Changes between Version 5 and Version 6 of TracPlugins


Ignore:
Timestamp:
Jan 12, 2016, 11:21:52 PM (3 years ago)
Author:
trac
Comment:

--

Legend:

Unmodified
Added
Removed
Modified
  • TracPlugins

    v5 v6  
    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.
     1= Trac plugins =
     2[[TracGuideToc]]
     3
     4From 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
     8From 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
     12To use egg-based plugins in Trac, you need to have [http://peak.telecommunity.com/DevCenter/setuptools setuptools] (version 0.6) installed.
    1413
    1514To install `setuptools`, download the bootstrap module [http://peak.telecommunity.com/dist/ez_setup.py ez_setup.py] and execute it as follows:
    1615
    17 {{{#!sh
     16{{{
    1817$ python ez_setup.py
    1918}}}
    2019
    21 If the `ez_setup.py` script fails to install the setuptools release, you can download it from [pypi:setuptools PyPI] and install it manually.
     20If 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.
    2221
    2322Plugins can also consist of a single `.py` file dropped directly into either the project's or the shared `plugins` directory.
    2423
    25 == Installing a Trac plugin
    26 
    27 === For a single project
     24== Installing a Trac plugin ==
     25
     26=== For a single project ===
    2827
    2928Plugins are typically packaged as [http://peak.telecommunity.com/DevCenter/PythonEggs Python eggs]. That means they are .zip archives with the file extension `.egg`.
     
    3332 * Unpack the source. It should provide `setup.py`.
    3433 * Run:
    35  {{{#!sh
     34
     35{{{
    3636$ python setup.py bdist_egg
    3737}}}
    3838
    39 You should now have an *.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, ie kill the process and run again.
     39You should have a *.egg file. Examine the output of running python to find where this was created.
     40
     41Once 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).
    4242
    4343To uninstall a plugin installed this way, remove the egg from the `plugins` directory and restart the web server.
    4444
    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 [trac:SpamFilter SpamFilter], are downloadable as an `.egg` file that can be installed with `easy_install` or `pip`:
    54 {{{#!sh
    55 $ easy_install TracSpamFilter
    56 $ pip install TracSpamFilter
    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 TracSpamFilter-0.4.1_r10106-py2.6.egg
    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
     45Note: 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
     47Note 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
     53Some plugins (such as [trac:SpamFilter SpamFilter]) are downloadable as an `.egg` file that can be installed with the `easy_install` program:
     54{{{
     55easy_install TracSpamFilter
     56}}}
     57
     58If `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
     60If 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{{{
     62easy_install --always-unzip TracSpamFilter-0.4.1_r10106-py2.6.egg
     63}}}
     64You should end up with a directory having the same name as the zipped egg (complete with `.egg` extension) and containing its uncompressed contents.
     65
     66Trac 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 ====
    7269
    7370`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:
    74 {{{#!sh
    75 $ easy_install http://svn.edgewall.com/repos/trac/plugins/0.12/spam-filter-captcha
    76 }}}
    77 
    78 ==== Enabling the plugin
    79 
    80 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, ie the path specified in the `[inherit] plugins_dir` configuration option.
    81 
    82 This is done in the `[components]` section of the configuration file `trac.ini`. For example:
    83 {{{#!ini
     71{{{
     72easy_install http://svn.edgewall.com/repos/trac/plugins/0.12/spam-filter-captcha
     73}}}
     74
     75==== Enabling the plugin ====
     76
     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 the 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:
     80{{{
    8481[components]
    8582tracspamfilter.* = enabled
    8683}}}
    8784
    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:
     85The 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
     87Note: 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:
    10592
    10693 1. Do `easy_install -m [plugin name]` to remove references from `$PYTHONLIB/site-packages/easy-install.pth` when the plugin installed by setuptools.
    10794 1. Delete executables from `/usr/bin`, `/usr/local/bin`, or `C:\\Python*\Scripts`. To find what executables are involved, refer to the `[console-script]` section of `setup.py`.
    108  1. Delete the .egg file or folder from where it's installed, usually inside `$PYTHONLIB/site-packages/`.
     95 1. Delete the .egg file or folder from where it's installed (usually inside `$PYTHONLIB/site-packages/`).
    10996 1. Restart the web server.
    11097
    111 If you are uncertain about the location of the egg file, you can try to locate it by replacing `myplugin` with whatever namespace the plugin uses (as used when enabling the plugin):
    112 {{{#!pycon
     98If 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):
     99{{{
    113100>>> import myplugin
    114101>>> print myplugin.__file__
     
    116103}}}
    117104
    118 == Setting up the plugin cache
    119 
    120 Some plugins will need to be extracted by the Python egg's 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.
     105== Setting up the plugin cache ==
     106
     107Some 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.
    121108
    122109To do this from the Apache configuration, use the `SetEnv` directive:
    123 {{{#!apache
     110{{{
    124111SetEnv PYTHON_EGG_CACHE /path/to/dir
    125112}}}
    126113
    127 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], ie in the same `<Location>` block.
    128 
    129 For example for CGI:
    130 {{{#!apache
     114This 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.
     115
     116For example (for CGI):
     117{{{
    131118 <Location /trac>
    132119   SetEnv TRAC_ENV /path/to/projenv
     
    135122}}}
    136123
    137 Or for mod_python:
    138 {{{#!apache
     124Or (for mod_python):
     125{{{
    139126 <Location /trac>
    140127   SetHandler mod_python
     
    144131}}}
    145132
    146 '''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.
     133 ''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.''
    147134
    148135For [wiki:TracFastCgi FastCGI], you'll need to `-initial-env` option, or whatever is provided by your web server for setting environment variables.
    149136
    150 '''Note''': 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:
    151 
    152 {{{#!apache
     137 ''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.
     138
     139{{{
    153140FastCgiConfig -initial-env TRAC_ENV=/var/lib/trac -initial-env PYTHON_EGG_CACHE=/var/lib/trac/plugin-cache
    154141}}}
    155142
    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:
     143=== About hook scripts ===
     144
     145If 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
     151Try this from the command line:
     152{{{
     153$ python -c "import pkg_resources"
     154}}}
     155
     156If 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
     160Python 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
     162Also, 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
     166If 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
     174Trac must be able to read the .egg file.
     175
     176=== Check the log files ===
     177
     178Enable [wiki:TracLogging logging] and set the log level to `DEBUG`, then watch the log file for messages about loading plugins.
     179
     180=== Verify you have proper permissions ===
     181
     182Some 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.
     183
     184=== Is the wrong version of the plugin loading? ===
     185
     186If 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:
     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.
     192
     193=== If all of the above failed ===
     194
     195Okay, 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
     199The WebAdmin plugin (part of the core since 0.11) offers limited support for plugin configuration through the web to users with `TRAC_ADMIN` permission:
    163200
    164201* en/disabling installed plugins
    165202* installing plugins by uploading them as eggs
    166203
    167 If you wish to disable the second function for security reasons, add the following to your `trac.ini` file:
    168 {{{#!ini
    169 [components]
     204You probably want to disable the second function for security reasons: in `trac.ini`, in the `[components]` section, add the line
     205{{{
    170206trac.admin.web_ui.PluginAdminPanel = disabled
    171207}}}
    172208This disables the whole panel, so the first function will no longer be available either.
    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!
    224209
    225210----