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Changes between Version 9 and Version 10 of TracPlugins

Timestamp:: 25/03/2015 10:37:42 (10 years ago)
Author:: trac
Comment:: --

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TracPlugins

-              v9
+              v10
+= Trac plugins =
+= Trac plugins
 [[TracGuideToc]]
 From version 0.9 onwards, Trac is extensible with [trac:PluginList plugins]. Plugin functionality is based on the [trac:TracDev/ComponentArchitecture component architecture], with peculiarities described in the [TracDev/PluginDevelopment plugin development] page.
 == Plugin discovery ==
+Trac is extensible with [trac:PluginList plugins]. Plugin functionality is based on the [trac:TracDev/ComponentArchitecture component architecture], with peculiarities described in the [trac:TracDev/PluginDevelopment plugin development] page.
+== Plugin discovery
 From the user's point of view, a plugin is either a standalone .py file or an .egg package. Trac looks for plugins in the global shared plugins directory (see [TracIni#GlobalConfiguration Global Configuration]) and in the `plugins` directory of the local TracEnvironment. Components defined in globally-installed plugins should be explicitly enabled in the [[TracIni#components-section| [components] ]] section of the trac.ini file.
 == Requirements for Trac eggs ==
+== Requirements for Trac eggs
 To use egg-based plugins in Trac, you need to have [http://peak.telecommunity.com/DevCenter/setuptools setuptools] (version 0.6) installed.
 …
 To install `setuptools`, download the bootstrap module [http://peak.telecommunity.com/dist/ez_setup.py ez_setup.py] and execute it as follows:
 {{{
+{{{#!sh
 $ python ez_setup.py
 }}}
 …
 Plugins can also consist of a single `.py` file dropped directly into either the project's or the shared `plugins` directory.
 == Installing a Trac plugin ==
 === For a single project ===
+== Installing a Trac plugin
+=== For a single project
 Plugins are typically packaged as [http://peak.telecommunity.com/DevCenter/PythonEggs Python eggs]. That means they are .zip archives with the file extension `.egg`.
 …
  * Run:
 {{{
+{{{#!sh
 $ python setup.py bdist_egg
 }}}
 You should have a *.egg file. Examine the output of running python to find where this was created.
+You should have a *.egg file. Examine the output of running Python to find where this was created.
 Once you have the plugin archive, copy it into the `plugins` directory of the [wiki:TracEnvironment project environment]. Also, make sure that the web server has sufficient permissions to read the plugin egg. Then restart the web server. If you are running as a [wiki:TracStandalone "tracd" standalone server], restart tracd (kill and run again).
 …
 To uninstall a plugin installed this way, remove the egg from the `plugins` directory and restart the web server.
 Note: the Python version that the egg is built with ''must'' match the Python version with which Trac is run. For example, if you're running Trac under Python 2.5, but have upgraded your standalone Python to 2.6, the eggs won't be recognized.
 Note also: in a multi-project setup, a pool of Python interpreter instances will be dynamically allocated to projects based on need; since plugins occupy a place in Python's module system, the first version of any given plugin to be loaded will be used for all projects. In other words, you cannot use different versions of a single plugin in two projects of a multi-project setup. It may be safer to install plugins for all projects (see below), and then enable them selectively on a project-by-project basis.
 === For all projects ===
 ==== With an .egg file ====
 Some plugins (such as [trac:SpamFilter SpamFilter]) are downloadable as an `.egg` file that can be installed with the `easy_install` program:
 {{{
 easy_install TracSpamFilter
 }}}
 If `easy_install` is not on your system, see the Requirements section above to install it. Windows users will need to add the `Scripts` directory of their Python installation (for example, `C:\Python24\Scripts`) to their `PATH` environment variable (see [http://peak.telecommunity.com/DevCenter/EasyInstall#windows-notes easy_install Windows notes] for more information).
+'''Note''': the Python version that the egg is built with ''must'' match the Python version with which Trac is run. For example, if you're running Trac under Python 2.5, but have upgraded your standalone Python to 2.6, the eggs won't be recognized.
+'''Note''': in a multi-project setup, a pool of Python interpreter instances will be dynamically allocated to projects based on need; since plugins occupy a place in Python's module system, the first version of any given plugin to be loaded will be used for all projects. In other words, you cannot use different versions of a single plugin in two projects of a multi-project setup. It may be safer to install plugins for all projects (see below), and then enable them selectively on a project-by-project basis.
+=== For all projects
+==== With an .egg file
+Some plugins, such as [trac:SpamFilter SpamFilter], are downloadable as an `.egg` file that can be installed with `easy_install`:
+{{{#!sh
+$ easy_install TracSpamFilter
+}}}
+If `easy_install` is not on your system, see the Requirements section above to install it. Windows users will need to add the `Scripts` directory of their Python installation (for example, `C:\Python24\Scripts`) to their `PATH` environment variable. See [http://peak.telecommunity.com/DevCenter/EasyInstall#windows-notes easy_install Windows notes] for more information.
 If Trac reports permission errors after installing a zipped egg, and you would rather not bother providing a egg cache directory writable by the web server, you can get around it by simply unzipping the egg. Just pass `--always-unzip` to `easy_install`:
 {{{
 easy_install --always-unzip TracSpamFilter-0.4.1_r10106-py2.6.egg
+{{{#!sh
+$ easy_install --always-unzip TracSpamFilter-0.4.1_r10106-py2.6.egg
 }}}
 You should end up with a directory having the same name as the zipped egg (complete with `.egg` extension) and containing its uncompressed contents.
 Trac also searches for plugins installed in the shared plugins directory ''(since 0.10)''; see TracIni#GlobalConfiguration. This is a convenient way to share the installation of plugins across several, but not all, environments.
 ==== From source ====
+Trac also searches for plugins installed in the shared plugins directory, see TracIni#GlobalConfiguration. This is a convenient way to share the installation of plugins across several, but not all, environments.
+==== From source
 `easy_install` makes installing from source a snap. Just give it the URL to either a Subversion repository or a tarball/zip of the source:
 {{{
 easy_install http://svn.edgewall.com/repos/trac/plugins/0.12/spam-filter-captcha
 }}}
 ==== Enabling the plugin ====
 Unlike plugins installed per-environment, you'll have to explicitly enable globally installed plugins via [wiki:TracIni trac.ini]. This also applies to plugins installed in the shared plugins directory, i.e. the path specified in the `[inherit] plugins_dir` configuration option.
+{{{#!sh
+$ easy_install http://svn.edgewall.com/repos/trac/plugins/0.12/spam-filter-captcha
+}}}
+==== Enabling the plugin
+Unlike plugins installed per-environment, you'll have to explicitly enable globally installed plugins via [wiki:TracIni trac.ini]. This also applies to plugins installed in the shared plugins directory, ie the path specified in the `[inherit] plugins_dir` configuration option.
 This is done in the `[components]` section of the configuration file. For example:
 {{{
+{{{#!ini
 [components]
 tracspamfilter.* = enabled
 …
 The name of the option is the Python package of the plugin. This should be specified in the documentation of the plugin, but can also be easily discovered by looking at the source (look for a top-level directory that contains a file named `__init__.py`).
 Note: After installing the plugin, you must restart your web server.
 ==== Uninstalling ====
+After installing the plugin, you must restart your web server.
+==== Uninstalling
 `easy_install` or `python setup.py` does not have an uninstall feature. Hower, it is usually quite trivial to remove a globally-installed egg and reference:
 …
 If you are uncertain about the location of the egg, here's a small tip to help locate an egg (or any package). Just replace `myplugin` with whatever namespace the plugin uses (as used when enabling the plugin):
 {{{
+{{{#!pycon
 >>> import myplugin
 >>> print myplugin.__file__
 …
 }}}
 == Setting up the plugin cache ==
+== Setting up the plugin cache
 Some plugins will need to be extracted by the Python eggs runtime (`pkg_resources`), so that their contents are actual files on the file system. The directory in which they are extracted defaults to `.python-eggs` in the home directory of the current user, which may or may not be a problem. You can, however, override the default location using the `PYTHON_EGG_CACHE` environment variable.
 To do this from the Apache configuration, use the `SetEnv` directive:
 {{{
+{{{#!apache
 SetEnv PYTHON_EGG_CACHE /path/to/dir
 }}}
 This works whether you're using the [wiki:TracCgi CGI] or the [wiki:TracModPython mod_python] front-end. Put this directive next to where you set the path to the [wiki:TracEnvironment Trac environment], i.e. in the same `<Location>` block.
+This works whether you're using the [wiki:TracCgi CGI] or the [wiki:TracModPython mod_python] front-end. Put this directive next to where you set the path to the [wiki:TracEnvironment Trac environment], ie in the same `<Location>` block.
 For example (for CGI):
 {{{
+{{{#!apache
  <Location /trac>
    SetEnv TRAC_ENV /path/to/projenv
 …
 Or (for mod_python):
 {{{
+{{{#!apache
  <Location /trac>
    SetHandler mod_python
 …
 }}}
+ ''Note: !SetEnv requires the `mod_env` module which needs to be activated for Apache. In this case the !SetEnv directive can also be used in the `mod_python` Location block.''
+'''Note''': !SetEnv requires the `mod_env` module which needs to be activated for Apache. In this case the !SetEnv directive can also be used in the `mod_python` Location block.
 For [wiki:TracFastCgi FastCGI], you'll need to `-initial-env` option, or whatever is provided by your web server for setting environment variables.
+ ''Note: that if you already use -initial-env to set the project directory for either a single project or parent you will need to add an additional -initial-env directive to the !FastCgiConfig directive. I.e.
 {{{
+'''Note''': that if you already use -initial-env to set the project directory for either a single project or parent you will need to add an additional -initial-env directive to the !FastCgiConfig directive:
+{{{#!apache
 FastCgiConfig -initial-env TRAC_ENV=/var/lib/trac -initial-env PYTHON_EGG_CACHE=/var/lib/trac/plugin-cache
 }}}
 === About hook scripts ===
+=== About hook scripts
 If you've set up some subversion hook scripts that call the Trac engine, such as the post-commit hook script provided in the `/contrib` directory, make sure you define the `PYTHON_EGG_CACHE` environment variable within these scripts as well.
 == Troubleshooting ==
 === Is setuptools properly installed? ===
+== Troubleshooting
+=== Is setuptools properly installed?
 Try this from the command line:
 {{{
+{{{#!sh
 $ python -c "import pkg_resources"
 }}}
 …
 If you get '''no output''', setuptools '''is''' installed. Otherwise, you'll need to install it before plugins will work in Trac.
 === Did you get the correct version of the Python egg? ===
+=== Did you get the correct version of the Python egg?
 Python eggs have the Python version encoded in their filename. For example, `MyPlugin-1.0-py2.5.egg` is an egg for Python 2.5, and will '''not''' be loaded if you're running a different Python version (such as 2.4 or 2.6).
 …
 Also, verify that the egg file you downloaded is indeed a .zip archive. If you downloaded it from a Trac site, chances are you downloaded the HTML preview page instead.
 === Is the plugin enabled? ===
 If you install a plugin globally (i.e., ''not'' inside the `plugins` directory of the Trac project environment), you must explicitly enable it in [TracIni trac.ini]. Make sure that:
  * ...you actually added the necessary line(s) to the `[components]` section.
  * ...the package/module names are correct.
  * ...the value is "enabled", not "enable" or "Enable".
  * ...the section name is "components", not "component".
 === Check the permissions on the .egg file ===
+=== Is the plugin enabled?
+If you install a plugin globally, ie ''not'' inside the `plugins` directory of the Trac project environment, you must explicitly enable it in [TracIni trac.ini]. Make sure that:
+ * you actually added the necessary line(s) to the `[components]` section.
+ * the package/module names are correct.
+ * the value is "enabled", not "enable" or "Enable".
+ * the section name is "components", not "component".
+=== Check the permissions on the .egg file
 Trac must be able to read the .egg file.
 === Check the log files ===
+=== Check the log files
 Enable [wiki:TracLogging logging] and set the log level to `DEBUG`, then watch the log file for messages about loading plugins.
 === Verify you have proper permissions ===
+=== Verify you have proper permissions
 Some plugins require you have special permissions in order to use them. [trac:WebAdmin WebAdmin], for example, requires the user to have TRAC_ADMIN permissions for it to show up on the navigation bar.
 === Is the wrong version of the plugin loading? ===
+=== Is the wrong version of the plugin loading?
 If you put your plugins inside plugins directories, and certainly if you have more than one project, you need to make sure that the correct version of the plugin is loading. Here are some basic rules:
 …
  * Having more than one version listed inside Python site-packages is fine (i.e., installed with `setup.py install`) -- setuptools will make sure you get the version installed most recently. However, don't store more than one version inside a global or project plugins directory -- neither version number nor installed date will matter at all. There is no way to determine which one will be located first when Trac searches the directory for plugins.
 === If all of the above failed ===
+=== If all of the above failed
 Okay, so the logs don't mention plugins, the egg is readable, the Python version is correct, ''and'' the egg has been installed globally (and is enabled in trac.ini)... and it ''still'' doesn't work or give any error messages or any other indication as to why. Hop on the [trac:IrcChannel IrcChannel] and ask away!
 == Web-based plugin administration ==
 The WebAdmin plugin (part of the core since 0.11) offers limited support for plugin configuration through the web to users with `TRAC_ADMIN` permission:
+== Web-based plugin administration
+The [trac:WebAdmin] interface offers limited support for plugin configuration through the web to users with `TRAC_ADMIN` permission:
 * en/disabling installed plugins
 * installing plugins by uploading them as eggs
+You probably want to disable the second function for security reasons: in `trac.ini`, in the `[components]` section, add the line
 {{{
+If you wish to disable the second function for security reasons, add the following to the `[components]` section of trac.ini:
+{{{#!ini
 trac.admin.web_ui.PluginAdminPanel = disabled
 }}}