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We created prefix-dev/setup-pixi to facilitate using pixi in CI.

Usage#

- uses: prefix-dev/setup-pixi@v0.6.0
  with:
    pixi-version: v0.20.0
    cache: true
    auth-host: prefix.dev
    auth-token: ${{ secrets.PREFIX_DEV_TOKEN }}
- run: pixi run test

Pin your action versions

Since pixi is not yet stable, the API of this action may change between minor versions. Please pin the versions of this action to a specific version (i.e., prefix-dev/setup-pixi@v0.6.0) to avoid breaking changes. You can automatically update the version of this action by using Dependabot.

Put the following in your .github/dependabot.yml file to enable Dependabot for your GitHub Actions:

.github/dependabot.yml
version: 2
updates:
  - package-ecosystem: github-actions
    directory: /
    schedule:
      interval: monthly # (1)!
    groups:
      dependencies:
        patterns:
          - "*"
  1. or daily, weekly

Features#

To see all available input arguments, see the action.yml file in setup-pixi. The most important features are described below.

Caching#

The action supports caching of the pixi environment. By default, caching is enabled if a pixi.lock file is present. It will then use the pixi.lock file to generate a hash of the environment and cache it. If the cache is hit, the action will skip the installation and use the cached environment. You can specify the behavior by setting the cache input argument.

Customize your cache key

If you need to customize your cache-key, you can use the cache-key input argument. This will be the prefix of the cache key. The full cache key will be <cache-key><conda-arch>-<hash>.

Only save caches on main

In order to not exceed the 10 GB cache size limit as fast, you might want to restrict when the cache is saved. This can be done by setting the cache-write argument.

- uses: prefix-dev/setup-pixi@v0.5.1
  with:
    cache: true
    cache-write: ${{ github.event_name == 'push' && github.ref_name == 'main' }}

Multiple environments#

With pixi, you can create multiple environments for different requirements. You can also specify which environment(s) you want to install by setting the environments input argument. This will install all environments that are specified and cache them.

[project]
name = "my-package"
channels = ["conda-forge"]
platforms = ["linux-64"]

[dependencies]
python = ">=3.11"
pip = "*"
polars = ">=0.14.24,<0.21"

[feature.py311.dependencies]
python = "3.11.*"
[feature.py312.dependencies]
python = "3.12.*"

[environments]
py311 = ["py311"]
py312 = ["py312"]

Multiple environments using a matrix#

The following example will install the py311 and py312 environments in different jobs.

test:
  runs-on: ubuntu-latest
  strategy:
    matrix:
      environment: [py311, py312]
  steps:
  - uses: actions/checkout@v4
  - uses: prefix-dev/setup-pixi@v0.6.0
    with:
      environments: ${{ matrix.environment }}

Install multiple environments in one job#

The following example will install both the py311 and the py312 environment on the runner.

- uses: prefix-dev/setup-pixi@v0.6.0
  with:
    environments: >- # (1)!
      py311
      py312
- run: |
  pixi run -e py311 test
  pixi run -e py312 test

  1. separated by spaces, equivalent to

    environments: py311 py312

Caching behavior if you don't specify environments

If you don't specify any environment, the default environment will be installed and cached, even if you use other environments.

Authentication#

There are currently three ways to authenticate with pixi:

  • using a token
  • using a username and password
  • using a conda-token

For more information, see Authentication.

Handle secrets with care

Please only store sensitive information using GitHub secrets. Do not store them in your repository. When your sensitive information is stored in a GitHub secret, you can access it using the ${{ secrets.SECRET_NAME }} syntax. These secrets will always be masked in the logs.

Token#

Specify the token using the auth-token input argument. This form of authentication (bearer token in the request headers) is mainly used at prefix.dev.

- uses: prefix-dev/setup-pixi@v0.6.0
  with:
    auth-host: prefix.dev
    auth-token: ${{ secrets.PREFIX_DEV_TOKEN }}

Username and password#

Specify the username and password using the auth-username and auth-password input arguments. This form of authentication (HTTP Basic Auth) is used in some enterprise environments with artifactory for example.

- uses: prefix-dev/setup-pixi@v0.6.0
  with:
    auth-host: custom-artifactory.com
    auth-username: ${{ secrets.PIXI_USERNAME }}
    auth-password: ${{ secrets.PIXI_PASSWORD }}

Conda-token#

Specify the conda-token using the conda-token input argument. This form of authentication (token is encoded in URL: https://my-quetz-instance.com/t/<token>/get/custom-channel) is used at anaconda.org or with quetz instances.

- uses: prefix-dev/setup-pixi@v0.6.0
  with:
    auth-host: anaconda.org # (1)!
    conda-token: ${{ secrets.CONDA_TOKEN }}
  1. or my-quetz-instance.com

Custom shell wrapper#

setup-pixi allows you to run command inside of the pixi environment by specifying a custom shell wrapper with shell: pixi run bash -e {0}. This can be useful if you want to run commands inside of the pixi environment, but don't want to use the pixi run command for each command.

- run: | # (1)!
    python --version
    pip install --no-deps -e .
  shell: pixi run bash -e {0}
  1. everything here will be run inside of the pixi environment

You can even run Python scripts like this:

- run: | # (1)!
    import my_package
    print("Hello world!")
  shell: pixi run python {0}
  1. everything here will be run inside of the pixi environment

If you want to use PowerShell, you need to specify -Command as well.

- run: | # (1)!
    python --version | Select-String "3.11"
  shell: pixi run pwsh -Command {0} # pwsh works on all platforms
  1. everything here will be run inside of the pixi environment

How does it work under the hood?

Under the hood, the shell: xyz {0} option is implemented by creating a temporary script file and calling xyz with that script file as an argument. This file does not have the executable bit set, so you cannot use shell: pixi run {0} directly but instead have to use shell: pixi run bash {0}. There are some custom shells provided by GitHub that have slightly different behavior, see jobs.<job_id>.steps[*].shell in the documentation. See the official documentation and ADR 0277 for more information about how the shell: input works in GitHub Actions.

--frozen and --locked#

You can specify whether setup-pixi should run pixi install --frozen or pixi install --locked depending on the frozen or the locked input argument. See the official documentation for more information about the --frozen and --locked flags.

- uses: prefix-dev/setup-pixi@v0.6.0
  with:
    locked: true
    # or
    frozen: true

If you don't specify anything, the default behavior is to run pixi install --locked if a pixi.lock file is present and pixi install otherwise.

Debugging#

There are two types of debug logging that you can enable.

Debug logging of the action#

The first one is the debug logging of the action itself. This can be enabled by for the action by re-running the action in debug mode:

Re-run in debug mode Re-run in debug mode

Debug logging documentation

For more information about debug logging in GitHub Actions, see the official documentation.

Debug logging of pixi#

The second type is the debug logging of the pixi executable. This can be specified by setting the log-level input.

- uses: prefix-dev/setup-pixi@v0.6.0
  with:
    log-level: vvv # (1)!
  1. One of q, default, v, vv, or vvv.

If nothing is specified, log-level will default to default or vv depending on if debug logging is enabled for the action.

Self-hosted runners#

On self-hosted runners, it may happen that some files are persisted between jobs. This can lead to problems or secrets getting leaked between job runs. To avoid this, you can use the post-cleanup input to specify the post cleanup behavior of the action (i.e., what happens after all your commands have been executed).

If you set post-cleanup to true, the action will delete the following files:

  • .pixi environment
  • the pixi binary
  • the rattler cache
  • other rattler files in ~/.rattler

If nothing is specified, post-cleanup will default to true.

On self-hosted runners, you also might want to alter the default pixi install location to a temporary location. You can use pixi-bin-path: ${{ runner.temp }}/bin/pixi to do this.

- uses: prefix-dev/setup-pixi@v0.6.0
  with:
    post-cleanup: true
    pixi-bin-path: ${{ runner.temp }}/bin/pixi # (1)!
  1. ${{ runner.temp }}\Scripts\pixi.exe on Windows

You can also use a preinstalled local version of pixi on the runner by not setting any of the pixi-version, pixi-url or pixi-bin-path inputs. This action will then try to find a local version of pixi in the runner's PATH.

Using the pyproject.toml as a manifest file for pixi.#

setup-pixi will automatically pick up the pyproject.toml if it contains a [tool.pixi.project] section and no pixi.toml. This can be overwritten by setting the manifest-path input argument.

- uses: prefix-dev/setup-pixi@v0.6.0
  with:
    manifest-path: pyproject.toml

More examples#

If you want to see more examples, you can take a look at the GitHub Workflows of the setup-pixi repository.