Changes between Version 6 and Version 7 of TracPlugins


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Timestamp:
Aug 24, 2019, 7:16:43 AM (5 years ago)
Author:
trac
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  • TracPlugins

    v6 v7  
    77== Plugin discovery
    88
    9 From the user's point of view, a plugin is either a standalone .py file or a package (egg or wheel). 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.
     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 the `trac.ini` file.
     10
     11== Requirements for Trac eggs #Requirements
     12
     13To use egg-based plugins in Trac, you need to have [http://peak.telecommunity.com/DevCenter/setuptools setuptools] (version >= 0.6) installed.
     14
     15To install `setuptools`, download the bootstrap module [http://peak.telecommunity.com/dist/ez_setup.py ez_setup.py] and execute it as follows:
     16
     17{{{#!sh
     18$ python ez_setup.py
     19}}}
     20
     21If the `ez_setup.py` script fails to install the setuptools release, you can download it from [pypi:setuptools PyPI] and install it manually.
     22
     23Plugins can also consist of a single `.py` file dropped directly into either the project's or the shared `plugins` directory.
    1024
    1125== Installing a Trac plugin
    … …  
    2539You should now have an *.egg file. Examine the output of running Python to find where this was created.
    2640
    27 Once you have the plugin archive, copy it into the `plugins` directory of the [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 [TracStandalone "tracd" standalone server], restart tracd, ie kill the process and run again.
     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, ie kill the process and run again.
    2842
    2943To uninstall a plugin installed this way, remove the egg from the `plugins` directory and restart the web server.
    … …  
    4054{{{#!sh
    4155$ easy_install TracTags
    42 }}}
    43 {{{#!sh
    4456$ pip install TracTags
    4557}}}
    4658
    47 If `easy_install` is not on your system, see the [trac:setuptools#Installsetuptools Trac setuptools documentation].
     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:\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.
    4860
    4961`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].
    … …  
    5971==== From source
    6072
    61 `easy_install` and `pip` make installing from source a snap. Just give it the URL to either a repository or a tarball/zip of the source:
     73`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:
    6274{{{#!sh
    6375$ easy_install https://trac-hacks.org/svn/tagsplugin/trunk
    6476}}}
    65 {{{#!sh
    66 $ pip install svn+https://trac-hacks.org/svn/tagsplugin/trunk
    67 }}}
    68 When installing from a repository using `pip`, be sure to use the repository type in the protocol. For example, `svn+https` for Subversion and `git+https` for Git.
    6977
    7078==== Enabling the plugin
    7179
    72 Unlike plugins installed per environment, you'll have to explicitly enable globally installed plugins via [TracIni trac.ini]. This also applies to plugins installed in the shared plugins directory, ie the path specified in the [TracIni#inherit-plugins_dir-option "[inherit] plugins_dir"] configuration option.
    73 
    74 This is done in the [TracIni#components-section "[components]"] section of the configuration file `trac.ini`. For example:
     80Unlike 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
     82This is done in the `[components]` section of the configuration file `trac.ini`. For example:
    7583{{{#!ini
    7684[components]
    … …  
    111119}}}
    112120
    113 ==== Upgrading a Plugin
    114 
    115 Normally, upgrading a plugin is simply a matter of repeating the install process. You may want to [#Uninstalling uninstall] old versions of the plugin.
    116 
    117 The `pip install` command has an `--upgrade (-U)` switch that will uninstall the old version and install the new version. The command can have some unintended side-effects though, because it will also upgrade the plugin dependencies. For example, if `Trac` is listed as a dependency of the plugin in `setup.py`, the latest version of Trac will be downloaded and installed. This may not be what you want if you are running an older version of Trac because not all your plugins are compatible with the latest version of Trac, or you simply haven't done the appropriate planning for upgrading Trac. Uninstalling and then installing the plugin can be a safer option:
    118 {{{#!sh
    119 $ pip uninstall <pluginname>
    120 $ pip install <pluginname>
    121 }}}
    122 
    123 Alternatively you can use a [https://pip.pypa.io/en/stable/user_guide/#requirements-files requirements file] and pin the versions of the packages that you don't want to implicitly upgrade.
    124 
    125121==== Uninstalling
    126122
    127 `pip` makes it easy to uninstall a plugin:
    128 {{{#!sh
    129 $ pip uninstall <pluginname>
    130 }}}
    131 
    132 The `pip uninstall` command can be used even if the plugin was installed using `easy_install` or `python setup.py install`.
    133 
    134123Neither `easy_install` nor `python setup.py` have an uninstall feature. However, it is usually trivial to remove a globally installed egg and reference:
    135124
    136  1. Do `easy_install -m <plugin name>` to remove references from `$PYTHONLIB/site-packages/easy-install.pth` when the plugin is installed by setuptools.
     125 1. Do `easy_install -m [plugin name]` to remove references from `$PYTHONLIB/site-packages/easy-install.pth` when the plugin installed by setuptools.
    137126 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`.
    138127 1. Delete the .egg file or folder from where it's installed, usually inside `$PYTHONLIB/site-packages/`.
    … …  
    148137== Setting up the plugin cache
    149138
    150 Some plugins will need to be extracted by the Python egg's runtime. See [wiki:TracInstall#egg-cache] for information on setting up the egg cache.
     139Some 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.
     140
     141To do this from the Apache configuration, use the `SetEnv` directive:
     142{{{#!apache
     143SetEnv PYTHON_EGG_CACHE /path/to/dir
     144}}}
     145
     146This 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.
     147
     148For example for CGI:
     149{{{#!apache
     150 <Location /trac>
     151   SetEnv TRAC_ENV /path/to/projenv
     152   SetEnv PYTHON_EGG_CACHE /path/to/dir
     153 </Location>
     154}}}
     155
     156Or for mod_python:
     157{{{#!apache
     158 <Location /trac>
     159   SetHandler mod_python
     160   ...
     161   SetEnv PYTHON_EGG_CACHE /path/to/dir
     162 </Location>
     163}}}
     164
     165'''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.
     166
     167For [wiki:TracFastCgi FastCGI], you'll need to `-initial-env` option, or whatever is provided by your web server for setting environment variables.
     168
     169'''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:
     170
     171{{{#!apache
     172FastCgiConfig -initial-env TRAC_ENV=/var/lib/trac -initial-env PYTHON_EGG_CACHE=/var/lib/trac/plugin-cache
     173}}}
     174
     175=== About hook scripts
     176
     177If 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.
    151178
    152179== Web-based plugin administration
    153180
    154 The !WebAdmin interface offers limited support for plugin configuration to users with `TRAC_ADMIN` permission:
    155 
    156 * enabling and disabling installed plugins
     181The !WebAdmin interface offers limited support for plugin configuration through the web to users with `TRAC_ADMIN` permission:
     182
     183* en/disabling installed plugins
    157184* installing plugins by uploading them as eggs
    158185
    … …  
    164191This disables the whole panel, so the first function will no longer be available either.
    165192
     193== Writing Trac Plugins
     194
     195You can write your own Trac plugin using the following resources:
     196* [trac:TracDev Developer documentation]
     197* [https://trac-hacks.org Examples on trac-hacks.org]
     198* [trac:browser:branches/1.2-stable/sample-plugins sample-plugins]
     199
    166200== Troubleshooting
    167201
    … …  
    196230=== Check the log files
    197231
    198 Enable [TracLogging logging] and set the log level to `DEBUG`, then watch the log file for messages about loading plugins.
     232Enable [wiki:TracLogging logging] and set the log level to `DEBUG`, then watch the log file for messages about loading plugins.
    199233
    200234=== Verify you have the proper permissions
    … …  
    204238=== Is the wrong version of the plugin loading?
    205239
    206 If you put your plugins inside the `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:
     240If 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:
    207241
    208242 * 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.
    … …  
    213247=== If all of the above failed
    214248
    215 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] or [trac:MailingList] and ask away!
     249Okay, 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!
    216250
    217251----