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Changes between Version 1 and Version 2 of TracPlugins


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Timestamp:
10/09/08 11:57:26 (6 years ago)
Author:
trac
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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://projects.edgewall.com/trac/wiki/TracDev/ComponentArchitecture component architecture].
     4Since version 0.9, Trac supports [PluginList plugins] that extend the built-in functionality. The plugin functionality is based on the [trac:TracDev/ComponentArchitecture component architecture].
    55
    66== Requirements ==
    77
    8 To use plugins in Trac, you need to have [http://peak.telecommunity.com/DevCenter/setuptools setuptools] (version 0.6) installed.
     8To use egg based plugins in Trac, you need to have [http://peak.telecommunity.com/DevCenter/setuptools setuptools] (version 0.6) installed.
    99
    1010To install `setuptools`, download the bootstrap module [http://peak.telecommunity.com/dist/ez_setup.py ez_setup.py] and execute it as follows:
     
    1515If 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.
    1616
     17Plugins can also consist of a single `.py` file dropped into either the environment or global `plugins` directory ''(since [milestone:0.10])''. See TracIni#GlobalConfiguration .
     18
    1719== Installing a Trac Plugin ==
    1820
    1921=== For a Single Project ===
    2022
    21 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:
     23Plugins are packaged as [http://peak.telecommunity.com/DevCenter/PythonEggs Python eggs]. That means they are ZIP archives with the file extension `.egg`.
     24
     25If you have downloaded a source distribution of a plugin, and want to build the `.egg` file, follow this instruction:
     26 * Unpack the source. It should provide a setup.py.
     27 * Run:
    2228{{{
    2329$ python setup.py bdist_egg
    2430}}}
    25 to build the `.egg` file.
     31
     32Then you will have a *.egg file. Examine the output of running python to find where this was created.
    2633
    2734Once 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.
    2835
     36To uninstall a plugin installed this way, remove the egg from `plugins` directory and restart web server.
     37
     38Note that the Python version that the egg is built with must
     39match the Python version with which Trac is run.  If for
     40instance you are running Trac under Python 2.3, but have
     41upgraded your standalone Python to 2.4, the eggs won't be
     42recognized.
     43
     44Note 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.
     45
    2946=== For All Projects ===
    3047
    31 Plugins that you want to use in all your projects (such as [http://projects.edgewall.com/trac/wiki/WebAdmin WebAdmin]) can be installed globally by running:
     48==== With an .egg file ====
     49
     50Some plugins (such as [trac:SpamFilter SpamFilter]) are downloadable as a `.egg` file which can be installed with the `easy_install` program:
    3251{{{
    33 $ python setup.py install
     52easy_install TracSpamFilter
    3453}}}
    3554
    36 Alternatively, you can just drop the `.egg` file in the Python `site-packages` directory.
     55If `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).
    3756
     57If 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`:
     58{{{
     59easy_install --always-unzip TracSpamFilter-0.2.1dev_r5943-py2.4.egg
     60}}}
     61You should end up with a directory having the same name as the zipped egg (complete with `.egg` extension) and containing its uncompressed contents.
     62
     63Trac also searches for globally installed plugins ''(since 0.10)'', see TracIni#GlobalConfiguration.
     64
     65==== From source ====
     66
     67`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:
     68{{{
     69easy_install http://svn.edgewall.com/repos/trac/sandbox/spam-filter
     70}}}
     71
     72==== Enabling the plugin ====
    3873Unlike 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:
    3974{{{
    4075[components]
    41 webadmin.* = enabled
     76tracspamfilter.* = enabled
    4277}}}
    4378
    44 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`.)
     79The 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`.)
     80
     81Note: After installing the plugin, you need to restart your web server.
     82
     83==== Uninstalling ====
     84
     85`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:
     86 1. Do `easy_install -m [plugin name]` to remove references from `$PYTHONLIB/site-packages/easy-install.pth` when the plugin installed by setuptools.
     87 1. Delete executables from `/usr/bin`, `/usr/local/bin` or `C:\\Python*\Scripts`. For search what executables are there, you may refer to `[console-script]` section of `setup.py`.
     88 1. Delete the .egg file or folder from where it is installed, usually inside `$PYTHONLIB/site-packages/`.
     89 1. Restart web server.
     90
     91If 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):
     92{{{
     93>>> import myplugin
     94>>> print myplugin.__file__
     95/opt/local/python24/lib/site-packages/myplugin-0.4.2-py2.4.egg/myplugin/__init__.pyc
     96}}}
    4597
    4698== Setting up the Plugin Cache ==
     
    53105}}}
    54106
    55 This works whether your 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.
     107This 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.
    56108
    57109For example (for CGI):
     
    72124}}}
    73125
    74 For [wiki:TracFastCgi FastCGI], you'll need to `-initial-env` option, or whatever is provided by your web server for setting environment variables.
     126 ''Note: this requires the `mod_env` module''
     127
     128For [wiki:TracFastCgi FastCGI], you'll need to `-initial-env` option, or whatever is provided by your web server for setting environment variables.
     129
     130 ''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].
     131
     132=== About hook scripts ===
     133
     134If 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.
     135
     136== Troubleshooting ==
     137
     138=== Is setuptools properly installed? ===
     139
     140Try this from the command line:
     141{{{
     142$ python -c "import pkg_resources"
     143}}}
     144
     145If you get '''no output''', setuptools '''is''' installed. Otherwise, you'll need to install it before plugins will work in Trac.
     146
     147=== Did you get the correct version of the Python egg? ===
     148
     149Python 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).
     150
     151Also, 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.
     152
     153=== Is the plugin enabled? ===
     154
     155If 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:
     156 * you actually added the necessary line(s) to the `[components]` section
     157 * the package/module names are correct
     158 * the value is “enabled", not e.g. “enable”
     159
     160=== Check the permissions on the egg file ===
     161
     162Trac must be able to read the file.
     163
     164=== Check the log files ===
     165
     166Enable [wiki:TracLogging logging] and set the log level to `DEBUG`, then watch the log file for messages about loading plugins.
     167
     168=== Verify you have proper permissions ===
     169
     170Some 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.
     171
     172=== Is the wrong version of the plugin loading? ===
     173
     174If 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:
     175 * 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.
     176 * 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.
     177 * If your Trac server hosts more than one project (as with `TRAC_ENV_PARENT_DIR` setups), then 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 found - basically from the project that receives the first request.
     178 * Having more than one version listed inside Python site-packages is fine (ie. 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.
     179
     180=== If all of the above failed ===
     181
     182OK, 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.
    75183
    76184----
    77 See also TracGuide, [http://projects.edgewall.com/trac/wiki/PluginList plugin list], [http://projects.edgewall.com/trac/wiki/TracDev/ComponentArchitecture component architecture]
     185See also TracGuide, [trac:PluginList plugin list], [trac:TracDev/ComponentArchitecture component architecture]