> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/open-source/use-harness-open-source/pipelines-1/samples/erlang.md).

# Erlang

This guide covers configuring continuous integration pipelines for Erlang projects.

## Build and Test <a href="#build-and-test" id="build-and-test"></a>

In the below example we demonstrate a pipeline that executes `rebar` commands. These commands are executed inside the Erlang Docker container, downloaded at runtime from DockerHub.

```yaml
kind: pipeline
spec:
  stages:
  - type: ci
    spec:
      steps:
      - name: test
        type: run
        spec:
          container: erlang:21
          script: |-
            rebar get-deps
            rebar compile
            rebar skip_deps=true eunit
```

Please note that you can use any Docker image in your pipeline from any Docker registry. You can use the official Erlang [images](https://hub.docker.com/r/_/erlang/), or your can bring your own.

## Test Multiple Versions <a href="#test-multiple-versions" id="test-multiple-versions"></a>

You can configure multiple, containerized steps to test against multiple versions of Erlang.

```yaml
kind: pipeline
spec:
  stages:
  - type: ci
    spec:
      steps:
      - name: test 21
        type: run
        spec:
          container: erlang:21
          script: |-
            rebar get-deps
            rebar compile
            rebar skip_deps=true eunit

      - name: test 20
        type: run
        spec:
          container: erlang:20
          script: |-
            rebar get-deps
            rebar compile
            rebar skip_deps=true eunit
```