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# setup-beam [![GitHub Actions][action-img]][action] [![GitHub Actions][ubuntu-img]][ubuntu] [![GitHub Actions][windows-img]][windows]

[action]: https://github.com/erlef/setup-beam
[action-img]: https://github.com/erlef/setup-beam/workflows/action/badge.svg
[ubuntu]: https://github.com/erlef/setup-beam
[ubuntu-img]: https://github.com/erlef/setup-beam/workflows/ubuntu/badge.svg
[windows]: https://github.com/erlef/setup-beam
[windows-img]: https://github.com/erlef/setup-beam/workflows/windows/badge.svg

This action sets up an Erlang/OTP environment for use in a GitHub Actions
workflow by:

- installing Erlang/OTP
- optionally, installing Elixir
- optionally, installing Gleam
- optionally, installing `rebar3`
- optionally, installing `hex`
- optionally, having
  [problem matchers](https://github.com/actions/toolkit/blob/main/docs/problem-matchers.md) show
  warnings and errors on pull requests

**Note**: currently, this action only supports Actions' `ubuntu-` and `windows-` runtimes.

## Usage

See [action.yml](action.yml) for the action's specification.

**Note**: the Erlang/OTP release version specification is [relatively
complex](http://erlang.org/doc/system_principles/versions.html#version-scheme).
For best results, we recommend specifying exact
versions, and setting option `version-type` to `strict`.
However, values like `22.x`, or even `>22`, are also accepted, and we attempt to resolve them
according to semantic versioning rules. This implicitly means `version-type` is `loose`,
which is also the default value for this option.

Additionally, it is recommended that one specifies versions
using YAML strings, as these examples do, so that numbers like `23.0` don't
end up being parsed as `23`, which is not equivalent.

For pre-release versions, such as `v1.11.0-rc.0`, use the full version
specifier (`v1.11.0-rc.0`) and set option `version-type` to `strict`. Pre-release versions are
opt-in, so `1.11.x` will not match a pre-release.

### Compatibility between Operating System and Erlang/OTP

This list presents the known working version combos between the target operating system
and Erlang/OTP.

| Operating system | Erlang/OTP | Status
|-                 |-           |-
| ubuntu-18.04     | 17 - 24    | ✅
| ubuntu-20.04     | 20 - 24    | ✅
| windows-2019     | 21* - 24   | ✅

**Note** *: prior to 23, Windows builds are only available for minor versions, e.g. 21.0, 21.3, 22.0, etc.

### Self-hosted runners

Self-hosted runners need to set env. variable `ImageOS` to one of the following, since the action
uses that to download assets:

| ImageOS  | Operating system
|-         |-
| ubuntu18 | ubuntu-18.04
| ubuntu20 | ubuntu-20.04
| win19    | windows-2019

as per the following example:

```yaml
...

jobs:
  test:
    runs-on: self-hosted
    env:
      ImageOS: ubuntu20 # equivalent to runs-on ubuntu-20.04
    steps:
      - uses: actions/checkout@v2
      - uses: erlef/setup-beam@v1
        ...
```

### Example (Erlang/OTP + Elixir, on Ubuntu)

```yaml
# create this in .github/workflows/ci.yml
on: push

jobs:
  test:
    runs-on: ubuntu-latest
    name: OTP ${{matrix.otp}} / Elixir ${{matrix.elixir}}
    strategy:
      matrix:
        otp: ['20.3', '21.3', '22.2']
        elixir: ['1.8.2', '1.9.4']
    steps:
      - uses: actions/checkout@v2
      - uses: erlef/setup-beam@v1
        with:
          otp-version: ${{matrix.otp}}
          elixir-version: ${{matrix.elixir}}
      - run: mix deps.get
      - run: mix test
```

### Example (Erlang/OTP + `rebar3`, on Ubuntu)

```yaml
# create this in .github/workflows/ci.yml
on: push

jobs:
  test:
    runs-on: ubuntu-latest
    name: Erlang/OTP ${{matrix.otp}} / rebar3 ${{matrix.rebar3}}
    strategy:
      matrix:
        otp: ['20.3', '21.3', '22.2']
        rebar3: ['3.14.1', '3.14.3']
    steps:
      - uses: actions/checkout@v2
      - uses: erlef/setup-beam@v1
        with:
          otp-version: ${{matrix.otp}}
          rebar3-version: ${{matrix.rebar3}}
      - run: rebar3 ct
```

### Example (Erlang/OTP + `rebar3`, on Windows)

```yaml
# create this in .github/workflows/ci.yml
on: push

jobs:
  test:
    runs-on: windows-2019
    steps:
      - uses: actions/checkout@v2
      - uses: erlef/setup-beam@v1
        with:
          otp-version: '24'
          rebar3-version: '3.16.1'
      - run: rebar3 ct
```

### Example (Gleam + `rebar3`, on Ubuntu)

```yaml
# create this in .github/workflows/ci.yml
on: push

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - uses: erlef/setup-beam@v1
        with:
          otp-version: '24'
          gleam-version: '0.16'
          rebar3-version: '3.16'
      - run: rebar3 ct
```

## Elixir Problem Matchers

The Elixir Problem Matchers in this repository are adapted from
[here](https://github.com/fr1zle/vscode-elixir/blob/45eddb589acd7ac98e0c7305d1c2b24668ca709a/package.json#L70-L118).
See [MATCHER_NOTICE](MATCHER_NOTICE.md) for license details.

## Action versioning

`setup-beam` has three version paths, described below, for example version `1.8.0`:

- `@v1`: the latest in the `1.y.z` series (this tag is movable),
- `@v1.8`: the latest in the `1.8.z` series (this tag is movable),
- `@v1.8.0`: release `1.8.0` (this tag is not movable).

To prevent issues in CI (unless you're OK with potential incompatibility between versions - we
make real a effort to not introduce those without bumping major) we suggest you to use `@vx.y.z`,
whenever possible.

## License

The scripts and documentation in this project are released under the [MIT license](LICENSE.md).

## Contributing

Check out [this doc](CONTRIBUTING.md).

## Current Status

This action is in active development.