STATUS: STABLE
Set up an OCaml and opam environment in GitHub Actions and add to PATH.
Consult the Hello World OCaml Action that uses Dune and opam to build a simple library.
It's possible to feed different values to the input depending on the platform of the runner. The syntax of GitHub's workflows is flexible enough to offer several methods to do this.
name: Builds, tests & co
on:
- push
- pull_request
permissions: read-all
jobs:
build:
strategy:
fail-fast: false
matrix:
os:
- ubuntu-latest
- macos-latest
- windows-latest
runs-on: ${{ matrix.os }}
steps:
- name: Checkout tree
uses: actions/checkout@v4
- name: Set-up OCaml
uses: ocaml/setup-ocaml@v3
with:
ocaml-compiler: 5
- run: opam install . --deps-only --with-test
- run: opam exec -- dune build
- run: opam exec -- dune runtestWhen using GitHub-hosted runners, specifying compiler version 4 or 5 should work across all platforms and architectures. However, there are exceptions, as shown below. If you need to test with specific versions, please choose the appropriate version for your runtime environment.
| Version | Ubuntu | macOS | Windows |
|---|---|---|---|
| >= 4.13 | ✅ | ✅ | ✅ |
| >= 4.02 & <= 4.12 | ✅ | ✅ | ❌ |
| <= 4.01 | ✅ | ✅ | ❌ |
| Version | Ubuntu | macOS | Windows |
|---|---|---|---|
| >= 4.12 | ✅ | ✅ | ❌ |
| = 4.11 | ✅ | ❌ | ❌ |
| = 4.10 | ✅ | ✅ | ❌ |
| >= 4.02 & <= 4.09 | ✅ | ❌ | ❌ |
| <= 4.01 | ❌ | ❌ | ❌ |
The actions are downloaded and run from the GitHub graph of repositories. The workflow references an action using a ref.
Note
Binding to a major version is the latest of that major version (e.g. v3 = 3.*) Major versions should guarantee compatibility. A major version can add net new capabilities but should not break existing input compatibility or break existing workflows.
- name: Set-up OCaml ${{ matrix.ocaml-compiler }}
uses: ocaml/setup-ocaml@v3
# ^^^
with:
ocaml-compiler: ${{ matrix.ocaml-compiler }}Warning
Do not reference master since that is the latest code and can be carrying breaking changes of the next major version.
Major version binding allows you to take advantage of bug fixes, critical functionality and security fixes. The master branch has the latest code and is unstable to bind to since changes get committed to the master and released by creating a tag.
steps:
# Reference the major version of a release (most recommended)
- uses: ocaml/setup-ocaml@v3
# Reference a specific commit (most strict)
- uses: ocaml/setup-ocaml@<SHA>
# Reference a semver version of a release (not recommended)
- uses: ocaml/setup-ocaml@v3.0.0
# Reference a branch (most dangerous - do not do this)
- uses: ocaml/setup-ocaml@master| Name | Required | Description | Type | Default |
|---|---|---|---|---|
ocaml-compiler |
Yes | The OCaml compiler packages to initialise. Consult the supported version syntax section. | string | |
opam-repositories |
No | The name and URL pair of the repository to fetch the packages from. | string | default: https://github.com/ocaml/opam-repository.git |
opam-pin |
No | Enable the automation feature for opam pin. | bool | true |
opam-local-packages |
No | The local packages to be used by opam-pin. Consult the @actions/glob documentation package for supported patterns. |
string | *.opam |
opam-disable-sandboxing |
No | Disable the opam sandboxing feature. | bool | false |
dune-cache |
No | Enable the dune cache feature. This feature requires dune 2.8.5 or later on the Windows runners. | bool | false |
cache-prefix |
No | The prefix of the cache keys. | string | v1 |
allow-prerelease-opam |
No | Allow to use a pre-release version of opam. | bool | false |
The ocaml-compiler input supports the Semantic Versioning Specification, for more detailed examples please refer to the documentation.
Note
With the naughty exception of 4.02.2, point releases are meant to be strictly compatible, so once we (OCaml dev team) release a new point release, upgrading should be a no-brainer.
Examples:
- Exact package name:
ocaml-base-compiler.5.2.0 - Combine multiple packages:
ocaml-variants.5.2.0+options,ocaml-option-flambda,ocaml-option-musl,ocaml-option-static - Major versions:
4,5 - Minor versions:
4.08,4.14,5.2,5.2.x - More specific versions:
~4.02.2,5.1.0
Consult the examples page for more complex patterns.
STATUS: EXPERIMENTAL
Note
All extends are recommended to be used in separate jobs run on ubuntu-latest.
Consult the Configuring Dependabot version updates page and set .github/dependabot.yml as described below to allow Dependabot to update the actions automatically.
version: 2
updates:
- package-ecosystem: github-actions
directory: /
schedule:
interval: weeklyNote
Renovate is also available for free as a third-party tool, which is much more flexible than Dependabot - depending on the project and your preferences. If you just want to automate GitHub Actions updates, Dependabot is good enough.
This action aims to provide an OS-neutral interface to opam, and so will not add features that only work on one operating system. It will also track the latest stable release of opam.
Please feel free to post to the discuss.ocaml.org forum with any questions you have about this action.
Previous discussions include: