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Changes between Version 5 and Version 6 of TracModPython

Timestamp:: Feb 4, 2019, 2:49:58 PM (6 years ago)
Author:: trac
Comment:: --

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TracModPython

-              v5
+              v6
+[[TracGuideToc]]
 = Trac and mod_python
-[[TracGuideToc]]
 Mod_python is an [https://httpd.apache.org/ Apache] module that embeds the Python interpreter within the server, so that web-based applications in Python will run many times faster than traditional CGI and will have the ability to retain database connections.
 Trac supports [http://www.modpython.org/ mod_python], which speeds up Trac's response times considerably, especially compared to [TracCgi CGI], and permits use of many Apache features not possible with [wiki:TracStandalone tracd]/mod_proxy.
-These instructions are for Apache 2. If you are using Apache 1.3, you may have some luck with [trac:wiki:TracModPython2.7 TracModPython2.7], but that is a deprecated setup.
 [[PageOutline(2-3,Overview,inline)]]
 == Simple configuration: single project == #Simpleconfiguration
+== Simple configuration: single project #Simpleconfiguration
 If you just installed mod_python, you may have to add a line to load the module in the Apache configuration:
 {{{
+{{{#!apache
 LoadModule python_module modules/mod_python.so
 }}}
 ''Note: The exact path to the module depends on how the HTTPD installation is laid out.''
+'''Note''': The exact path to the module depends on how the HTTPD installation is laid out.
 On Debian using apt-get:
 {{{
+{{{#!sh
 apt-get install libapache2-mod-python libapache2-mod-python-doc
 }}}
 Still on Debian, after you have installed mod_python, you must enable the modules in apache2, equivalent to the above Load Module directive:
 {{{
+{{{#!sh
 a2enmod python
 }}}
 On Fedora use, using yum:
 {{{
+{{{#!sh
 yum install mod_python
 }}}
 You can test your mod_python installation by adding the following to your httpd.conf. You should remove this when you are done testing for security reasons. Note: mod_python.testhandler is only available in mod_python 3.2+.
+{{{
+#!xml
+{{{#!apache
 <Location /mpinfo>
+   SetHandler mod_python
+   PythonInterpreter main_interpreter
+   PythonHandler mod_python.testhandler
+   Order allow,deny
+   Allow from all
+  SetHandler mod_python
+  PythonInterpreter main_interpreter
+  PythonHandler mod_python.testhandler
+  # For Apache 2.2
+  <IfModule !mod_authz_core.c>
+    Order allow,deny
+    Allow from all
+  </IfModule>
+  # For Apache 2.4
+  <IfModule mod_authz_core.c>
+    Require all granted
+  </IfModule>
 </Location>
 }}}
 A simple setup of Trac on mod_python looks like this:
+{{{
+#!xml
+{{{#!apache
 <Location /projects/myproject>
+   SetHandler mod_python
+   PythonInterpreter main_interpreter
+   PythonHandler trac.web.modpython_frontend
+   PythonOption TracEnv /var/trac/myproject
+   PythonOption TracUriRoot /projects/myproject
+   Order allow,deny
+   Allow from all
+  SetHandler mod_python
+  PythonInterpreter main_interpreter
+  PythonHandler trac.web.modpython_frontend
+  PythonOption TracEnv /var/trac/myproject
+  PythonOption TracUriRoot /projects/myproject
+  # For Apache 2.2
+  <IfModule !mod_authz_core.c>
+    Order allow,deny
+    Allow from all
+  </IfModule>
+  # For Apache 2.4
+  <IfModule mod_authz_core.c>
+    Require all granted
+  </IfModule>
 </Location>
 }}}
 …
 The options available are:
 {{{
     # For a single project
     PythonOption TracEnv /var/trac/myproject
     # For multiple projects
     PythonOption TracEnvParentDir /var/trac/myprojects
     # For the index of multiple projects
     PythonOption TracEnvIndexTemplate /srv/www/htdocs/trac/project_list_template.html
     # A space delimitted list, with a "," between key and value pairs.
     PythonOption TracTemplateVars key1,val1 key2,val2
     # Useful to get the date in the wanted order
     PythonOption TracLocale en_GB.UTF8
     # See description above
     PythonOption TracUriRoot /projects/myproject
+{{{#!apache
+# For a single project
+PythonOption TracEnv /var/trac/myproject
+# For multiple projects
+PythonOption TracEnvParentDir /var/trac/myprojects
+# For the index of multiple projects
+PythonOption TracEnvIndexTemplate /srv/www/htdocs/trac/project_list_template.html
+# A space delimitted list, with a "," between key and value pairs.
+PythonOption TracTemplateVars key1,val1 key2,val2
+# Useful to get the date in the wanted order
+PythonOption TracLocale en_GB.UTF8
+# See description above
+PythonOption TracUriRoot /projects/myproject
 }}}
 === Python Egg Cache
 Compressed python eggs like Genshi are normally extracted into a directory named `.python-eggs` in the users home directory. Since apache's home usually is not writable, an alternate egg cache directory can be specified like this:
 {{{
+Compressed Python eggs like Genshi are normally extracted into a directory named `.python-eggs` in the users home directory. Since Apache's home usually is not writeable, an alternate egg cache directory can be specified like this:
+{{{#!apache
 PythonOption PYTHON_EGG_CACHE /var/trac/myprojects/egg-cache
 }}}
 or you can uncompress the Genshi egg to resolve problems extracting from it.
+Or you can uncompress the Genshi egg to resolve problems extracting from it.
 === Configuring Authentication
 …
 === Setting the Python Egg Cache
+If the Egg Cache isn't writeable by your Web server, you'll either have to change the permissions, or point Python to a location where Apache can write. This can manifest itself as a ''500 internal server error'' and/or a complaint in the syslog.
+{{{
+#!xml
+If the Egg Cache isn't writeable by your Web server, you'll either have to change the permissions, or point Python to a location where Apache can write. This can manifest itself as a `500 internal server error` and/or a complaint in the syslog.
+{{{#!apache
 <Location /projects/myproject>
   ...
 …
 === Setting the !PythonPath
+If the Trac installation isn't installed in your Python path, you'll have to tell Apache where to find the Trac mod_python handler  using the `PythonPath` directive:
+{{{
+#!xml
+If the Trac installation isn't installed in your Python path, you will have to tell Apache where to find the Trac mod_python handler  using the `PythonPath` directive:
+{{{#!apache
 <Location /projects/myproject>
   ...
 …
 The Trac mod_python handler supports a configuration option similar to Subversion's `SvnParentPath`, called `TracEnvParentDir`:
+{{{
+#!xml
+{{{#!apache
 <Location /projects>
   SetHandler mod_python
 …
 If you don't want to have the subdirectory listing as your projects home page you can use a
+{{{
+#!xml
+{{{#!apache
 <LocationMatch "/.+/">
 }}}
 …
 You can also use the same authentication realm for all of the projects using a `<LocationMatch>` directive:
+{{{
+#!xml
+{{{#!apache
 <LocationMatch "/projects/[^/]+/login">
   AuthType Basic
 …
 === Virtual Host Configuration
+Below is the sample configuration required to set up your trac as a virtual server, ie when you access it at the URLs like
+!http://trac.mycompany.com:
+{{{
+#!xml
+<VirtualHost * >
+Below is the sample configuration required to set up your Trac as a virtual server, ie when you access it at the URLs like
+`http://trac.mycompany.com`:
+{{{#!apache
+<VirtualHost *>
     DocumentRoot /var/www/myproject
     ServerName trac.mycompany.com
 …
 This does not seem to work in all cases. What you can do if it does not:
  * Try using `<LocationMatch>` instead of `<Location>`
  * <Location /> may, in your server setup, refer to the complete host instead of simple the root of the server. This means that everything (including the login directory referenced below) will be sent to python and authentication does not work (i.e. you get the infamous Authentication information missing error). If this applies to you, try using a sub-directory for trac instead of the root, ie /web/ and /web/login instead of / and /login.
+ * Try using `<LocationMatch>` instead of `<Location>`.
+ * `<Location />` may, in your server setup, refer to the complete host instead of simple the root of the server. This means that everything (including the login directory referenced below) will be sent to Python and authentication does not work, ie you get the infamous Authentication information missing error. If this is the case, try using a sub-directory for Trac instead of the root, ie /web/ and /web/login instead of / and /login.
  * Depending on apache's `NameVirtualHost` configuration, you may need to use `<VirtualHost *:80>` instead of `<VirtualHost *>`.
 For a virtual host that supports multiple projects replace "`TracEnv`" /var/trac/myproject with "`TracEnvParentDir`" /var/trac/
 Note: !DocumentRoot should not point to your Trac project env. As Asmodai wrote on #trac: "suppose there's a webserver bug that allows disclosure of !DocumentRoot they could then leech the entire Trac environment".
+For a virtual host that supports multiple projects replace `TracEnv /var/trac/myproject` with `TracEnvParentDir /var/trac`.
+'''Note''': !DocumentRoot should not point to your Trac project env. As Asmodai wrote on #trac: "suppose there's a webserver bug that allows disclosure of !DocumentRoot they could then leech the entire Trac environment".
 == Troubleshooting
+In general, if you get server error pages, you can either check the Apache error log, or enable the `PythonDebug` option:
+{{{
+#!xml
+If you get server error pages, you can either check the Apache error log, or enable the `PythonDebug` option:
+{{{#!apache
 <Location /projects/myproject>
   ...
 …
 If you've used `<Location />` directive, it will override any other directives, as well as `<Location /login>`.
 The workaround is to use negation expression as follows (for multi project setups):
+{{{
+#!xml
+{{{#!apache
 #this one for other pages
 <Location ~ "/*(?!login)">
 …
    PythonOption TracEnvParentDir /projects
    PythonOption TracUriRoot /
+</Location>
+</Location>
 #this one for login page
 <Location ~ "/[^/]+/login">
 …
 === Problem with zipped egg
 It's possible that your version of mod_python will not import modules from zipped eggs. If you encounter an `ImportError: No module named trac` in your Apache logs but you think everything is where it should be, this might be your problem. Look in your site-packages directory; if the Trac module appears as a ''file'' rather than a ''directory'', then this might be your problem. To rectify, try installing Trac using the `--always-unzip` option, like this:
 {{{
+It's possible that your version of mod_python will not import modules from zipped eggs. If you encounter an `ImportError: No module named trac` in your Apache logs but you think everything is where it should be, this might be your problem. Look in your site-packages directory; if the Trac module appears as a ''file'' rather than a ''directory'', then this might be your problem. To rectify this, try installing Trac using the `--always-unzip` option:
+{{{#!sh
 easy_install --always-unzip Trac-0.12b1.zip
 }}}
 …
 This also works out-of-box, with following trivial config:
 {{{#!xml
+{{{#!apache
 SetHandler mod_python
 PythonInterpreter main_interpreter
 …
 }}}
 The `TracUriRoot` is obviously the path you need to enter to the browser to get to Trac, eg domain.tld/projects/trac.
+The `TracUriRoot` is obviously the path you need to enter to the browser to get to Trac, eg `domain.tld/projects/trac`.
 === Additional .htaccess help
 If you are using the .htaccess method you may have additional problems if your trac directory is inheriting .htaccess directives from another. This may also help to add to your .htaccess file:
 {{{
+If you are using the .htaccess method you may have additional problems if your Trac directory is inheriting .htaccess directives from another. This may also help to add to your .htaccess file:
+{{{#!apache
 <IfModule mod_rewrite.c>
   RewriteEngine Off
 …
 ==== Win32 Issues
 If you run trac with mod_python < 3.2 on Windows, uploading attachments will '''not''' work. This problem is resolved in mod_python 3.1.4 or later, so please upgrade mod_python to fix this.
+If you run Trac with mod_python < 3.2 on Windows, uploading attachments will '''not''' work. This problem is resolved in mod_python 3.1.4 or later, so please upgrade mod_python to fix this.
 ==== OS X issues
 When using mod_python on OS X you will not be able to restart Apache using `apachectl restart`. This is apparently fixed in mod_python 3.2, so please upgrade.
+When using mod_python on OS X you will not be able to restart Apache using `apachectl restart`. This is apparently fixed in mod_python 3.2, so please upgrade mod_python to fix this.
 ==== SELinux issues
+If Trac reports something like: ''Cannot get shared lock on db.lock''
+The security context on the repository may need to be set:
+{{{
+If Trac reports something like: `Cannot get shared lock on db.lock`, then the security context on the repository may need to be set:
+{{{#!sh
 chcon -R -h -t httpd_sys_content_t PATH_TO_REPOSITORY
 }}}
 …
 ==== FreeBSD issues
+The FreeBSD ports have both the new and old versions of mod_python and SQLite, but earlier versions of pysqlite and mod_python won't integrate as the former requires threaded support in Python, and the latter requires a threadless install.
+If you compiled and installed apache2, threads are not automatically supported on FreeBSD. You could force thread support when running `./configure` for Apache, using `--enable-threads`, but this isn´t recommended.
+The FreeBSD ports have both the new and old versions of mod_python and SQLite, but earlier versions of pysqlite and mod_python won't integrate:
+ * pysqlite requires threaded support in Python
+ * mod_python requires a threadless install.
+Apache2 does not automatically support threads on FreeBSD. You could force thread support when running `./configure` for Apache, using `--enable-threads`, but this isn´t recommended.
 The best option [http://modpython.org/pipermail/mod_python/2006-September/021983.html seems to be] adding to /usr/local/apache2/bin/ennvars the line:
 {{{
+{{{#!sh
 export LD_PRELOAD=/usr/lib/libc_r.so
 }}}
 …
 ==== Fedora 7 Issues
 Make sure you install the 'python-sqlite2' package as it seems to be required for TracModPython but not for tracd.
+Make sure you install the 'python-sqlite2' package as it seems to be required for TracModPython, but not for tracd.
 === Subversion issues
 If you get the following Trac error `Unsupported version control system "svn"` only under mod_python, though it works well on the command-line and even with TracStandalone, chances are that you forgot to add the path to the Python bindings with the [TracModPython#ConfiguringPythonPath PythonPath] directive. The better way is to add a link to the bindings in the Python `site-packages` directory, or create a `.pth` file in that directory.
 If this is not the case, it's possible that you're using Subversion libraries that are binary incompatible with the Apache ones and an incompatibility of the `apr` libraries is usually the cause. In that case, you also won't be able to use the svn modules for Apache (`mod_dav_svn`).
+If you get the following Trac error `Unsupported version control system "svn"` only under mod_python, though it works well on the command-line and even with TracStandalone, chances are that you forgot to add the path to the Python bindings with the [TracModPython#ConfiguringPythonPath PythonPath] directive. A better way is to add a link to the bindings in the Python `site-packages` directory, or create a `.pth` file in that directory.
+If this is not the case, it's possible that you are using Subversion libraries that are binary incompatible with the Apache ones and an incompatibility of the `apr` libraries is usually the cause. In that case, you also won't be able to use the svn modules for Apache (`mod_dav_svn`).
 You also need a recent version of `mod_python` in order to avoid a runtime error ({{{argument number 2: a 'apr_pool_t *' is expected}}}) due to the default usage of multiple sub-interpreters. Version 3.2.8 ''should'' work, though it's probably better to use the workaround described in [trac:#3371 #3371], in order to force the use of the main interpreter:
 {{{
+{{{#!apache
 PythonInterpreter main_interpreter
 }}}
 This is anyway the recommended workaround for other well-known issues seen when using the Python bindings for Subversion within mod_python ([trac:#2611 #2611], [trac:#3455 #3455]). See in particular Graham Dumpleton's comment in [trac:comment:9:ticket:3455 #3455] explaining the issue.
+This is also the recommended workaround for other issues seen when using the Python bindings for Subversion within mod_python ([trac:#2611 #2611], [trac:#3455 #3455]). See in particular Graham Dumpleton's comment in [trac:comment:9:ticket:3455 #3455] explaining the issue.
 === Page layout issues
+If the formatting of the Trac pages look weird, chances are that the style sheets governing the page layout are not handled properly by the web server. Try adding the following lines to your apache configuration:
+{{{
+#!xml
+If the formatting of the Trac pages look weird, chances are that the style sheets governing the page layout are not handled properly by the web server. Try adding the following lines to your Apache configuration:
+{{{#!apache
 Alias /myproject/css "/usr/share/trac/htdocs/css"
 <Location /myproject/css>
 …
 }}}
 Note: For the above configuration to have any effect it must be put after the configuration of your project root location, i.e. {{{<Location /myproject />}}}.
 Also, setting `PythonOptimize On` seems to mess up the page headers and footers, in addition to hiding the documentation for macros and plugins (see #Trac8956). Considering how little effect the option has, leave it `Off`.
+'''Note''': For the above configuration to have any effect it must be put after the configuration of your project root location, ie {{{<Location /myproject />}}}.
+**Note:** Do not enable python optimizations using the directive `PythonOptimize On`. When optimizations are enabled the page header/footer and documentation for macros and plugins will be hidden. An error will be raised in Trac 1.0.11 and later when optimizations are enabled.
 === HTTPS issues
+If you want to run Trac fully under https you might find that it tries to redirect to plain http. In this case just add the following line to your apache configuration:
+{{{
+#!xml
+<VirtualHost * >
+If you want to run Trac fully under https you might find that it tries to redirect to plain http. In this case just add the following line to your Apache configuration:
+{{{#!apache
+<VirtualHost *>
     DocumentRoot /var/www/myproject
     ServerName trac.mycompany.com
 …
 You may encounter segfaults (reported on Debian etch) if php5-mhash module is installed. Try to remove it to see if this solves the problem. See [http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=411487 Debian bug report].
 Some people also have troubles when using php5 compiled with its own 3rd party libraries instead of system libraries. Check [http://www.djangoproject.com/documentation/modpython/#if-you-get-a-segmentation-fault Django segmentation fault].
+Some people also have troubles when using PHP5 compiled with its own third party libraries instead of system libraries. Check [http://www.djangoproject.com/documentation/modpython/#if-you-get-a-segmentation-fault Django segmentation fault].
 ----