Changes between Initial Version and Version 1 of TracPlugins


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Timestamp:
06/01/24 09:28:38 (6 months ago)
Author:
trac
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  • TracPlugins

    v1 v1  
     1[[PageOutline(2-5,Contents,pullout)]]
     2
     3= Trac plugins
     4
     5Trac is extensible with [trac:PluginList plugins]. Plugin functionality is based on the [trac:TracDev/ComponentArchitecture component architecture], described in the [trac:TracDev/PluginDevelopment plugin development] page.
     6
     7== Plugin discovery
     8
     9A plugin is either a single .py file or a package (.egg or .whl). Trac looks for plugins in Python's `site-packages` directory, the [TracIni#GlobalConfiguration global shared] `plugins` directory and the [TracEnvironment project environment] `plugins` directory. Plugins installed to the project environment `plugins` directory are enabled, unless explicitly disabled in the `[components]` section of the `trac.ini` file. Plugins installed elsewhere must be explicitly enabled in the [TracIni#components-section "[components]"] section of the `trac.ini` file.
     10
     11== Installing a Trac plugin
     12
     13The instructions below are applicable to plugins installed as packages. Plugins implemented as a single `py` file should be downloaded and copied to the [TracEnvironment project environment] `plugins` directory or the [TracIni#GlobalConfiguration global shared] plugins directory.
     14
     15=== For a single project
     16
     17Packages built for a single project must use the egg format, as the wheel format (described below) is not supported by the setuptools loading mechanism. Build the `egg` file from the plugin source:
     18
     19* Checkout or download and unpack the source.
     20* Change to the directory containing `setup.py` and run:
     21 {{{#!sh
     22$ python setup.py bdist_egg
     23}}}
     24 The egg file will be created in the `dist` subdirectory.
     25* Copy the egg file to the `plugins` directory of the [TracEnvironment project environment].
     26
     27Make sure the web server has sufficient permissions to read the plugin egg and restart the web server. If you are running as a [TracStandalone "tracd" standalone server], restart tracd, i.e. kill the process and run again.
     28
     29Trac also searches for plugins installed in the [TracIni#GlobalConfiguration global shared] plugins directory. This is a convenient way to share the installation of plugins across several, but not all, environments.
     30
     31'''Note''': The minor version number of the Python used to build the egg ''must'' match the minor version number of the Python running Trac. For example, if you are running Trac with Python 2.6, but build the egg with Python 2.7, the egg won't be recognized.
     32
     33'''Note''': In a multi-project setup, a pool of Python interpreters 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 plugin in different projects of a multi-project setup. Install plugins for all projects (see below) and enable them as needed for each project.
     34
     35==== Uninstalling #UninstallEgg
     36
     37Remove the egg from the `plugins` directory and restart the web server.
     38
     39=== For all projects
     40
     41==== Using pip
     42
     43The modern Python package manager, `pip`, is included in Python 2.7.9 and later. In earlier versions of Python it can be installed through the package manager of your OS (e.g. `apt-get install python-pip`) or using [https://pip.pypa.io/en/latest/installing.html#install-pip get_pip.py].
     44
     45Using `pip`, the plugin will be installed in the [https://pythonwheels.com/ wheel format], which is the modern standard for Python and a replacement for the egg format.
     46
     47==== From PyPI
     48
     49Some plugins, such as [https://trac-hacks.org/wiki/TagsPlugin TracTags], can be installed directly from [https://pypi.org PyPI] using `pip`:
     50{{{#!sh
     51$ pip install TracTags
     52}}}
     53
     54The version can be specified, which can be useful if you don't want to install the latest:
     55{{{#!sh
     56$ pip install TracTags==1.2
     57}}}
     58
     59==== From source
     60
     61You can install directly from a source repository:
     62{{{#!sh
     63$ pip install svn+https://trac-hacks.org/svn/tagsplugin/trunk
     64}}}
     65
     66Replace the `svn+` prefix with `git+` if installing from a Git repository.
     67
     68Or from the path or URL of a tar.gz or zip archive:
     69{{{#!sh
     70$ pip install https://trac-hacks.org/browser/tagsplugin/trunk?format=zip
     71}}}
     72
     73Or checkout the source and provide `pip` a path to the source directory:
     74{{{#!sh
     75$ svn co https://trac-hacks.org/svn/tagsplugin/trunk tractags
     76$ pip install tractags
     77}}}
     78
     79==== Enabling the plugin
     80
     81Unlike plugins installed per environment, you have to explicitly enable globally installed plugins. This also applies to plugins installed in the shared plugins directory.
     82
     83This is done in the `[components]` section of the configuration file `trac.ini`. For example:
     84{{{#!ini
     85[components]
     86tractags.* = enabled
     87}}}
     88
     89The name of the option is the plugin package name. This should be specified in the documentation of the plugin, but can also be discovered by looking at the source: it is usually the top-level directory name containing a file named `__init__.py`.
     90
     91Plugins can also be enabled from the [#Web-basedpluginadministration administration] page.
     92
     93After installing the plugin, you must restart your web server.
     94
     95==== Upgrading the environment
     96
     97Some plugins require an environment upgrade. This will typically be necessary for plugins that implement `IEnvironmentSetupParticipant`. Common reasons for requiring an environment upgrade are to add tables to the database or add configuration parameters to `trac.ini`. A notification will be displayed when accessing Trac for the first time after installing a plugin and restarting the web server. To upgrade the environment, run the command:
     98
     99{{{#!sh
     100$ trac-admin /path/to/env upgrade
     101}}}
     102
     103A database backup will be made before upgrading the environment, unless the `--no-backup` option is specified. For more information, refer to the documentation output by `trac-admin /path/to/env help upgrade`.
     104
     105==== Redeploying static resources
     106
     107If you [TracInstall#MappingStaticResources mapped static resources] so they are served by the web server, and the plugin contains static resources, such as stylesheets, !JavaScript and image files, the resources will need to be deployed to the location on the filesystem that is served by the web server.
     108
     109Execute the `deploy` command, as is done during install and [TracUpgrade#a5.Refreshstaticresources upgrade]:
     110
     111{{{#!sh
     112$ trac-admin /path/to/env deploy /deploy/path
     113}}}
     114
     115After executing the command, you must restart your web server.
     116
     117{{{#!div style="border: 1pt dotted; margin: 1em"
     118**Note:** Some web browsers (IE, Opera) cache CSS and Javascript files, so you should instruct your users to manually erase the contents of their browser's cache. A forced refreshed (SHIFT + <F5>) should be enough.
     119{{{#!comment
     120Remove above note once #9936 is fixed.
     121}}}
     122}}}
     123
     124==== Uninstalling #UninstallWithPip
     125
     126Get a list of installed plugins:
     127{{{#!sh
     128$ pip list
     129Package    Version
     130---------- -------
     131Jinja2     2.10.1
     132MarkupSafe 1.1.1
     133pip        19.2.2
     134setuptools 41.2.0
     135Trac       1.4
     136TracTags   0.10
     137wheel      0.33.6
     138}}}
     139
     140Uninstall a plugin by specifying the package name:
     141{{{#!sh
     142$ pip uninstall TracTags
     143}}}
     144
     145== Web-based plugin administration
     146
     147The admin page offers limited support for plugin configuration to users with `TRAC_ADMIN` permission:
     148
     149* en/dis-abling installed plugins
     150* installing plugins by uploading them as eggs
     151
     152If you wish to disable the second function for security reasons, add the following to your `trac.ini` file:
     153{{{#!ini
     154[components]
     155trac.admin.web_ui.PluginAdminPanel = disabled
     156}}}
     157This disables the whole panel, so the first function will no longer be available.
     158
     159== Setting up the plugin cache
     160
     161Some plugins installed as eggs will need to be extracted by the Python egg's runtime (`pkg_resources`), so that their contents are actual files on the file system. The directory to 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.
     162
     163To do this from the Apache configuration, use the `SetEnv` directive:
     164{{{#!apache
     165SetEnv PYTHON_EGG_CACHE /path/to/dir
     166}}}
     167
     168This works whether you're using the [TracCgi CGI] or the [TracModPython mod_python] front-end. Put this directive next to where you set the path to the [TracEnvironment Trac environment], i.e. in the same `<Location>` block.
     169
     170For example for CGI:
     171{{{#!apache
     172 <Location /trac>
     173   SetEnv TRAC_ENV /path/to/projenv
     174   SetEnv PYTHON_EGG_CACHE /path/to/dir
     175 </Location>
     176}}}
     177
     178Or for mod_python:
     179{{{#!apache
     180 <Location /trac>
     181   SetHandler mod_python
     182   ...
     183   SetEnv PYTHON_EGG_CACHE /path/to/dir
     184 </Location>
     185}}}
     186
     187'''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.
     188
     189For [TracFastCgi FastCGI], you will need to `-initial-env` option, or whatever is provided by your web server for setting environment variables.
     190
     191'''Note''': 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:
     192
     193{{{#!apache
     194FastCgiConfig -initial-env TRAC_ENV=/var/lib/trac -initial-env PYTHON_EGG_CACHE=/var/lib/trac/plugin-cache
     195}}}
     196
     197=== About hook scripts
     198
     199If you have Subversion hook scripts that invoke Trac, 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.
     200
     201== Writing Trac Plugins
     202
     203You can write your own Trac plugin using the following resources:
     204* [trac:TracDev Developer documentation]
     205* [https://trac-hacks.org Examples on trac-hacks.org]
     206* [trac:browser:branches/1.4-stable/sample-plugins sample-plugins]
     207
     208== Troubleshooting
     209
     210=== Did you get the correct version of the Python egg?
     211
     212Python 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.
     213
     214Also, verify that the egg file you downloaded is indeed a .zip archive. If you downloaded it from a Trac site, you may have downloaded the HTML preview page instead.
     215
     216=== Is the plugin enabled?
     217
     218If 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:
     219
     220 * you added the necessary line(s) to the `[components]` section.
     221 * the package/module names are correct and do not contain typos.
     222 * the value is `enabled`, not `enable` or `Enable`.
     223 * the section name is `components`, not `component`.
     224
     225=== Check the permissions
     226
     227Trac must be able to read the .py file or package (.egg or .whl).
     228
     229=== Check the log files
     230
     231See [trac:TracTroubleshooting#ChecktheLogs].
     232
     233=== Verify you have the proper permissions
     234
     235Some plugins require you have special permissions. !TracTags, for example, requires `TAGS_VIEW` permissions for the //Tags// navigation item to be added.
     236
     237=== Is the wrong version of the plugin loading?
     238
     239If you put your plugins in one of the `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:
     240
     241* Only one version of the plugin can be loaded for each running Trac server, i.e. each Python process. The Python namespaces and module list will be shared, and it cannot handle duplicates. Whether a plugin is `enabled` or `disabled` makes no difference.
     242* A globally installed plugin will override any version in the global or project plugins directories. A plugin from the global plugins directory will be discovered ''before'' any project plugins directory.
     243* If your Trac server hosts more than one project (as with `TRAC_ENV_PARENT_DIR` setups), having two versions of a plugin in two different projects will give unpredictable results. Only one of them will load, and the one loaded will be shared by both projects. Trac will load the first plugin found, usually from the project that receives the first request.
     244* Having more than one version listed inside Python site-packages is fine, because 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 the version number nor the 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.
     245
     246=== If all of the above failed
     247
     248See TracSupport.
     249
     250----
     251See also TracGuide, TracIni.
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