1 | | = Trac plugins = |
2 | | [[TracGuideToc]] |
3 | | |
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 | | |
6 | | == Plugin discovery == |
7 | | |
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. |
| 1 | [[PageOutline(2-5,Contents,pullout)]] |
| 2 | |
| 3 | = Trac plugins |
| 4 | |
| 5 | Trac is extensible with [trac:PluginList plugins]. Plugin functionality is based on the [trac:TracDev/ComponentArchitecture component architecture], with special cases described in the [trac:TracDev/PluginDevelopment plugin development] page. |
| 6 | |
| 7 | == Plugin discovery |
| 8 | |
| 9 | From the user's point of view, a plugin is either a standalone .py file or an .egg package. Trac looks for plugins in Python's `site-packages` directory, the [TracIni#GlobalConfiguration global shared] `plugins` directory and the [TracEnvironment project environment] `plugins` directory. Components defined in globally-installed plugins must be explicitly enabled in the [[TracIni#components-section| [components] ]] section of the `trac.ini` file. Components defined in the `plugins` directory of the project environment are enabled, unless explicitly disabled in the `[components]` section of the `trac.ini` file. |
| 10 | |
| 11 | == Requirements for Trac eggs #Requirements |
| 12 | |
| 13 | To use egg-based plugins in Trac, you need to have [http://peak.telecommunity.com/DevCenter/setuptools setuptools] (version >= 0.6) installed. |
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 === |
50 | | |
51 | | ==== With an .egg file ==== |
52 | | |
53 | | Some plugins (such as [trac:SpamFilter SpamFilter]) are downloadable as an `.egg` file that can be installed with the `easy_install` program: |
54 | | {{{ |
55 | | easy_install TracSpamFilter |
56 | | }}} |
57 | | |
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`: |
61 | | {{{ |
62 | | easy_install --always-unzip TracSpamFilter-0.4.1_r10106-py2.6.egg |
63 | | }}} |
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. |
65 | | |
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. |
67 | | |
68 | | ==== From source ==== |
| 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 are running Trac under Python 2.6, but have upgraded your standalone Python to 2.7, the eggs won't be recognized. |
| 46 | |
| 47 | '''Note''': 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 |
| 50 | |
| 51 | ==== With an .egg file |
| 52 | |
| 53 | Some plugins, such as [https://trac-hacks.org/wiki/TagsPlugin TracTags], are downloadable as an `.egg` file that can be installed with `easy_install` or `pip`: |
| 54 | {{{#!sh |
| 55 | $ easy_install TracTags |
| 56 | $ pip install TracTags |
| 57 | }}} |
| 58 | |
| 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:\Python27\Scripts`) to their `PATH` environment variable, or use the full path to `easy_install` (for example, `C:\Python27\Scripts\easy_install.py`). See [http://peak.telecommunity.com/DevCenter/EasyInstall#windows-notes easy_install Windows notes] for more information. |
| 60 | |
| 61 | `pip` is included in Python 2.7.9. In earlier versions of Python it can be installed through the package manager of your OS (e.g. `apt-get install python-pip`) or using the [https://pip.pypa.io/en/latest/installing.html#install-pip get_pip.py]. |
| 62 | |
| 63 | If Trac reports permission errors after installing a zipped egg, and you would rather not bother providing an 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`: |
| 64 | {{{#!sh |
| 65 | $ easy_install --always-unzip TracTags |
| 66 | }}} |
| 67 | You should end up with a directory having the same name as the zipped egg, complete with `.egg` extension, and containing its uncompressed contents. |
| 68 | |
| 69 | Trac also searches for plugins installed in the shared plugins directory, see TracIni#GlobalConfiguration. This is a convenient way to share the installation of plugins across several, but not all, environments. |
| 70 | |
| 71 | ==== From source |
82 | | tracspamfilter.* = enabled |
83 | | }}} |
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 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: |
| 85 | tractags.* = enabled |
| 86 | }}} |
| 87 | |
| 88 | 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`. |
| 89 | |
| 90 | After installing the plugin, you must restart your web server. |
| 91 | |
| 92 | ==== Upgrading the environment |
| 93 | |
| 94 | Some plugins may require an environment upgrade. This will typically be necessary for plugins that implement `IEnvironmentSetupParticipant`. Common reasons for requiring an environment upgrade are to add tables to the database or add configuration parameters to trac.ini. A notification will be displayed when accessing Trac for the first time after installing a plugin and restarting the web server. To upgrade the environment, run the command: |
| 95 | |
| 96 | {{{#!sh |
| 97 | $ trac-admin /path/to/env upgrade |
| 98 | }}} |
| 99 | |
| 100 | A database backup will be made before upgrading the environment, unless the `--no-backup` option is specified. For more information, refer to the documentation output by `trac-admin /path/to/env help upgrade`. |
| 101 | |
| 102 | ==== Uninstalling |
| 103 | |
| 104 | Neither `easy_install` nor `python setup.py` have an uninstall feature. However, it is usually trivial to remove a globally installed egg and reference: |
143 | | === About hook scripts === |
144 | | |
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. |
146 | | |
147 | | == Troubleshooting == |
148 | | |
149 | | === Is setuptools properly installed? === |
150 | | |
151 | | Try this from the command line: |
152 | | {{{ |
153 | | $ python -c "import pkg_resources" |
154 | | }}} |
155 | | |
156 | | If you get '''no output''', setuptools '''is''' installed. Otherwise, you'll need to install it before plugins will work in Trac. |
157 | | |
158 | | === Did you get the correct version of the Python egg? === |
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). |
161 | | |
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. |
163 | | |
164 | | === Is the plugin enabled? === |
165 | | |
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 | | * ...the section name is "components", not "component". |
172 | | |
173 | | === Check the permissions on the .egg file === |
174 | | |
175 | | Trac must be able to read the .egg file. |
176 | | |
177 | | === Check the log files === |
178 | | |
179 | | Enable [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 | | |
183 | | Some 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 | | |
187 | | 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: |
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 | | |
196 | | 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! |
197 | | |
198 | | == Web-based plugin administration == |
199 | | |
200 | | 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: |
| 156 | === About hook scripts |
| 157 | |
| 158 | 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. |
| 159 | |
| 160 | == Web-based plugin administration |
| 161 | |
| 162 | The [trac:WebAdmin] interface offers limited support for plugin configuration through the web to users with `TRAC_ADMIN` permission: |
| 173 | |
| 174 | == Troubleshooting |
| 175 | |
| 176 | === Is setuptools properly installed? |
| 177 | |
| 178 | Try this from the command line: |
| 179 | {{{#!sh |
| 180 | $ python -c "import pkg_resources" |
| 181 | }}} |
| 182 | |
| 183 | If you get '''no output''', setuptools '''is''' installed. Otherwise, you'll need to install it before plugins will work in Trac. |
| 184 | |
| 185 | === Did you get the correct version of the Python egg? |
| 186 | |
| 187 | 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). |
| 188 | |
| 189 | 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. |
| 190 | |
| 191 | === Is the plugin enabled? |
| 192 | |
| 193 | If you install a plugin globally, ie ''not'' inside the `plugins` directory of the Trac project environment, you must explicitly enable it in [TracIni trac.ini]. Make sure that: |
| 194 | |
| 195 | * you actually added the necessary line(s) to the `[components]` section. |
| 196 | * the package/module names are correct and do not contain typos. |
| 197 | * the value is "enabled", not "enable" or "Enable". |
| 198 | * the section name is "components", not "component". |
| 199 | |
| 200 | === Check the permissions on the .egg file |
| 201 | |
| 202 | Trac must be able to read the .egg file. |
| 203 | |
| 204 | === Check the log files |
| 205 | |
| 206 | Enable [wiki:TracLogging logging] and set the log level to `DEBUG`, then watch the log file for messages about loading plugins. |
| 207 | |
| 208 | === Verify you have the proper permissions |
| 209 | |
| 210 | Some 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. |
| 211 | |
| 212 | === Is the wrong version of the plugin loading? |
| 213 | |
| 214 | 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: |
| 215 | |
| 216 | * 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. |
| 217 | * 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. |
| 218 | * 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 unpredicatable 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. |
| 219 | * Having more than one version listed inside Python site-packages is fine, ie installed with `setup.py install`, because 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 the version number nor the 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. |
| 220 | |
| 221 | === If all of the above failed |
| 222 | |
| 223 | 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! |