.. _example-python-app:

Example Python app
==================

This how-to guide covers the steps, decisions, and implementation details that
are unique when crafting a Python-based snap. We'll work through the aspects
unique to Python apps by examining an existing recipe.

The process of developing a snap for a Python app builds on top of standard
Python packaging tools and configuration, making it possible to adapt or
integrate an app's existing build tooling into the crafting process.


Example recipe for liquidctl
----------------------------

The following code comprises the recipe of a Python project, `liquidctl
<https://snapcraft.io/liquidctl>`_. This project is both a driver and a CLI
tool for power and cooling components in PCs.

.. collapse:: liquidctl recipe

  .. literalinclude:: ../code/craft-a-snap/example-python-recipe.yaml
    :language: yaml
    :lines: 2-


Add a part written in Python
----------------------------

.. literalinclude:: ../code/craft-a-snap/example-python-recipe.yaml
  :language: yaml
  :start-at: parts:
  :end-at: - python3-usb

Python parts are built with the :ref:`Python plugin <python_plugin>`.

To add a Python part:

#. Declare the general part keys, such as ``source``, ``override-build``,
   ``build-packages``, and so on.
#. Set ``plugin: python``.