Changes between Version 3 and Version 4 of Trac Plugins


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Timestamp:
Apr 12, 2015, 9:30:13 PM (10 years ago)
Author:
trac
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  • Trac Plugins

    v3 v4  
    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== Plugin discovery
    78
    89From 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.
    910
    10 == Requirements for Trac eggs ==
     11== Requirements for Trac eggs
    1112
    1213To use egg-based plugins in Trac, you need to have [http://peak.telecommunity.com/DevCenter/setuptools setuptools] (version 0.6) installed.
    … …  
    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 2.5, but have upgraded your standalone Python to 2.6, 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`:
     55{{{#!sh
     56$ easy_install TracSpamFilter
     57}}}
     58
     59If `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.
    5960
    6061If 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
     62{{{#!sh
     63$ easy_install --always-unzip TracSpamFilter-0.4.1_r10106-py2.6.egg
    6364}}}
    6465You should end up with a directory having the same name as the zipped egg (complete with `.egg` extension) and containing its uncompressed contents.
    … …  
    6667Trac 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.
    6768
    68 ==== From source ====
     69==== From source
    6970
    7071`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.
     72{{{#!sh
     73$ easy_install http://svn.edgewall.com/repos/trac/plugins/0.12/spam-filter-captcha
     74}}}
     75
     76==== Enabling the plugin
     77
     78Unlike 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.
    7879
    7980This is done in the `[components]` section of the configuration file. For example:
    80 {{{
     81{{{#!ini
    8182[components]
    8283tracspamfilter.* = enabled
    … …  
    8586The 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`).
    8687
    87 Note: After installing the plugin, you must restart your web server.
    88 
    89 ==== Uninstalling ====
     88After installing the plugin, you must restart your web server.
     89
     90==== Uninstalling
    9091
    9192`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:
    … …  
    9798
    9899If 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 {{{
     100{{{#!pycon
    100101>>> import myplugin
    101102>>> print myplugin.__file__
    … …  
    103104}}}
    104105
    105 == Setting up the plugin cache ==
     106== Setting up the plugin cache
    106107
    107108Some 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.
    108109
    109110To do this from the Apache configuration, use the `SetEnv` directive:
    110 {{{
     111{{{#!apache
    111112SetEnv PYTHON_EGG_CACHE /path/to/dir
    112113}}}
    113114
    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.
     115This 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.
    115116
    116117For example (for CGI):
    117 {{{
     118{{{#!apache
    118119 <Location /trac>
    119120   SetEnv TRAC_ENV /path/to/projenv
    … …  
    123124
    124125Or (for mod_python):
    125 {{{
     126{{{#!apache
    126127 <Location /trac>
    127128   SetHandler mod_python
    … …  
    131132}}}
    132133
    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.''
     134'''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.
    134135
    135136For [wiki:TracFastCgi FastCGI], you'll need to `-initial-env` option, or whatever is provided by your web server for setting environment variables.
    136137
    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 {{{
     138'''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:
     139
     140{{{#!apache
    140141FastCgiConfig -initial-env TRAC_ENV=/var/lib/trac -initial-env PYTHON_EGG_CACHE=/var/lib/trac/plugin-cache
    141142}}}
    142143
    143 === About hook scripts ===
     144=== About hook scripts
    144145
    145146If 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.
    146147
    147 == Troubleshooting ==
    148 
    149 === Is setuptools properly installed? ===
     148== Troubleshooting
     149
     150=== Is setuptools properly installed?
    150151
    151152Try this from the command line:
    152 {{{
     153{{{#!sh
    153154$ python -c "import pkg_resources"
    154155}}}
    … …  
    156157If you get '''no output''', setuptools '''is''' installed. Otherwise, you'll need to install it before plugins will work in Trac.
    157158
    158 === Did you get the correct version of the Python egg? ===
     159=== Did you get the correct version of the Python egg?
    159160
    160161Python 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).
    … …  
    162163Also, 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.
    163164
    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 ===
     165=== Is the plugin enabled?
     166
     167If 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:
     168
     169 * you actually added the necessary line(s) to the `[components]` section.
     170 * the package/module names are correct.
     171 * the value is "enabled", not "enable" or "Enable".
     172 * the section name is "components", not "component".
     173
     174=== Check the permissions on the .egg file
    174175
    175176Trac must be able to read the .egg file.
    176177
    177 === Check the log files ===
     178=== Check the log files
    178179
    179180Enable [wiki:TracLogging logging] and set the log level to `DEBUG`, then watch the log file for messages about loading plugins.
    180181
    181 === Verify you have proper permissions ===
     182=== Verify you have proper permissions
    182183
    183184Some 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.
    184185
    185 === Is the wrong version of the plugin loading? ===
     186=== Is the wrong version of the plugin loading?
    186187
    187188If 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:
    … …  
    192193 * 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.
    193194
    194 === If all of the above failed ===
     195=== If all of the above failed
    195196
    196197Okay, 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!
    197198
    198 == Web-based plugin administration ==
    199 
    200 The WebAdmin interface offers limited support for plugin configuration through the web to users with `TRAC_ADMIN` permission:
     199== Web-based plugin administration
     200
     201The [trac:WebAdmin] interface offers limited support for plugin configuration through the web to users with `TRAC_ADMIN` permission:
    201202
    202203* en/disabling installed plugins
    203204* installing plugins by uploading them as eggs
    204205
    205 You probably want to disable the second function for security reasons: in `trac.ini`, in the `[components]` section, add the line
    206 {{{
     206If you wish to disable the second function for security reasons, add the following to the `[components]` section of trac.ini:
     207{{{#!ini
    207208trac.admin.web_ui.PluginAdminPanel = disabled
    208209}}}