~bzr-pqm/bzr/bzr.dev

Writing a plugin

================

Introduction

------------

Plugins are very similar to bzr core functionality.  They can import

anything in bzrlib.  A plugin may simply override standard functionality,

but most plugins supply new commands.

Creating a new command

----------------------

To create a command, make a new object that derives from

``bzrlib.commands.Command``, and name it ``cmd_foo``, where foo is the name of

your command.  If you create a command whose name contains an underscore,

it will appear in the UI with the underscore turned into a hyphen.  For

example, `cmd_baz_import` will appear as `baz-import`.  For examples of how

to write commands, please see ``builtins.py``.

Once you've created a command you must register the command with

``bzrlib.commands.register_command(cmd_foo)``.  You must register the

command when your file is imported, otherwise bzr will not see it.

Specifying a plugin version number

----------------------------------

Simply define ``version_info`` to be a tuple defining the current version

number of your plugin. eg.

``version_info = (0, 9, 0)``

``version_info = (0, 9, 0, 'dev', 0)``

Plugin searching rules

----------------------

Bzr will scan ``bzrlib/plugins`` and ``~/.bazaar/plugins`` for plugins

by default.  You can override this with ``BZR_PLUGIN_PATH``.  Plugins

may be either modules or packages.  If your plugin is a single file,

you can structure it as a module.  If it has multiple files, or if you

want to distribute it as a bzr branch, you should structure it as a

package, i.e. a directory with an ``__init__.py`` file.

More information

----------------

Please feel free to contribute your plugin to BzrTools, if you think it

would be useful to other people.

See the `Bazaar Developer Guide`_ for details on Bazaar's development

guidelines and policies.

.. _Bazaar Developer Guide: ../developer-guide/HACKING.html