setup-python

This action provides the following functionality for GitHub Actions users:

• Installing a version of Python or PyPy and (by default) adding it to the PATH
• Optionally caching dependencies for pip, pipenv and poetry
• Registering problem matchers for error output

Breaking changes in V6

• Upgraded action from node20 to node24

  Make sure your runner is on version v2.327.1 or later to ensure compatibility with this release. See Release Notes

For more details, see the full release notes on the releases page

Basic usage

See action.yml

Python

PyPy

GraalPy

Free threaded Python

The

input is optional. If not supplied, the action will try to resolve the version from the default

.python-version

file. If the

.python-version

file doesn't exist Python or PyPy version from the PATH will be used. The default version of Python or PyPy in PATH varies between runners and can be changed unexpectedly so we recommend always setting Python version explicitly using the

python-version

or

python-version-file

inputs.

The action will first check the local tool cache for a semver match. If unable to find a specific version in the tool cache, the action will attempt to download a version of Python from GitHub Releases and for PyPy from the official PyPy's dist.

For information regarding locally cached versions of Python or PyPy on GitHub hosted runners, check out GitHub Actions Runner Images.

Supported version syntax

The

input supports the Semantic Versioning Specification and some special version notations (e.g.

semver ranges

,

x.y-dev syntax

, etc.), for detailed examples please refer to the section: Using python-version input of the Advanced usage guide.

Supported architectures

Using the

input, it is possible to specify the required Python or PyPy interpreter architecture:

x86

,

x64

, or

arm64

. If the input is not specified, the architecture defaults to the host OS architecture.

Caching packages dependencies

The action has built-in functionality for caching and restoring dependencies. It uses toolkit/cache under the hood for caching dependencies but requires less configuration settings. Supported package managers are

,

pipenv

and

poetry

. The

cache

input is optional, and caching is turned off by default.

The action defaults to searching for a dependency file (

or

pyproject.toml

for pip,

Pipfile.lock

for pipenv or

poetry.lock

for poetry) in the repository, and uses its hash as a part of the cache key. Input

cache-dependency-path

is used for cases when multiple dependency files are used, they are located in different subdirectories or different files for the hash that want to be used.

• For
  pip
  , the action will cache the global cache directory
• For
  pipenv
  , the action will cache virtualenv directory
• For
  poetry
  , the action will cache virtualenv directories -- one for each poetry project found

Caching pip dependencies:

Note: Restored cache will not be used if the requirements.txt file is not updated for a long time and a newer version of the dependency is available which can lead to an increase in total build time.

The requirements file format allows for specifying dependency versions using logical operators (for example chardet>=3.0.4) or specifying dependencies without any versions. In this case the pip install -r requirements.txt command will always try to install the latest available package version. To be sure that the cache will be used, please stick to a specific dependency version and update it manually if necessary.

The

setup-python

action does not handle authentication for pip when installing packages from private repositories. For help, refer pip’s VCS support documentation or visit the pip repository.

See examples of using

and

cache-dependency-path

for

pipenv

and

poetry

in the section: Caching packages of the Advanced usage guide.

Advanced usage

• Using the python-version input
• Using the python-version-file input
• Check latest version
• Caching packages
• Outputs and environment variables
• Available versions of Python, PyPy and GraalPy
• Hosted tool cache
• Using
  setup-python
  with a self-hosted runner
• Using
  setup-python
  on GHES
• Allow pre-releases
• Using the pip-version input
• Using the pip-install input

Recommended permissions

When using the

action in your GitHub Actions workflow, it is recommended to set the following permissions to ensure proper functionality:

License

The scripts and documentation in this project are released under the MIT License.

Contributions

Contributions are welcome! See our Contributor's Guide.