Changes between Version 4 and Version 5 of TracPlugins


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Timestamp:
Jul 31, 2015, 2:19:56 PM (5 years ago)
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trac
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  • TracPlugins

    v4 v5  
    1 = Trac plugins =
     1= Trac plugins
     2
    23[[TracGuideToc]]
    34
    45Trac is extensible with [trac:PluginList plugins]. Plugin functionality is based on the [trac:TracDev/ComponentArchitecture component architecture], with peculiarities described in the [trac:TracDev/PluginDevelopment plugin development] page.
    56
    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.
     7== Plugin discovery
     8
     9From 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 trac.ini.
     10
     11== Requirements for Trac eggs
     12
     13To use egg-based plugins in Trac, you need to have [http://peak.telecommunity.com/DevCenter/setuptools setuptools] (version >= 0.6) installed.
    1314
    1415To install `setuptools`, download the bootstrap module [http://peak.telecommunity.com/dist/ez_setup.py ez_setup.py] and execute it as follows:
    1516
    16 {{{
     17{{{#!sh
    1718$ python ez_setup.py
    1819}}}
     
    2223Plugins can also consist of a single `.py` file dropped directly into either the project's or the shared `plugins` directory.
    2324
    24 == Installing a Trac plugin ==
    25 
    26 === For a single project ===
     25== Installing a Trac plugin
     26
     27=== For a single project
    2728
    2829Plugins are typically packaged as [http://peak.telecommunity.com/DevCenter/PythonEggs Python eggs]. That means they are .zip archives with the file extension `.egg`.
     
    3334 * Run:
    3435
    35 {{{
     36{{{#!sh
    3637$ python setup.py bdist_egg
    3738}}}
    3839
    39 You should have a *.egg file. Examine the output of running python to find where this was created.
     40You should have a *.egg file. Examine the output of running Python to find where this was created.
    4041
    4142Once 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).
     
    4344To uninstall a plugin installed this way, remove the egg from the `plugins` directory and restart the web server.
    4445
    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).
     46'''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 2.6, but have upgraded your standalone Python to 2.7, the eggs won't be recognized.
     47
     48'''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.
     49
     50=== For all projects
     51
     52==== With an .egg file
     53
     54Some plugins, such as [trac:SpamFilter SpamFilter], are downloadable as an `.egg` file that can be installed with `easy_install` or `pip`:
     55{{{#!sh
     56$ easy_install TracSpamFilter
     57$ pip install TracSpamFilter
     58}}}
     59
     60If `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.
     61
     62`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].
    5963
    6064If 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
     65{{{#!sh
     66$ easy_install --always-unzip TracSpamFilter-0.4.1_r10106-py2.6.egg
    6367}}}
    6468You should end up with a directory having the same name as the zipped egg (complete with `.egg` extension) and containing its uncompressed contents.
     
    6670Trac 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.
    6771
    68 ==== From source ====
     72==== From source
    6973
    7074`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:
    71 {{{
    72 easy_install http://svn.edgewall.com/repos/trac/plugins/0.12/spam-filter-captcha
    73 }}}
    74 
    75 ==== Enabling the plugin ====
    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.
     75{{{#!sh
     76$ easy_install http://svn.edgewall.com/repos/trac/plugins/0.12/spam-filter-captcha
     77}}}
     78
     79==== Enabling the plugin
     80
     81Unlike 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.
    7882
    7983This is done in the `[components]` section of the configuration file. For example:
    80 {{{
     84{{{#!ini
    8185[components]
    8286tracspamfilter.* = enabled
     
    8589The 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`).
    8690
    87 Note: After installing the plugin, you must restart your web server.
    88 
    89 ==== Uninstalling ====
     91After installing the plugin, you must restart your web server.
     92
     93==== Uninstalling
    9094
    9195`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:
     
    97101
    98102If 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 {{{
     103{{{#!pycon
    100104>>> import myplugin
    101105>>> print myplugin.__file__
     
    103107}}}
    104108
    105 == Setting up the plugin cache ==
     109== Setting up the plugin cache
    106110
    107111Some 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.
    108112
    109113To do this from the Apache configuration, use the `SetEnv` directive:
    110 {{{
     114{{{#!apache
    111115SetEnv PYTHON_EGG_CACHE /path/to/dir
    112116}}}
    113117
    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.
     118This 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.
    115119
    116120For example (for CGI):
    117 {{{
     121{{{#!apache
    118122 <Location /trac>
    119123   SetEnv TRAC_ENV /path/to/projenv
     
    123127
    124128Or (for mod_python):
    125 {{{
     129{{{#!apache
    126130 <Location /trac>
    127131   SetHandler mod_python
     
    131135}}}
    132136
    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.''
     137'''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.
    134138
    135139For [wiki:TracFastCgi FastCGI], you'll need to `-initial-env` option, or whatever is provided by your web server for setting environment variables.
    136140
    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 {{{
     141'''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:
     142
     143{{{#!apache
    140144FastCgiConfig -initial-env TRAC_ENV=/var/lib/trac -initial-env PYTHON_EGG_CACHE=/var/lib/trac/plugin-cache
    141145}}}
    142146
    143 === About hook scripts ===
     147=== About hook scripts
    144148
    145149If 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.
    146150
    147 == Troubleshooting ==
    148 
    149 === Is setuptools properly installed? ===
     151== Troubleshooting
     152
     153=== Is setuptools properly installed?
    150154
    151155Try this from the command line:
    152 {{{
     156{{{#!sh
    153157$ python -c "import pkg_resources"
    154158}}}
     
    156160If you get '''no output''', setuptools '''is''' installed. Otherwise, you'll need to install it before plugins will work in Trac.
    157161
    158 === Did you get the correct version of the Python egg? ===
     162=== Did you get the correct version of the Python egg?
    159163
    160164Python 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).
     
    162166Also, 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.
    163167
    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 ===
     168=== Is the plugin enabled?
     169
     170If 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:
     171
     172 * you actually added the necessary line(s) to the `[components]` section.
     173 * the package/module names are correct.
     174 * the value is "enabled", not "enable" or "Enable".
     175 * the section name is "components", not "component".
     176
     177=== Check the permissions on the .egg file
    174178
    175179Trac must be able to read the .egg file.
    176180
    177 === Check the log files ===
     181=== Check the log files
    178182
    179183Enable [wiki:TracLogging logging] and set the log level to `DEBUG`, then watch the log file for messages about loading plugins.
    180184
    181 === Verify you have proper permissions ===
     185=== Verify you have proper permissions
    182186
    183187Some 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.
    184188
    185 === Is the wrong version of the plugin loading? ===
     189=== Is the wrong version of the plugin loading?
    186190
    187191If 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:
     
    192196 * 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.
    193197
    194 === If all of the above failed ===
     198=== If all of the above failed
    195199
    196200Okay, 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!
    197201
    198 == Web-based plugin administration ==
     202== Web-based plugin administration
    199203
    200204The [trac:WebAdmin] interface offers limited support for plugin configuration through the web to users with `TRAC_ADMIN` permission:
     
    203207* installing plugins by uploading them as eggs
    204208
    205 You probably want to disable the second function for security reasons: in `trac.ini`, in the `[components]` section, add the line
    206 {{{
     209If you wish to disable the second function for security reasons, add the following to the `[components]` section of trac.ini:
     210{{{#!ini
    207211trac.admin.web_ui.PluginAdminPanel = disabled
    208212}}}