?uid?sub?(objectClass=inetOrgPerson)"
     228  authzldapauthoritative Off
     229  Require valid-user
     230</Location>
     231}}}
     2321. You can use the LDAP interface as a way to authenticate to a Microsoft Active Directory. Use the following as your LDAP URL:
     233{{{#!apache
     234  AuthLDAPURL "ldap://directory.example.com:3268/DC=example,DC=com?sAMAccountName?sub?(objectClass=user)"
     235}}}
     236 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:
     237{{{#!apache
     238  AuthLDAPBindDN ldap-auth-user@example.com
     239  AuthLDAPBindPassword "password"
     240}}}
     241 The whole section looks like:
     242{{{#!apache
     243<Location /trac/>
     244  # (if you're using it, mod_python specific settings go here)
     245  Order deny,allow
     246  Deny from all
     247  Allow from 192.168.11.0/24
     248  AuthType Basic
     249  AuthName "Trac"
     250  AuthBasicProvider "ldap"
     251  AuthLDAPURL "ldap://adserver.company.com:3268/DC=company,DC=com?sAMAccountName?sub?(objectClass=user)"
     252  AuthLDAPBindDN       ldap-auth-user@company.com
     253  AuthLDAPBindPassword "the_password"
     254  authzldapauthoritative Off
     255  # require valid-user
     256  Require ldap-group CN=Trac Users,CN=Users,DC=company,DC=com
     257</Location>
     258}}}
     259
     260Note 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.
     261
     262Note 2: You can also require the user be a member of a certain LDAP group, instead of just having a valid login:
     263{{{#!apache
     264  Require ldap-group CN=Trac Users,CN=Users,DC=example,DC=com
     265}}}
     266
     267See also:
     268 - [https://httpd.apache.org/docs/2.4/mod/mod_authnz_ldap.html mod_authnz_ldap], documentation for mod_authnz_ldap.   
     269 - [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.
     270 - [https://trac-hacks.org/wiki/LdapPlugin TracHacks:LdapPlugin] for storing TracPermissions in LDAP.
     271
     272=== Using SSPI Authentication
     273
     274If 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:
     275{{{#!apache
     276<Location /trac/login>
     277  AuthType SSPI
     278  AuthName "Trac Login"
     279  SSPIAuth On
     280  SSPIAuthoritative On
     281  SSPIDomain MyLocalDomain
     282  SSPIOfferBasic On
     283  SSPIOmitDomain Off
     284  SSPIBasicPreferred On
     285  Require valid-user
     286</Location>
     287}}}
     288
     289Using 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.
     290
     291Some common problems with SSPI authentication: [trac:#1055], [trac:#1168] and [trac:#3338].
     292
     293See also [trac:TracOnWindows/Advanced].
     294
     295=== Using CA !SiteMinder Authentication
     296
     297Setup 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`:
     298{{{#!apache
     299RemoteUserVar="WHATEVER_IT_SHOULD_BE"
     300SetRemoteUser="YES"
     301}}}
     302
     303The 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.
     304
     305Also add a !LogOffUri parameter to the agent configuration, for example `/trac/logout`.
     306
     307Then 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`:
     308
     309{{{#!python
     310def application(environ, start_request):
     311    # Set authenticated username on CA SiteMinder to REMOTE_USER variable
     312    # strip() is used to remove any spaces on the end of the string
     313    if 'HTTP_SM_USER' in environ:
     314        environ['REMOTE_USER'] = environ['HTTP_REMOTE_USER'].strip()
     315    ...
     316}}}
     317
     318You do not need any Apache "Location" directives.
     319
     320=== Example: Apache/mod_wsgi with Basic Authentication, Trac being at the root of a virtual host
     321
     322Per the mod_wsgi documentation linked to above, here is an example Apache configuration that:
     323 - serves the Trac instance from a virtualhost subdomain
     324 - uses Apache basic authentication for Trac authentication.
     325
     326If 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:
     327
     328Create the htpasswd file:
     329{{{#!sh
    85330cd /home/trac-for-my-proj/the-env
    86331htpasswd -c htpasswd firstuser
     
    88333htpasswd htpasswd seconduser
    89334}}}
    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 {{{
     335
     336Keep the file above your document root for security reasons.
     337
     338Create this file for example `/etc/apache2/sites-enabled/trac.my-proj.my-site.org.conf` on Ubuntu with the following content:
     339
     340{{{#!apache
    95341<Directory /home/trac-for-my-proj/the-deploy/cgi-bin/trac.wsgi>
    96342  WSGIApplicationGroup %{GLOBAL}
     
    113359}}}
    114360
    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 {{{
     361For subdomains to work you would probably also need to alter `/etc/hosts` and add A-Records to your host's DNS.
     362
     363== Troubleshooting
     364
     365=== Use a recent version
     366
     367Please 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].
     368
     369'''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
     370
     371If 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.
     372
     373=== Getting Trac to work nicely with SSPI and 'Require Group'
     374
     375If 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'.
     376
     377This WSGI script fixes that:
     378{{{#!python
    138379import os
    139380import trac.web.main
     
    147388    return trac.web.main.dispatch_request(environ, start_response)
    148389}}}
     390
     391=== Trac with PostgreSQL
     392
     393When 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.
     394
     395A 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.
     396
     397But it is not necessary to edit the source of Trac. The following lines in `trac.wsgi` will also work:
     398
     399{{{#!python
     400import trac.db.postgres_backend
     401trac.db.postgres_backend.PostgreSQLConnection.poolable = False
     402}}}
     403
     404or
     405
     406{{{#!python
     407import trac.db.mysql_backend
     408trac.db.mysql_backend.MySQLConnection.poolable = False
     409}}}
     410
     411Now Trac drops the connection after serving a page and the connection count on the database will be kept low.
     412
     413//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.//
     414
     415=== Missing Headers and Footers
     416
     417If python optimizations are enabled, then headers and footers will not be rendered. An error will be raised in Trac 1.0.11 and later when optimizations are enabled.
     418
     419In your WSGI configuration file, the `WSGIPythonOptimize` setting must be set to `0` (`1` or `2` will not work):
     420
     421{{{#!apache
     422    WSGIPythonOptimize 0
     423}}}
     424
     425On Ubuntu, the WSGI mod configuration is at `/etc/apache2/mods-enabled/wsgi.conf`.
     426
     427The same issue is seen with `PythonOptimize On` in [TracModPython#Pagelayoutissues ModPython].
     428
     429=== Other resources
     430
     431For 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.
     432
    149433----
    150 See also:  TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]
     434See also: TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]