Table of Contents (3.3.22)

# Using plugins

## What is a plugin?

A plugin is an external component for Breezy that is typically made by third parties. A plugin is capable of augmenting Breezy by adding new functionality. A plugin can also change current Breezy behavior by replacing current functionality. Sample applications of plugins are:

- overriding commands

- adding new commands

- providing additional network transports

- customizing log output.

The sky is the limit for the customization that can be done through plugins. In fact, plugins often work as a way for developers to test new features for Breezy prior to inclusion in the official codebase. Plugins are helpful at feature retirement time as well, e.g. deprecated file formats may one day be removed from the Breezy core and be made available as a plugin instead.

Plugins are good for users, good for external developers and good for Breezy itself.

## Where to find plugins

We keep our list of plugins on the http://wiki.breezy-vcs.org/Plugins page.

## How to install a plugin

Installing a plugin is very easy! If not already created, create a `plugins` directory under your Breezy configuration directory, `~/.config/breezy/` on Unix and `C:\Documents and Settings\<username>\Application Data\Breezy\2.0\` on Windows. Within this directory (referred to as $BRZ_HOME below), each plugin is placed in its own subdirectory.

Plugins work particularly well with Breezy branches. For example, to install the brztools plugins for your main user account on GNU/Linux, one can perform the following:

    brz branch http://panoramicfeedback.com/opensource/brz/brztools
    ~/.config/breezy/plugins/brztools

When installing plugins, the directories that you install them in must be valid python identifiers. This means that they can only contain certain characters, notably they cannot contain hyphens (`-`). Rather than installing `brz-gtk` to `$BRZ_HOME/plugins/brz-gtk`, install it to `$BRZ_HOME/plugins/gtk`.

## Alternative plugin locations

If you have the necessary permissions, plugins can also be installed on a system-wide basis. One can additionally override the personal plugins location by setting the environment variable `BRZ_PLUGIN_PATH` (see User Reference for a detailed explanation).

## Listing the installed plugins

To do this, use the plugins command like this:

    brz plugins

The name, location and version of each plugin installed will be displayed.

New commands added by plugins can be seen by running `brz help commands`. The commands provided by a plugin are shown followed by the name of the plugin in brackets.

## Popular plugins

Here is a sample of some of the more popular plugins.

> Category | Name | Description
> --- | --- | ---
> GUI | QBzr | Qt-based GUI tools
> General | brztools | misc. enhancements including shelf
> General | difftools | external diff tool helper
> General | extmerge | external merge tool helper
> Integration | brz-svn | use Subversion as a repository
> Migration | cvsps | migrate CVS patch-sets

Note that there are also a number of plugins for Bazaar that have not yet been ported to Python 3 and Breezy.

If you wish to write your own plugins, it is not difficult to do. See Writing a plugin in the appendices to get started. See http://doc.bazaar.canonical.com/plugins/en/ for details.