The python plugin

The python plugin can be used by either Python 2 or Python 3 based parts using one of the following:

  • a requirements.txt file used to import Python modules
  • a setup.py script for building the project
  • packages installed directly from pip

This plugin uses the common plugin keywords as well as those for “sources”. For more information, see Snapcraft parts metadata.

Plugin-specific features and syntax are dependent on which base is being used, as outlined below:

See Python applications for a simple example, or search GitHub for projects already using the plugin.

This is a snapcraft plugin. See Snapcraft plugins and Supported plugins for further details on how plugins are used.

base: core20

This plugin uses the following plugin-specific keywords:

  • requirements (array)
    List of paths to requirements.txt file(s)
  • constraints (string)
    Path to a constraints file.
  • python-packages (list)
    A list of dependencies to install using pip. This supports the same syntax as the pip install command.

This plugin also interprets these specific build-environment entries:

  • SNAPCRAFT_PYTHON_INTERPRETER
    (default: python3)
    The interpreter binary to search for in PATH.

  • SNAPCRAFT_PYTHON_VENV_ARGS
    Additional arguments for venv.

By default, this plugin uses Python from the base snap. If a part using this plugin uses a build-base other than that of the base, or a different interpreter is desired, it must be bundled in the snap (including venv) and must be in PATH.

It is required to bundle python when creating a snap that uses classic confinement, this can be accomplished on Ubuntu by adding stage-packages (i.e.; python3-venv).

Use of python3- in stage-packages will force the inclusion of the python interpreter.

Requires Snapcraft version 4.0+.

base: core18 | core

This plugin uses the following plugin-specific keywords:

  • requirements (array)
    List of paths to requirements.txt file(s)

  • constraints (string)
    Path to a constraints file

  • process-dependency-links (bool; default: false)
    Enable the processing of dependency links in pip, which allow one
    project to provide places to look for another project

  • python-packages (list)
    A list of dependencies to install using pip. This supports the same syntax as the pip install command. For example:

    python-packages:
      - docopt == 0.6.1  # Install specific versions
      - git+https://github.com/inuits/mkdocs-factsheet.git  # Install from a git repository
      - https://github.com/cmacmackin/markdown-include/archive/v0.5.1.tar.gz  # Install from an archive
    

    See the pip install docs for more information.

  • python-version (string; default: python3)
    The python version to use. Valid options are python2 and python3

The python plugin also searches <stage-dir>/usr/bin/<python-interpreter> for a Python interpreter with a basename matching python-version in the <stage> directory. If detected, this takes preference and stage-packages will not use its own interpreter.

Last updated 3 months ago. Help improve this document in the forum.