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..
Except where otherwise noted, this document is licensed under Creative
Commons Attribution 3.0 License. You can view the license at:
https://creativecommons.org/licenses/by/3.0/
.. _plugin-base_setup:
=======================================
Create a third-party plugin for Watcher
=======================================
Watcher provides a plugin architecture which allows anyone to extend the
existing functionalities by implementing third-party plugins. This process can
be cumbersome so this documentation is there to help you get going as quickly
as possible.
Pre-requisites
==============
We assume that you have set up a working Watcher development environment. So if
this not already the case, you can check out our documentation which explains
how to set up a :ref:`development environment
<watcher_development_environment>`.
.. _development environment:
Third party project scaffolding
===============================
First off, we need to create the project structure. To do so, we can use
`cookiecutter`_ and the `OpenStack cookiecutter`_ project scaffolder to
generate the skeleton of our project::
$ virtualenv thirdparty
$ . thirdparty/bin/activate
$ pip install cookiecutter
$ cookiecutter https://github.com/openstack-dev/cookiecutter
The last command will ask you for many information, and If you set
``module_name`` and ``repo_name`` as ``thirdparty``, you should end up with a
structure that looks like this::
$ cd thirdparty
$ tree .
.
├── babel.cfg
├── CONTRIBUTING.rst
├── doc
│ └── source
│ ├── conf.py
│ ├── contributing.rst
│ ├── index.rst
│ ├── installation.rst
│ ├── readme.rst
│ └── usage.rst
├── HACKING.rst
├── LICENSE
├── MANIFEST.in
├── README.rst
├── requirements.txt
├── setup.cfg
├── setup.py
├── test-requirements.txt
├── thirdparty
│ ├── __init__.py
│ └── tests
│ ├── base.py
│ ├── __init__.py
│ └── test_thirdparty.py
└── tox.ini
**Note:** You should add `python-watcher`_ as a dependency in the
requirements.txt file::
# Watcher-specific requirements
python-watcher
.. _cookiecutter: https://github.com/audreyr/cookiecutter
.. _OpenStack cookiecutter: https://github.com/openstack-dev/cookiecutter
.. _python-watcher: https://pypi.org/project/python-watcher
Implementing a plugin for Watcher
=================================
Now that the project skeleton has been created, you can start the
implementation of your plugin. As of now, you can implement the following
plugins for Watcher:
- A :ref:`goal plugin <implement_goal_plugin>`
- A :ref:`strategy plugin <implement_strategy_plugin>`
- An :ref:`action plugin <implement_action_plugin>`
- A :ref:`planner plugin <implement_planner_plugin>`
- A workflow engine plugin
- A :ref:`cluster data model collector plugin
<implement_cluster_data_model_collector_plugin>`
If you want to learn more on how to implement them, you can refer to their
dedicated documentation.
|
