setup-dune: a GitHub Action to install Dune and optionally build a project with Dune package management

How to use it

Create a .github/workflows/dune.yml file with something like:

name: Build and test

on: [push, pull_request]

jobs:
  build:
    strategy:
      matrix:
        runs-on: [ ubuntu-latest, macos-latest ]
    runs-on: ${{ matrix.runs-on }}

    steps:
      - name: Checkout code
        uses: actions/checkout@v6
      - name: Use dune
        uses: ocaml-dune/setup-dune@v2

Inputs

Key	Meaning	Default value
version	version of dune to use	nightly
steps	which steps should be run	all
directory	where is the project that should be built and tested	current directory (.)
workspace	argument for the --workspace option (relative to directory)	empty (Dune’s default)
display	argument for the --display option	empty (Dune’s default)

Details

The version can have the following special values:

• nightly for the latest nightly release: this is the default at the moment since dune package management is still moving fast and targeted at early adopters.
• latest for the latest stable release of dune: for CI systems that want more stable use of dune package management.

steps should be either a space-separated list of the steps to perform or one of two special values.

• The steps are named: install-dune, enable-pkg, lazy-update-depexts, install-gpatch, install-depexts, build-deps, build, and runtest.

  • enable-pkg enables Dune package management by creating a configuration containing (pkg enabled) (for Dune 3.21 or later).
  • lazy-update-depexts, when present, will trigger a brew update or apt-get update just before any other external dependency installation (during install-gpatch on macOS or on install-depexts on all OSes); if no such installation is required, the update is skipped (hence the lazy).

  The other steps should be pretty self-explanatory.

• If steps is given the all value, all those steps are performed.

• If steps is given the empty value, only the install-dune step is performed.

It can be useful to set an explicit value for steps for instance when:

• your project doesn’t require gpatch, as updating brew and installing gpatch takes some time already,
• you have a repository with more than one project and you want to trigger setup-dune more than once but still install dune and run {apt,brew} update (if needed) only the first time.

Outputs

Key	Meaning
dune-cache-hit	whether the Dune cache was found in the GitHub Action cache

Contributions

Contributions are most welcome!

• File issues to report bugs or feature requests.
• Contribute code or documentation.

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This project has been created and is maintained by Tarides.