Changes between Version 2 and Version 3 of TracPlugins


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Timestamp:
11/06/10 11:32:43 (4 years ago)
Author:
trac
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  • TracPlugins

    v2 v3  
    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]. 
     4Since version 0.9, Trac supports [trac:PluginList plugins] that extend the built-in functionality. The plugin functionality is based on the [trac:TracDev/ComponentArchitecture component architecture]. 
    55 
    66== Requirements == 
    77 
    88To 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])''. 
    119 
    1210To install `setuptools`, download the bootstrap module [http://peak.telecommunity.com/dist/ez_setup.py ez_setup.py] and execute it as follows: 
     
    1715If 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. 
    1816 
     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 
    1919== Installing a Trac Plugin == 
    2020 
    2121=== For a Single Project === 
    2222 
    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: 
     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: 
    2428{{{ 
    2529$ python setup.py bdist_egg 
    2630}}} 
    27 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. 
    2833 
    2934Once 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. 
     35 
     36To uninstall a plugin installed this way, remove the egg from `plugins` directory and restart web server. 
    3037 
    3138Note that the Python version that the egg is built with must 
     
    3542recognized. 
    3643 
     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 
    3746=== For All Projects === 
    3847 
    3948==== With an .egg file ==== 
    4049 
    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: 
     50Some plugins (such as [trac:SpamFilter SpamFilter]) are downloadable as a `.egg` file which can be installed with the `easy_install` program: 
    4251{{{ 
    43 easy_install TracWebAdmin-0.1.1dev_r2765-py2.3.egg 
     52easy_install TracSpamFilter 
    4453}}} 
    4554 
     
    4857If 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`: 
    4958{{{ 
    50 easy_install --always-unzip TracWebAdmin-0.1.1dev_r2765-py2.3.egg 
     59easy_install --always-unzip TracSpamFilter-0.2.1dev_r5943-py2.4.egg 
    5160}}} 
    5261You should end up with a directory having the same name as the zipped egg (complete with `.egg` extension) and containing its uncompressed contents. 
    5362 
    54 Trac also searches for globally installed plugins under `$prefix/share/trac/plugins` ''(since 0.10)''. 
     63Trac also searches for globally installed plugins ''(since 0.10)'', see TracIni#GlobalConfiguration. 
    5564 
    5665==== From source ==== 
    5766 
    58 If you downloaded the plugin's source from Subversion, or a source zip file you can install it using the included `setup.py`: 
     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: 
    5968{{{ 
    60 $ python setup.py install 
     69easy_install http://svn.edgewall.com/repos/trac/sandbox/spam-filter 
    6170}}} 
    6271 
    6372==== 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: 
     73Unlike 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 path specified in the `[inherit] plugins_dir` configuration option. This is done in the `[components]` section of the configuration file, for example: 
    6574{{{ 
    6675[components] 
    67 webadmin.* = enabled 
     76tracspamfilter.* = enabled 
    6877}}} 
    6978 
    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`.) 
     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`.) 
    7180 
    72 Note: After installing the plugin, you may need to restart Apache. 
     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}}} 
    7397 
    7498== Setting up the Plugin Cache == 
    7599 
    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. 
     100Some 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. 
    77101 
    78102To do this from the Apache configuration, use the `SetEnv` directive as follows: 
     
    100124}}} 
    101125 
    102  ''Note: this requires the `mod_env` module'' 
     126 ''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.'' 
    103127 
    104 For [wiki:TracFastCgi FastCGI], you'll need to `-initial-env` option, or whatever is provided by your web server for setting environment variables. 
     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 an additional -initial-env directive to the !FastCgiConfig directive. I.e. 
     131 
     132{{{ 
     133FastCgiConfig -initial-env TRAC_ENV=/var/lib/trac -initial-env PYTHON_EGG_CACHE=/var/lib/trac/plugin-cache 
     134}}} 
    105135 
    106136=== About hook scripts === 
     
    127157=== Is the plugin enabled? === 
    128158 
     159 
    129160If 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: 
    130161 * you actually added the necessary line(s) to the `[components]` section 
    131162 * the package/module names are correct 
    132  * if you're reference a module (as opposed to a class), you've appended the necessary “.*” 
    133163 * the value is “enabled", not e.g. “enable” 
    134164 
    135165=== Check the permissions on the egg file === 
    136166 
    137 Trac must of course be able to read the file. Yeah, you knew that ;-) 
     167Trac must be able to read the file.  
    138168 
    139169=== Check the log files === 
    140170 
    141 Enable [TracLogging logging] in Trac, set the log level to `DEBUG` and then watch the log file for messages about loading plugins. 
     171Enable [wiki:TracLogging logging] and set the log level to `DEBUG`, then watch the log file for messages about loading plugins. 
     172 
     173=== Verify you have proper permissions === 
     174 
     175Some 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. 
     176 
     177=== Is the wrong version of the plugin loading? === 
     178 
     179If 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: 
     180 * 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. 
     181 * 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. 
     182 * 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. 
     183 * 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. 
     184 
     185=== If all of the above failed === 
     186 
     187OK, 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. 
    142188 
    143189---- 
    144 See also TracGuide, [http://trac.edgewall.org/wiki/PluginList plugin list], [http://trac.edgewall.org/wiki/TracDev/ComponentArchitecture component architecture] 
     190See also TracGuide, [trac:PluginList plugin list], [trac:TracDev/ComponentArchitecture component architecture]