This action downloads a prebuilt ruby and adds it to the PATH.

It is very efficient and takes about 5 seconds to download, extract and add the given Ruby to the PATH. No extra packages need to be installed.

This action currently supports these versions of MRI, JRuby and TruffleRuby:

Note that Ruby 2.3 and the OpenSSL version it needs (1.0.2) are both end-of-life, which means Ruby 2.3 is unmaintained and considered insecure. On Windows, Ruby 2.4 uses OpenSSL 1.0.2, which is no longer maintained.

The action works for all GitHub-hosted runners.

Rubinius is only available on ubuntu-latest.

The prebuilt rubies are generated by eregon/ruby-install-builder and on Windows by RubyInstaller2.
The full list of available Ruby versions can be seen in ruby-install-builder-versions.js for Ubuntu and macOS and in windows-versions.js for Windows.

name: My workflow
on: [push]
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
    - uses: eregon/use-ruby-action@v1
      with:
        ruby-version: 2.6
    - run: ruby -v

This matrix tests all stable releases of MRI, JRuby and TruffleRuby on Ubuntu and macOS.

name: My workflow
on: [push]
jobs:
  test:
    strategy:
      fail-fast: false
      matrix:
        os: [ ubuntu-latest, macos-latest ]
        ruby: [ 2.4, 2.5, 2.6, 2.7, jruby, truffleruby ]
    runs-on: ${{ matrix.os }}
    steps:
    - uses: actions/checkout@v2
    - uses: eregon/use-ruby-action@v1
      with:
        ruby-version: ${{ matrix.ruby }}
    - run: ruby -v

• engine-version like ruby-2.6.5 and truffleruby-19.3.0
• short version like 2.6, automatically using the latest release matching that version (2.6.5)
• version only like 2.6.5, assumes MRI for the engine
• engine only like truffleruby, uses the latest stable release of that implementation
• .ruby-version (also the default value) reads from the project's .ruby-version file

Currently, Bundler is guaranteed to be installed for all versions. If the Ruby ships with Bundler (Ruby >= 2.6), that version is used. Otherwise (Ruby < 2.6), Bundler 1 is installed when that Ruby was built.

You can cache the installed gems with these two steps:

    - uses: actions/cache@v1
      with:
        path: vendor/bundle
        key: bundle-use-ruby-${{ matrix.os }}-${{ matrix.ruby }}-${{ hashFiles('**/Gemfile.lock') }}
        restore-keys: |
          bundle-use-ruby-${{ matrix.os }}-${{ matrix.ruby }}-
    - name: bundle install
      run: |
        bundle config path vendor/bundle
        bundle install --jobs 4 --retry 3

When using a single job with a Ruby version, replace ${{ matrix.ruby }} with the Ruby version.
When using .ruby-version, replace ${{ matrix.ruby }} with ${{ hashFiles('.ruby-version') }}.

This uses the cache action. The code above is a more complete version of the Ruby - Bundler example. Make sure to include use-ruby in the key to avoid conflicting with previous caches.

• This action currently only works with GitHub-hosted runners, not private runners.

This action follows semantic versioning with a moving v1 branch. This follows the recommendations of GitHub Actions.

Most of the Windows logic is from https://github.com/MSP-Greg/actions-ruby by MSP-Greg. Many thanks to MSP-Greg and Lars Kanis for the help with Ruby Installer.