How to set up Continuous Integration with Package Management

For many projects published it can be useful to set up a continuous integration (CI) system. This allows to check whether the code builds on other computers, the tests pass and helps to assess contributions from other people.

There are numerous CI systems available. In this document we will be using GitHub Actions, as it is integrated in the commonly used GitHub platform and free to use.

What are Actions

Projects on GitHub can set up Actions, that is workflows defined in YAML files. These definitions are placed in the .github/workflows/ folder in the Git repository.

These workflows consist of the execution of a sequence of actions, like running shell commands. It is also possible to use pre-defined actions or even user-submitted functionality.

setup-dune

setup-dune is one such custom action maintained by the OCaml community to help with setting up builds with Dune.

It installs Dune in the GitHub runner environment and will attempt to build the source code using Dune package management.

.github/workflow/ci.yaml

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: Build project with dune
        uses: ocaml-dune/setup-dune@v2

We define a job called build, which will be run on Ubuntu and macOS (a list of possible options can be found in the GitHub documentation).

This job first checks out the projects’ source code using an action maintained by GitHub and then uses the setup-dune action to install Dune on the system and build the project.

setup-dune will enable package management by default and attempt to build the project with the current nightly version of Dune.

Additional configuration options can be found in the documentation of setup-dune, which includes picking a fixed version of Dune, picking a specific OCaml compiler etc.

This configuration file has to be added to the repository and pushed to GitHub. Some configuration to enable actions in the repository might be required, check out the GitHub documentation on repository settings related to actions.

Once set up, this action will be run on the commit of every push to every branch as well as on every pull request. The results of running the actions are visible as a colored dot next to the relevant commits that were processed by CI.

See also

GitHub Actions documentation for information about the configuration format and usual workflows.

GitHub Actions marketplace for a list of published actions.