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Building and testing Python |
You can create a continuous integration (CI) workflow to build and test your Python project. |
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tutorial |
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Build & test Python |
{% data reusables.actions.enterprise-github-hosted-runners %}
This guide shows you how to build, test, and publish a Python package.
{% data variables.product.prodname_dotcom %}-hosted runners have a tools cache with pre-installed software, which includes Python and PyPy. You don't have to install anything! For a full list of up-to-date software and the pre-installed versions of Python and PyPy, see AUTOTITLE.
You should be familiar with YAML and the syntax for {% data variables.product.prodname_actions %}. For more information, see AUTOTITLE.
We recommend that you have a basic understanding of Python, and pip. For more information, see:
{% data reusables.actions.enterprise-setup-prereq %}
{% data reusables.actions.workflow-templates-get-started %}
{% data variables.product.prodname_dotcom %} provides a workflow template for Python that should work if your repository already contains at least one .py
file. The subsequent sections of this guide give examples of how you can customize this workflow template.
{% data reusables.repositories.navigate-to-repo %} {% data reusables.repositories.actions-tab %} {% data reusables.actions.new-starter-workflow %}
- The "Choose a workflow" page shows a selection of recommended workflow templates. Search for "Python application".
- On the "Python application" workflow, click Configure.
{%- ifversion ghes %}
If you don't find the "Python application" workflow template, copy the following workflow code to a new file called python-app.yml
in the .github/workflows
directory of your repository.
name: Python application
on:
push:
branches: [ "main" ]
pull_request:
branches: [ "main" ]
permissions:
contents: read
jobs:
build:
runs-on: ubuntu-latest
steps:
- uses: {% data reusables.actions.action-checkout %}
- name: Set up Python 3.13
uses: {% data reusables.actions.action-setup-python %}
with:
python-version: "3.13"
- name: Install dependencies
run: |
python -m pip install --upgrade pip
pip install ruff pytest
if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
- name: Lint and format Python code with ruff
run: |
# Lint with the default set of ruff rules with GitHub Annotations
ruff check --format=github --target-version=py39
# Verify the code is properly formatted
ruff format --diff --target-version=py39
- name: Test with pytest
run: |
pytest
{%- endif %}
- Edit the workflow as required. For example, change the Python version.
- Click Commit changes.
{% ifversion fpt or ghec %}
The python-app.yml
workflow file is added to the .github/workflows
directory of your repository.
{% endif %}
To use a pre-installed version of Python or PyPy on a {% data variables.product.prodname_dotcom %}-hosted runner, use the setup-python
action. This action finds a specific version of Python or PyPy from the tools cache on each runner and adds the necessary binaries to PATH
, which persists for the rest of the job. If a specific version of Python is not pre-installed in the tools cache, the setup-python
action will download and set up the appropriate version from the python-versions
repository.
Using the setup-python
action is the recommended way of using Python with {% data variables.product.prodname_actions %} because it ensures consistent behavior across different runners and different versions of Python. If you are using a self-hosted runner, you must install Python and add it to PATH
. For more information, see the setup-python
action.
The table below describes the locations for the tools cache in each {% data variables.product.prodname_dotcom %}-hosted runner.
{% rowheaders %}
Ubuntu | Mac | Windows | |
---|---|---|---|
Tool Cache Directory | /opt/hostedtoolcache/* |
/Users/runner/hostedtoolcache/* |
C:\hostedtoolcache\windows\* |
Python Tool Cache | /opt/hostedtoolcache/Python/* |
/Users/runner/hostedtoolcache/Python/* |
C:\hostedtoolcache\windows\Python\* |
PyPy Tool Cache | /opt/hostedtoolcache/PyPy/* |
/Users/runner/hostedtoolcache/PyPy/* |
C:\hostedtoolcache\windows\PyPy\* |
{% endrowheaders %}
If you are using a self-hosted runner, you can configure the runner to use the setup-python
action to manage your dependencies. For more information, see using setup-python with a self-hosted runner in the setup-python
README.
{% data variables.product.prodname_dotcom %} supports semantic versioning syntax. For more information, see Using semantic versioning and the Semantic versioning specification.
The following example uses a matrix for the job to set up multiple Python versions. For more information, see AUTOTITLE.
name: Python package
on: [push]
jobs:
build:
runs-on: ubuntu-latest
strategy:
matrix:
python-version: ["pypy3.10", "3.9", "3.10", "3.11", "3.12", "3.13"]
steps:
- uses: {% data reusables.actions.action-checkout %}
- name: Set up Python {% raw %}${{ matrix.python-version }}{% endraw %}
uses: {% data reusables.actions.action-setup-python %}
with:
python-version: {% raw %}${{ matrix.python-version }}{% endraw %}
# You can test your matrix by printing the current Python version
- name: Display Python version
run: python -c "import sys; print(sys.version)"
You can configure a specific version of Python. For example, 3.12. Alternatively, you can use semantic version syntax to get the latest minor release. This example uses the latest minor release of Python 3.
name: Python package
on: [push]
jobs:
build:
runs-on: ubuntu-latest
steps:
- uses: {% data reusables.actions.action-checkout %}
- name: Set up Python
# This is the version of the action for setting up Python, not the Python version.
uses: {% data reusables.actions.action-setup-python %}
with:
# Semantic version range syntax or exact version of a Python version
python-version: '3.x'
# Optional - x64 or x86 architecture, defaults to x64
architecture: 'x64'
# You can test your matrix by printing the current Python version
- name: Display Python version
run: python -c "import sys; print(sys.version)"
If you specify a version of Python that is not available, setup-python
fails with an error such as: ##[error]Version 3.7 with arch x64 not found
. The error message includes the available versions.
You can also use the exclude
keyword in your workflow if there is a configuration of Python that you do not wish to run. For more information, see AUTOTITLE.
name: Python package
on: [push]
jobs:
build:
runs-on: {% raw %}${{ matrix.os }}{% endraw %}
strategy:
matrix:
os: [ubuntu-latest, macos-latest, windows-latest]
python-version: ["3.9", "3.11", "3.13", "pypy3.10"]
exclude:
- os: macos-latest
python-version: "3.11"
- os: windows-latest
python-version: "3.11"
We recommend using setup-python
to configure the version of Python used in your workflows because it helps make your dependencies explicit. If you don't use setup-python
, the default version of Python set in PATH
is used in any shell when you call python
. The default version of Python varies between {% data variables.product.prodname_dotcom %}-hosted runners, which may cause unexpected changes or use an older version than expected.
{% data variables.product.prodname_dotcom %}-hosted runner | Description |
---|---|
Ubuntu | Ubuntu runners have multiple versions of system Python installed under /usr/bin/python and /usr/bin/python3 . The Python versions that come packaged with Ubuntu are in addition to the versions that {% data variables.product.prodname_dotcom %} installs in the tools cache. |
Windows | Excluding the versions of Python that are in the tools cache, Windows does not ship with an equivalent version of system Python. To maintain consistent behavior with other runners and to allow Python to be used out-of-the-box without the setup-python action, {% data variables.product.prodname_dotcom %} adds a few versions from the tools cache to PATH . |
macOS | The macOS runners have more than one version of system Python installed, in addition to the versions that are part of the tools cache. The system Python versions are located in the /usr/local/Cellar/python/* directory. |
{% data variables.product.prodname_dotcom %}-hosted runners have the pip package manager installed. You can use pip to install dependencies from the PyPI package registry before building and testing your code. For example, the YAML below installs or upgrades the pip
package installer and the setuptools
and wheel
packages.
You can also cache dependencies to speed up your workflow. For more information, see AUTOTITLE.
steps:
- uses: {% data reusables.actions.action-checkout %}
- name: Set up Python
uses: {% data reusables.actions.action-setup-python %}
with:
python-version: '3.x'
- name: Install dependencies
run: python -m pip install --upgrade pip setuptools wheel
After you update pip
, a typical next step is to install dependencies from requirements.txt
. For more information, see pip.
steps:
- uses: {% data reusables.actions.action-checkout %}
- name: Set up Python
uses: {% data reusables.actions.action-setup-python %}
with:
python-version: '3.x'
- name: Install dependencies
run: |
python -m pip install --upgrade pip
pip install -r requirements.txt
You can cache and restore the dependencies using the setup-python
action.
The following example caches dependencies for pip.
steps:
- uses: {% data reusables.actions.action-checkout %}
- uses: {% data reusables.actions.action-setup-python %}
with:
python-version: '3.12'
cache: 'pip'
- run: pip install -r requirements.txt
- run: pip test
By default, the setup-python
action searches for the dependency file (requirements.txt
for pip, Pipfile.lock
for pipenv or poetry.lock
for poetry) in the whole repository. For more information, see Caching packages dependencies in the setup-python
README.
If you have a custom requirement or need finer controls for caching, you can use the cache
action. Pip caches dependencies in different locations, depending on the operating system of the runner. The path you'll need to cache may differ from the Ubuntu example above, depending on the operating system you use. For more information, see Python caching examples in the cache
action repository.
You can use the same commands that you use locally to build and test your code.
This example installs or upgrades pytest
and pytest-cov
. Tests are then run and output in JUnit format while code coverage results are output in Cobertura. For more information, see JUnit and Cobertura.
steps:
- uses: {% data reusables.actions.action-checkout %}
- name: Set up Python
uses: {% data reusables.actions.action-setup-python %}
with:
python-version: '3.x'
- name: Install dependencies
run: |
python -m pip install --upgrade pip
pip install -r requirements.txt
- name: Test with pytest
run: |
pip install pytest pytest-cov
pytest tests.py --doctest-modules --junitxml=junit/test-results.xml --cov=com --cov-report=xml --cov-report=html
The following example installs or upgrades ruff
and uses it to lint all files. For more information, see Ruff.
steps:
- uses: {% data reusables.actions.action-checkout %}
- name: Set up Python
uses: {% data reusables.actions.action-setup-python %}
with:
python-version: '3.x'
- name: Install the code linting and formatting tool Ruff
run: pipx install ruff
- name: Lint code with Ruff
run: ruff check --output-format=github --target-version=py39
- name: Check code formatting with Ruff
run: ruff format --diff --target-version=py39
continue-on-error: true
The formatting step has continue-on-error: true
set. This will keep the workflow from failing if the formatting step doesn't succeed. Once you've addressed all of the formatting errors, you can remove this option so the workflow will catch new issues.
With {% data variables.product.prodname_actions %}, you can run tests with tox and spread the work across multiple jobs. You'll need to invoke tox using the -e py
option to choose the version of Python in your PATH
, rather than specifying a specific version. For more information, see tox.
name: Python package
on: [push]
jobs:
build:
runs-on: ubuntu-latest
strategy:
matrix:
python: ["3.9", "3.11", "3.13"]
steps:
- uses: {% data reusables.actions.action-checkout %}
- name: Setup Python
uses: {% data reusables.actions.action-setup-python %}
with:
python-version: {% raw %}${{ matrix.python }}{% endraw %}
- name: Install tox and any other packages
run: pip install tox
- name: Run tox
# Run tox using the version of Python in `PATH`
run: tox -e py
You can upload artifacts to view after a workflow completes. For example, you may need to save log files, core dumps, test results, or screenshots. For more information, see AUTOTITLE.
The following example demonstrates how you can use the upload-artifact
action to archive test results from running pytest
. For more information, see the upload-artifact
action.
name: Python package
on: [push]
jobs:
build:
runs-on: ubuntu-latest
strategy:
matrix:
python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
steps:
- uses: {% data reusables.actions.action-checkout %}
- name: Setup Python # Set Python version
uses: {% data reusables.actions.action-setup-python %}
with:
python-version: {% raw %}${{ matrix.python-version }}{% endraw %}
# Install pip and pytest
- name: Install dependencies
run: |
python -m pip install --upgrade pip
pip install pytest
- name: Test with pytest
run: pytest tests.py --doctest-modules {% raw %}--junitxml=junit/test-results-${{ matrix.python-version }}.xml{% endraw %}
- name: Upload pytest test results
uses: {% data reusables.actions.action-upload-artifact %}
with:
name: {% raw %}pytest-results-${{ matrix.python-version }}{% endraw %}
path: {% raw %}junit/test-results-${{ matrix.python-version }}.xml{% endraw %}
# Use always() to always run this step to publish test results when there are test failures
if: {% raw %}${{ always() }}{% endraw %}
You can configure your workflow to publish your Python package to PyPI once your CI tests pass. This section demonstrates how you can use {% data variables.product.prodname_actions %} to upload your package to PyPI each time you publish a release. For more information, see AUTOTITLE.
The example workflow below uses Trusted Publishing to authenticate with PyPI, eliminating the need for a manually configured API token.
{% data reusables.actions.actions-not-certified-by-github-comment %}
{% data reusables.actions.actions-use-sha-pinning-comment %}
name: Upload Python Package
on:
release:
types: [published]
permissions:
contents: read
jobs:
release-build:
runs-on: ubuntu-latest
steps:
- uses: {% data reusables.actions.action-checkout %}
- uses: {% data reusables.actions.action-setup-python %}
with:
python-version: "3.x"
- name: Build release distributions
run: |
# NOTE: put your own distribution build steps here.
python -m pip install build
python -m build
- name: Upload distributions
uses: {% data reusables.actions.action-upload-artifact %}
with:
name: release-dists
path: dist/
pypi-publish:
runs-on: ubuntu-latest
needs:
- release-build
permissions:
# IMPORTANT: this permission is mandatory for trusted publishing
id-token: write
# Dedicated environments with protections for publishing are strongly recommended.
environment:
name: pypi
# OPTIONAL: uncomment and update to include your PyPI project URL in the deployment status:
# url: https://pypi.org/p/YOURPROJECT
steps:
- name: Retrieve release distributions
uses: {% data reusables.actions.action-download-artifact %}
with:
name: release-dists
path: dist/
- name: Publish release distributions to PyPI
uses: pypa/gh-action-pypi-publish@6f7e8d9c0b1a2c3d4e5f6a7b8c9d0e1f2a3b4c5d
{% ifversion not ghes %}
For more information about this workflow, including the PyPI settings needed, see AUTOTITLE.
{% endif %}