Changes between Version 1 and Version 2 of TracPlugins


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Timestamp:
2011-11-17T12:29:42Z (13 years ago)
Author:
trac
Comment:

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  • TracPlugins

    v1 v2  
    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].
     4Trac is extensible with [trac:PluginList plugins] since version 0.9. The plugin functionality is based on the [trac:TracDev/ComponentArchitecture component architecture] with peculiarities described at [TracDev/PluginDevelopment plugin development] page.
    55
    6 == Requirements ==
     6== Plugin discovery ==
     7
     8From the user point of view a Plugin is either standalone .py file or an .egg package. Trac looks for Plugins in a global shared plugins directory (see [TracIni#GlobalConfiguration Global Configuration]) and in `plugins` directory of 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  ==
    711
    812To use egg based plugins in Trac, you need to have [http://peak.telecommunity.com/DevCenter/setuptools setuptools] (version 0.6) installed.
    … …  
    1519If 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.
    1620
    17 Plugins can also consist of a single `.py` file dropped into either the environment or global `plugins` directory ''(since [milestone:0.10])''.
     21Plugins can also consist of a single `.py` file dropped directly into the root of environment's or into shared `plugins` directory.
    1822
    1923== Installing a Trac Plugin ==
    … …  
    3236Then you will have a *.egg file. Examine the output of running python to find where this was created.
    3337
    34 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.
     38Once 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. Then, restart the web server (this requirement was not previously mentioned in this document, but in my tests it began working only after I did so).
     39
     40To uninstall a plugin installed this way, remove the egg from `plugins` directory and restart web server.
    3541
    3642Note that the Python version that the egg is built with must
    3743match the Python version with which Trac is run.  If for
    38 instance you are running Trac under Python 2.3, but have
    39 upgraded your standalone Python to 2.4, the eggs won't be
     44instance you are running Trac under Python 2.5, but have
     45upgraded your standalone Python to 2.6, the eggs won't be
    4046recognized.
     47
     48Note also that in a multi-project setup, a pool of Python interpreter instances will be dynamically allocated to projects based on need, and 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 the 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.
    4149
    4250=== For All Projects ===
    … …  
    4452==== With an .egg file ====
    4553
    46 Some plugins (such as [http://trac.edgewall.org/wiki/SpamFilter SpamFilter]) are downloadable as a `.egg` file which can be installed with the `easy_install` program:
     54Some plugins (such as [trac:SpamFilter SpamFilter]) are downloadable as a `.egg` file which can be installed with the `easy_install` program:
    4755{{{
    4856easy_install TracSpamFilter
    4957}}}
    5058
    51 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).
     59If `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).
    5260
    5361If 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`:
    5462{{{
    55 easy_install --always-unzip TracSpamFilter-0.2.1dev_r5943-py2.4.egg
     63easy_install --always-unzip TracSpamFilter-0.4.1_r10106-py2.6.egg
    5664}}}
    5765You should end up with a directory having the same name as the zipped egg (complete with `.egg` extension) and containing its uncompressed contents.
    5866
    59 Trac also searches for globally installed plugins under `$PREFIX/share/trac/plugins` ''(since 0.10)''.
     67Trac also searches for plugins installed in the shared plugins directory ''(since 0.10)'', see TracIni#GlobalConfiguration. This is a convenient way to share the installation of plugins across several but not all environments.
    6068
    6169==== From source ====
    … …  
    6371`easy_install` makes installing from source a snap. Just give it the URL to either a Subversion repository or a tarball/zip of the source:
    6472{{{
    65 easy_install http://svn.edgewall.com/repos/trac/sandbox/spam-filter
     73easy_install http://svn.edgewall.com/repos/trac/plugins/0.12/spam-filter-captcha
    6674}}}
    6775
    6876==== Enabling the plugin ====
    69 Unlike plugins installed per-environment, you'll have to explicitly enable globally installed plugins via [wiki:TracIni trac.ini]. This is done in the `[components]` section of the configuration file, for example:
     77Unlike plugins installed per-environment, you'll have to explicitly enable globally installed plugins via [wiki:TracIni trac.ini]. This also applies to plugins installed in shared plugins directory, i.e. the path specified in the `[inherit] plugins_dir` configuration option.
     78
     79This is done in the `[components]` section of the configuration file, for example:
    7080{{{
    7181[components]
    … …  
    7787Note: After installing the plugin, you need to restart your web server.
    7888
     89==== Uninstalling ====
     90
     91`easy_install` or `python setup.py` does not have an uninstall feature. Hower, it is usually quite trivial to remove a globally installed egg and reference:
     92 1. Do `easy_install -m [plugin name]` to remove references from `$PYTHONLIB/site-packages/easy-install.pth` when the plugin installed by setuptools.
     93 1. Delete executables from `/usr/bin`, `/usr/local/bin` or `C:\\Python*\Scripts`. For search what executables are there, you may refer to `[console-script]` section of `setup.py`.
     94 1. Delete the .egg file or folder from where it is installed, usually inside `$PYTHONLIB/site-packages/`.
     95 1. Restart web server.
     96
     97If you are uncertain about the location of the egg, here is a small tip to help locate an egg (or any package) - replace `myplugin` with whatever namespace the plugin uses (as used when enabling the plugin):
     98{{{
     99>>> import myplugin
     100>>> print myplugin.__file__
     101/opt/local/python24/lib/site-packages/myplugin-0.4.2-py2.4.egg/myplugin/__init__.pyc
     102}}}
     103
    79104== Setting up the Plugin Cache ==
    80105
    81 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.
     106Some 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.
    82107
    83108To do this from the Apache configuration, use the `SetEnv` directive as follows:
    … …  
    105130}}}
    106131
    107  ''Note: this requires the `mod_env` module''
     132 ''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.''
    108133
    109134For [wiki:TracFastCgi FastCGI], you'll need to `-initial-env` option, or whatever is provided by your web server for setting environment variables.
    110135
    111  ''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 atleast one environment variable inside trac.fcgi as expressed in the example on [wiki:TracFastCgi TracFastCgi].
     136 ''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.
     137
     138{{{
     139FastCgiConfig -initial-env TRAC_ENV=/var/lib/trac -initial-env PYTHON_EGG_CACHE=/var/lib/trac/plugin-cache
     140}}}
    112141
    113142=== About hook scripts ===
    … …  
    128157=== Did you get the correct version of the Python egg? ===
    129158
    130 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).
     159Python 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).
    131160
    132161Also, 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.
    133162
    134163=== Is the plugin enabled? ===
     164
    135165
    136166If 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:
    … …  
    149179=== Verify you have proper permissions ===
    150180
    151 Some plugins require you have special permissions in order to use them. WebAdmin, for example, requires the user to have TRAC_ADMIN permissions for it to show up on the navigation bar.
     181Some 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.
    152182
    153183=== Is the wrong version of the plugin loading? ===
    154184
    155 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 som basic rules:
     185If 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:
    156186 * Only one version of the plugin can be loaded for each running Trac server (ie. 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.
    157187 * A globally installed plugin (typically `setup.py install`) will override any version in global or project plugins directories. A plugin from the global plugins directory will be located before any project plugins directory.
    … …  
    161191=== If all of the above failed ===
    162192
    163 OK, 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 the trac.ini) and it still doesn't work or give any error messages or any other indication as to why? Hop on the IrcChannel and ask away.
     193OK, 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 the 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.
    164194
    165195----
    166 See also TracGuide, [http://trac.edgewall.org/wiki/PluginList plugin list], [http://trac.edgewall.org/wiki/TracDev/ComponentArchitecture component architecture]
     196See also TracGuide, [trac:PluginList plugin list], [trac:TracDev/ComponentArchitecture component architecture]