Changes between Version 3 and Version 4 of TracPlugins
- Timestamp:
- 22/08/2013 01:03:16 (11 years ago)
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TracPlugins
v3 v4 1 = Trac Plugins =1 = Trac plugins = 2 2 [[TracGuideToc]] 3 3 4 Trac 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.4 From 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 5 6 6 == Plugin discovery == 7 7 8 From 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 globallyinstalled plugins should be explicitly enabled in the [[TracIni#components-section| [components] ]] section of the trac.ini file.9 10 == Requirements for Trac eggs 11 12 To use egg 8 From 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 12 To use egg-based plugins in Trac, you need to have [http://peak.telecommunity.com/DevCenter/setuptools setuptools] (version 0.6) installed. 13 13 14 14 To install `setuptools`, download the bootstrap module [http://peak.telecommunity.com/dist/ez_setup.py ez_setup.py] and execute it as follows: 15 15 16 {{{ 16 17 $ python ez_setup.py … … 19 20 If 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. 20 21 21 Plugins can also consist of a single `.py` file dropped directly into the root of environment's or into shared `plugins` directory. 22 23 == Installing a Trac Plugin == 24 25 === For a Single Project === 26 27 Plugins are packaged as [http://peak.telecommunity.com/DevCenter/PythonEggs Python eggs]. That means they are ZIP archives with the file extension `.egg`. 28 29 If you have downloaded a source distribution of a plugin, and want to build the `.egg` file, follow this instruction: 30 * Unpack the source. It should provide a setup.py. 22 Plugins 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 28 Plugins are typically packaged as [http://peak.telecommunity.com/DevCenter/PythonEggs Python eggs]. That means they are .zip archives with the file extension `.egg`. 29 30 If 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`. 31 33 * Run: 34 32 35 {{{ 33 36 $ python setup.py bdist_egg 34 37 }}} 35 38 36 Then you will have a *.egg file. Examine the output of running python to find where this was created. 37 38 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. 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 40 To uninstall a plugin installed this way, remove the egg from `plugins` directory and restart web server. 41 42 Note that the Python version that the egg is built with must 43 match the Python version with which Trac is run. If for 44 instance you are running Trac under Python 2.5, but have 45 upgraded your standalone Python to 2.6, the eggs won't be 46 recognized. 47 48 Note 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. 49 50 === For All Projects === 39 You should have a *.egg file. Examine the output of running python to find where this was created. 40 41 Once 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 43 To uninstall a plugin installed this way, remove the egg from the `plugins` directory and restart the web server. 44 45 Note: 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 47 Note 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 === 51 50 52 51 ==== With an .egg file ==== 53 52 54 Some plugins (such as [trac:SpamFilter SpamFilter]) are downloadable as a `.egg` file whichcan be installed with the `easy_install` program:53 Some plugins (such as [trac:SpamFilter SpamFilter]) are downloadable as an `.egg` file that can be installed with the `easy_install` program: 55 54 {{{ 56 55 easy_install TracSpamFilter 57 56 }}} 58 57 59 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:\Python24\Scripts`) to their `PATH` environment variable (see [http://peak.telecommunity.com/DevCenter/EasyInstall#windows-notes easy_install Windows notes] for more information).60 61 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`:58 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:\Python24\Scripts`) to their `PATH` environment variable (see [http://peak.telecommunity.com/DevCenter/EasyInstall#windows-notes easy_install Windows notes] for more information). 59 60 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`: 62 61 {{{ 63 62 easy_install --always-unzip TracSpamFilter-0.4.1_r10106-py2.6.egg … … 65 64 You should end up with a directory having the same name as the zipped egg (complete with `.egg` extension) and containing its uncompressed contents. 66 65 67 Trac 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 allenvironments.66 Trac 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. 68 67 69 68 ==== From source ==== … … 75 74 76 75 ==== Enabling the plugin ==== 77 Unlike 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 79 This is done in the `[components]` section of the configuration file, for example: 76 77 Unlike 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 79 This is done in the `[components]` section of the configuration file. For example: 80 80 {{{ 81 81 [components] … … 83 83 }}} 84 84 85 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 discovered by looking at the source (look for a top-level directory that contains a file named `__init__.py` .)86 87 Note: After installing the plugin, you need torestart your web server.85 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 discovered by looking at the source (look for a top-level directory that contains a file named `__init__.py`). 86 87 Note: After installing the plugin, you must restart your web server. 88 88 89 89 ==== Uninstalling ==== 90 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: 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 92 93 1. Do `easy_install -m [plugin name]` to remove references from `$PYTHONLIB/site-packages/easy-install.pth` when the plugin installed by setuptools. 93 1. Delete executables from `/usr/bin`, `/usr/local/bin` or `C:\\Python*\Scripts`. For search what executables are there, you may refer to`[console-script]` section of `setup.py`.94 1. Delete the .egg file or folder from where it is installed, usually inside `$PYTHONLIB/site-packages/`.95 1. Restart web server.96 97 If 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):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 98 If 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): 98 99 {{{ 99 100 >>> import myplugin … … 102 103 }}} 103 104 104 == Setting up the Plugin Cache ==105 106 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 '.python-eggs' in the home directory of the current user, which may or may not be a problem. You can howeveroverride the default location using the `PYTHON_EGG_CACHE` environment variable.107 108 To do this from the Apache configuration, use the `SetEnv` directive as follows:105 == Setting up the plugin cache == 106 107 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 `.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. 108 109 To do this from the Apache configuration, use the `SetEnv` directive: 109 110 {{{ 110 111 SetEnv PYTHON_EGG_CACHE /path/to/dir 111 112 }}} 112 113 113 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.114 This 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. 114 115 115 116 For example (for CGI): … … 121 122 }}} 122 123 123 or (for mod_python):124 Or (for mod_python): 124 125 {{{ 125 126 <Location /trac> … … 142 143 === About hook scripts === 143 144 144 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.145 If 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. 145 146 146 147 == Troubleshooting == … … 159 160 Python 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). 160 161 161 Also, verify that the egg file you downloaded is indeed a ZIParchive. If you downloaded it from a Trac site, chances are you downloaded the HTML preview page instead.162 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. 162 163 163 164 === Is the plugin enabled? === 164 165 165 166 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: 167 * you actually added the necessary line(s) to the `[components]` section168 * the package/module names are correct169 * the value is “enabled", not e.g. “enable”170 171 === Check the permissions on the egg file ===172 173 Trac must be able to read the file.166 If 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". 171 172 === Check the permissions on the .egg file === 173 174 Trac must be able to read the .egg file. 174 175 175 176 === Check the log files === … … 184 185 185 186 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 some basic rules: 186 * 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. 187 * 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. 188 * 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. 189 * 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. 187 188 * 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. 189 * 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. 190 * 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. 191 * 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. 190 192 191 193 === If all of the above failed === 192 194 193 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 [trac:IrcChannel IrcChannel] and ask away. 195 Okay, 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! 196 197 == Web-based plugin administration == 198 199 The WebAdmin plugin (part of the core since 0.11) offers limited support for plugin configuration through the web to users with `TRAC_ADMIN` permission: 200 201 * en/disabling installed plugins 202 * installing plugins by uploading them as eggs 203 204 You probably want to disable the second function for security reasons: in `trac.ini`, in the `[components]` section, add the line 205 {{{ 206 trac.admin.web_ui.PluginAdminPanel = disabled 207 }}} 208 This disables the whole panel, so the first function will no longer be available either. 194 209 195 210 ---- 196 See also TracGuide, [trac:PluginList plugin list], [trac:TracDev/ComponentArchitecture component architecture] 211 See also TracGuide, [trac:PluginList plugin list], [trac:TracDev/ComponentArchitecture component architecture].
