Changes between Version 1 and Version 2 of TracPlugins


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Timestamp:
08/11/15 13:16:01 (9 years ago)
Author:
trac
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  • TracPlugins

    v1 v2  
    1 = Trac Plugins =
     1= Trac plugins =
    22[[TracGuideToc]]
    33
    4 Since version 0.9, Trac supports plugins that extend the built-in functionality. The plugin functionality is based on the [http://trac.edgewall.org/wiki/TracDev/ComponentArchitecture component architecture].
    5 
    6 == Requirements ==
    7 
    8 To use egg based plugins in Trac, you need to have [http://peak.telecommunity.com/DevCenter/setuptools setuptools] (version 0.6) installed.
    9 
    10 Plugins can also consist of a single `.py` file dropped into either the environment or global `plugins` directory ''(since [milestone:0.10])''.
     4From 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.
     5
     6== Plugin discovery ==
     7
     8From 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.
     9
     10== Requirements for Trac eggs ==
     11
     12To use egg-based plugins in Trac, you need to have [http://peak.telecommunity.com/DevCenter/setuptools setuptools] (version 0.6) installed.
    1113
    1214To install `setuptools`, download the bootstrap module [http://peak.telecommunity.com/dist/ez_setup.py ez_setup.py] and execute it as follows:
     15
    1316{{{
    1417$ python ez_setup.py
    … …  
    1720If the `ez_setup.py` script fails to install the setuptools release, you can download it from [http://www.python.org/pypi/setuptools PyPI] and install it manually.
    1821
    19 == Installing a Trac Plugin ==
    20 
    21 === For a Single Project ===
    22 
    23 Plugins are packaged as [http://peak.telecommunity.com/DevCenter/PythonEggs Python eggs]. That means they are ZIP archives with the file extension `.egg`. If you have downloaded a source distribution of a plugin, you can run:
     22Plugins can also consist of a single `.py` file dropped directly into either the project's or the shared `plugins` directory.
     23
     24== Installing a Trac plugin ==
     25
     26=== For a single project ===
     27
     28Plugins are typically packaged as [http://peak.telecommunity.com/DevCenter/PythonEggs Python eggs]. That means they are .zip archives with the file extension `.egg`.
     29
     30If you have downloaded a source distribution of a plugin, and want to build the `.egg` file:
     31
     32 * Unpack the source. It should provide `setup.py`.
     33 * Run:
     34
    2435{{{
    2536$ python setup.py bdist_egg
    2637}}}
    27 to build the `.egg` file.
    28 
    29 Once you have the plugin archive, you need to 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.
    30 
    31 Note that the Python version that the egg is built with must
    32 match the Python version with which Trac is run.  If for
    33 instance you are running Trac under Python 2.3, but have
    34 upgraded your standalone Python to 2.4, the eggs won't be
    35 recognized.
    36 
    37 === For All Projects ===
     38
     39You should have a *.egg file. Examine the output of running python to find where this was created.
     40
     41Once 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).
     42
     43To uninstall a plugin installed this way, remove the egg from the `plugins` directory and restart the web server.
     44
     45Note: 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.
     46
     47Note 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.
     48
     49=== For all projects ===
    3850
    3951==== With an .egg file ====
    4052
    41 Some plugins (such as [http://trac.edgewall.org/wiki/WebAdmin WebAdmin]) are downloadable as a `.egg` file which can be installed with the `easy_install` program:
    42 {{{
    43 easy_install TracWebAdmin-0.1.1dev_r2765-py2.3.egg
    44 }}}
    45 
    46 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:\Python23\Scripts`) to their `PATH` environment variable (see [http://peak.telecommunity.com/DevCenter/EasyInstall#windows-notes easy_install Windows notes] for more information).
    47 
    48 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`:
    49 {{{
    50 easy_install --always-unzip TracWebAdmin-0.1.1dev_r2765-py2.3.egg
     53Some plugins (such as [trac:SpamFilter SpamFilter]) are downloadable as an `.egg` file that can be installed with the `easy_install` program:
     54{{{
     55easy_install TracSpamFilter
     56}}}
     57
     58If `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).
     59
     60If 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`:
     61{{{
     62easy_install --always-unzip TracSpamFilter-0.4.1_r10106-py2.6.egg
    5163}}}
    5264You should end up with a directory having the same name as the zipped egg (complete with `.egg` extension) and containing its uncompressed contents.
    5365
    54 Trac also searches for globally installed plugins under `$prefix/share/trac/plugins` ''(since 0.10)''.
     66Trac 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.
    5567
    5668==== From source ====
    5769
    58 If you downloaded the plugin's source from Subversion, or a source zip file you can install it using the included `setup.py`:
    59 {{{
    60 $ python setup.py install
     70`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:
     71{{{
     72easy_install http://svn.edgewall.com/repos/trac/plugins/0.12/spam-filter-captcha
    6173}}}
    6274
    6375==== Enabling the plugin ====
    64 Unlike plugins installed per-environment, you'll have to explicitly enable globally installed plugins via [wiki:TracIni trac.ini]. This is done in the `[components]` section of the configuration file, for example:
     76
     77Unlike 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.
     78
     79This is done in the `[components]` section of the configuration file. For example:
    6580{{{
    6681[components]
    67 webadmin.* = enabled
    68 }}}
    69 
    70 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 find out by looking at the source (look for a top-level directory that contains a file named `__init__.py`.)
    71 
    72 Note: After installing the plugin, you may need to restart Apache.
    73 
    74 == Setting up the Plugin Cache ==
    75 
    76 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 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.
    77 
    78 To do this from the Apache configuration, use the `SetEnv` directive as follows:
     82tracspamfilter.* = enabled
     83}}}
     84
     85The 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`).
     86
     87Note: After installing the plugin, you must restart your web server.
     88
     89==== Uninstalling ====
     90
     91`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:
     92
     93 1. Do `easy_install -m [plugin name]` to remove references from `$PYTHONLIB/site-packages/easy-install.pth` when the plugin installed by setuptools.
     94 1. Delete executables from `/usr/bin`, `/usr/local/bin`, or `C:\\Python*\Scripts`. To find what executables are involved, refer to the `[console-script]` section of `setup.py`.
     95 1. Delete the .egg file or folder from where it's installed (usually inside `$PYTHONLIB/site-packages/`).
     96 1. Restart the web server.
     97
     98If 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):
     99{{{
     100>>> import myplugin
     101>>> print myplugin.__file__
     102/opt/local/python24/lib/site-packages/myplugin-0.4.2-py2.4.egg/myplugin/__init__.pyc
     103}}}
     104
     105== Setting up the plugin cache ==
     106
     107Some 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.
     108
     109To do this from the Apache configuration, use the `SetEnv` directive:
    79110{{{
    80111SetEnv PYTHON_EGG_CACHE /path/to/dir
    81112}}}
    82113
    83 This works whether you are 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.
     114This 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.
    84115
    85116For example (for CGI):
    … …  
    91122}}}
    92123
    93 or (for mod_python):
     124Or (for mod_python):
    94125{{{
    95126 <Location /trac>
    … …  
    100131}}}
    101132
    102  ''Note: this requires the `mod_env` module''
    103 
    104 For [wiki:TracFastCgi FastCGI], you'll need to `-initial-env` option, or whatever is provided by your web server for setting environment variables.
     133 ''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.''
     134
     135For [wiki:TracFastCgi FastCGI], you'll need to `-initial-env` option, or whatever is provided by your web server for setting environment variables.
     136
     137 ''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.
     138
     139{{{
     140FastCgiConfig -initial-env TRAC_ENV=/var/lib/trac -initial-env PYTHON_EGG_CACHE=/var/lib/trac/plugin-cache
     141}}}
    105142
    106143=== About hook scripts ===
    107144
    108 If you have 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.
     145If 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.
    109146
    110147== Troubleshooting ==
    … …  
    121158=== Did you get the correct version of the Python egg? ===
    122159
    123 Python eggs have the Python version encoded in their filename. For example, `MyPlugin-1.0-py2.4.egg` is an egg for Python 2.4, and will '''not''' be loaded if you're running a different Python version (such as 2.3 or 2.5).
    124 
    125 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.
     160Python 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).
     161
     162Also, 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.
    126163
    127164=== Is the plugin enabled? ===
    128165
    129 If you install a plugin globally (i.e. ''not'' inside the `plugins` directory of the Trac project environment) you will have to explicitly enable it in [TracIni trac.ini]. Make sure that:
    130  * you actually added the necessary line(s) to the `[components]` section
    131  * the package/module names are correct
    132  * if you're reference a module (as opposed to a class), you've appended the necessary “.*”
    133  * the value is “enabled", not e.g. “enable”
    134 
    135 === Check the permissions on the egg file ===
    136 
    137 Trac must of course be able to read the file. Yeah, you knew that ;-)
     166If 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:
     167
     168 * ...you actually added the necessary line(s) to the `[components]` section.
     169 * ...the package/module names are correct.
     170 * ...the value is "enabled", not "enable" or "Enable".
     171 * ...the section name is "components", not "component".
     172
     173=== Check the permissions on the .egg file ===
     174
     175Trac must be able to read the .egg file.
    138176
    139177=== Check the log files ===
    140178
    141 Enable [TracLogging logging] in Trac, set the log level to `DEBUG` and then watch the log file for messages about loading plugins.
     179Enable [wiki:TracLogging logging] and set the log level to `DEBUG`, then watch the log file for messages about loading plugins.
     180
     181=== Verify you have proper permissions ===
     182
     183Some 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.
     184
     185=== Is the wrong version of the plugin loading? ===
     186
     187If 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:
     188
     189 * 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.
     190 * A globally-installed plugin (typically `setup.py install`) will override any version in the global or project plugins directories. A plugin from the global plugins directory will be located ''before'' any project plugins directory.
     191 * 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 uncertain 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.
     192 * 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.
     193
     194=== If all of the above failed ===
     195
     196Okay, 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!
     197
     198== Web-based plugin administration ==
     199
     200The WebAdmin plugin (part of the core since 0.11) offers limited support for plugin configuration through the web to users with `TRAC_ADMIN` permission:
     201
     202* en/disabling installed plugins
     203* installing plugins by uploading them as eggs
     204
     205You probably want to disable the second function for security reasons: in `trac.ini`, in the `[components]` section, add the line
     206{{{
     207trac.admin.web_ui.PluginAdminPanel = disabled
     208}}}
     209This disables the whole panel, so the first function will no longer be available either.
    142210
    143211----
    144 See also TracGuide, [http://trac.edgewall.org/wiki/PluginList plugin list], [http://trac.edgewall.org/wiki/TracDev/ComponentArchitecture component architecture]
     212See also TracGuide, [trac:PluginList plugin list], [trac:TracDev/ComponentArchitecture component architecture].