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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.

Compared to actions/setup-ruby, this actions supports many more versions and features.

Supported Versions

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

Interpreter Versions
ruby 1.9.3, 2.0.0, 2.1.9, 2.2, all versions from 2.3.0 until 3.2.0-preview1, head, debug, mingw, mswin
jruby -, head
truffleruby 19.3.0 - 22.1.0, head
truffleruby+graalvm 21.2.0 - 22.1.0, head

ruby-debug is the same as ruby-head but with assertions enabled (-DRUBY_DEBUG=1).
On Windows, mingw and mswin are ruby-head builds using the MSYS2/MinGW and the MSVC toolchains respectively.

Preview and RC versions of Ruby might be available too on Ubuntu and macOS (not on Windows). However, it is recommended to test against ruby-head rather than previews, as it provides more useful feedback for the Ruby core team and for upcoming changes.

Only versions published by RubyInstaller are available on Windows. Due to that, Ruby 2.2 resolves to 2.2.6 on Windows and 2.2.10 on other platforms. And Ruby 2.3 on Windows only has builds for 2.3.0, 2.3.1 and 2.3.3.

Note that Ruby ≤ 2.4 and the OpenSSL version it needs (1.0.2) are both end-of-life, which means Ruby ≤ 2.4 is unmaintained and considered insecure.

Supported Platforms

The action works on these GitHub-hosted runners virtual environments. Virtual environments not listed below are unsupported.

Operating System Recommended Other Supported Versions
Ubuntu ubuntu-latest (= ubuntu-20.04) ubuntu-18.04, ubuntu-22.04 (beta, only ruby: 3.1 - head)
macOS macos-latest (= macos-11) macos-10.15, macos-12 (beta)
Windows windows-latest (= windows-2022) windows-2019

On ubuntu-22.04 (beta), only ruby: 3.1 - head are supported, due to Ubuntu 22.04 only supporting OpenSSL 3.

The prebuilt releases are generated by ruby-builder and on Windows by RubyInstaller2. mingw and mswin builds are generated by ruby-loco. ruby-head is generated by ruby-dev-builder, jruby-head is generated by jruby-dev-builder, truffleruby-head is generated by truffleruby-dev-builder and truffleruby+graalvm is generated by graalvm-ce-dev-builds. The full list of available Ruby versions can be seen in ruby-builder-versions.json for Ubuntu and macOS and in windows-versions.json for Windows.


Single Job

name: My workflow
on: [push, pull_request]
    runs-on: ubuntu-latest
    - uses: actions/checkout@v3
    - uses: ruby/setup-ruby@v1
        ruby-version: '3.0' # Not needed with a .ruby-version file
        bundler-cache: true # runs 'bundle install' and caches installed gems automatically
    - run: bundle exec rake

Matrix of Ruby Versions

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

name: My workflow
on: [push, pull_request]
      fail-fast: false
        os: [ubuntu-latest, macos-latest]
        # Due to, we have to use quotes for '3.0'
        ruby: ['2.7', '3.0', '3.1', head, jruby, jruby-head, truffleruby, truffleruby-head]
    runs-on: ${{ matrix.os }}
    - uses: actions/checkout@v3
    - uses: ruby/setup-ruby@v1
        ruby-version: ${{ matrix.ruby }}
        bundler-cache: true # runs 'bundle install' and caches installed gems automatically
    - run: bundle exec rake

Matrix of Gemfiles

name: My workflow
on: [push, pull_request]
      fail-fast: false
        gemfile: [ rails5, rails6 ]
    runs-on: ubuntu-latest
    env: # $BUNDLE_GEMFILE must be set at the job level, so it is set for all steps
      BUNDLE_GEMFILE: ${{ github.workspace }}/gemfiles/${{ matrix.gemfile }}.gemfile
      - uses: actions/checkout@v3
      - uses: ruby/setup-ruby@v1
          ruby-version: '3.0'
          bundler-cache: true # runs 'bundle install' and caches installed gems automatically
      - run: bundle exec rake

See the GitHub Actions documentation for more details about the workflow syntax and the condition and expression syntax.

Supported Version Syntax

  • 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 (2.6.10)
  • 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 reads from the project's .ruby-version file
  • .tool-versions reads from the project's .tool-versions file
  • If the ruby-version input is not specified, .ruby-version is tried first, followed by .tool-versions

Working Directory

The working-directory input can be set to resolve .ruby-version, .tool-versions and Gemfile.lock if they are not at the root of the repository, see action.yml for details.


By default, the default RubyGems version that comes with each Ruby is used. However, users can optionally customize the RubyGems version that they want by setting the rubygems input.

See action.yml for more details about the rubygems input.

If you're running into ArgumentError: wrong number of arguments (given 4, expected 1) errors with a stacktrace including Psych and RubyGems entries, you should be able to fix them by setting rubygems: 3.0.0 or higher.


By default, if there is a Gemfile.lock file (or $BUNDLE_GEMFILE.lock or gems.locked) with a BUNDLED WITH section, that version of Bundler will be installed and used. Otherwise, the latest compatible Bundler version is installed (Bundler 2 on Ruby >= 2.4, Bundler 1 on Ruby < 2.4).

This behavior can be customized, see action.yml for more details about the bundler input.

Caching bundle install automatically

This action provides a way to automatically run bundle install and cache the result:

    - uses: ruby/setup-ruby@v1
        bundler-cache: true

Note that any step doing bundle install (for the root Gemfile) or gem install bundler can be removed with bundler-cache: true.

This caching speeds up installing gems significantly and avoids too many requests to
It needs a Gemfile (or $BUNDLE_GEMFILE or gems.rb) under the working-directory.
If there is a Gemfile.lock (or $BUNDLE_GEMFILE.lock or gems.locked), bundle config --local deployment true is used.

To use a Gemfile which is not at the root or has a different name, set BUNDLE_GEMFILE in the env at the job level as shown in the example.

bundle config

When using bundler-cache: true you might notice there is no good place to run bundle config ... commands. These can be replaced by BUNDLE_* environment variables, which are also faster. They should be set in the env at the job level as shown in the example. To find the correct the environment variable name, see the Bundler docs or look at .bundle/config after running bundle config --local KEY VALUE locally. You might need to "-quote the environment variable name in YAML if it has unusual characters like /.

To perform caching, this action will use bundle config --local path $PWD/vendor/bundle.
Therefore, the Bundler path should not be changed in your workflow for the cache to work (no bundle config path).

How it Works

When there is no lockfile, one is generated with bundle lock, which is the same as bundle install would do first before actually fetching any gem. In other words, it works exactly like bundle install. The hash of the generated lockfile is then used for caching, which is the only correct approach.

Dealing with a corrupted cache

In some rare scenarios (like using gems with C extensions whose functionality depends on libraries found on the system at the time of the gem's build) it may be necessary to ignore contents of the cache and get and build all the gems anew. In order to achieve this, set the cache-version option to any value other than 0 (or change it to a new unique value if you have already used it before.)

    - uses: ruby/setup-ruby@v1
        bundler-cache: true
        cache-version: 1

Caching bundle install manually

It is also possible to cache gems manually, but this is not recommended because it is verbose and very difficult to do correctly. There are many concerns which means using actions/cache is never enough for caching gems (e.g., incomplete cache key, cleaning old gems when restoring from another key, correctly hashing the lockfile if not checked in, OS versions, ABI compatibility for ruby-head, etc). So, please use bundler-cache: true instead and report any issue.


Note that running CI on Windows can be quite challenging if you are not very familiar with Windows. It is recommended to first get your build working on Ubuntu and macOS before trying Windows.

  • Use Bundler 2.2.18+ on Windows (older versions have bugs) by not setting the bundler: input and ensuring there is no BUNDLED WITH 1.x.y in a checked-in Gemfile.lock.
  • The default shell on Windows is not Bash but PowerShell. This can lead issues such as multi-line scripts not working as expected.
  • The PATH contains multiple compiler toolchains. Use where.exe to debug which tool is used.
  • For Ruby ≥ 2.4, MSYS2 is prepended to the Path, similar to what RubyInstaller2 does.
  • For Ruby < 2.4, the DevKit MSYS tools are installed and prepended to the Path.
  • Use JRuby 9.2.20+ on Windows (older versions have bugs).


It is highly recommended to use ruby/setup-ruby@v1 for the version of this action. This will provide the best experience by automatically getting bug fixes, new Ruby versions and new features.

If you instead choose a specific version (v1.2.3) or a commit sha, there will be no automatic bug fixes and it will be your responsibility to update every time the action no longer works. Make sure to always use the latest release before reporting an issue on GitHub.

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

Using self-hosted runners

This action might work with self-hosted runners if the virtual environment is very similar to the ones used by GitHub runners. Notably:

  • Make sure to use the same operating system and version.
  • Set the environment variable ImageOS on the runner to the corresponding value on GitHub-hosted runners (e.g. ubuntu18/macos1015/win19). This is necessary to detect the operating system and version.
  • Make sure to use the same version of libssl.
  • Make sure that the operating system has libyaml-0 and libgmp installed
  • The default tool cache directory (/opt/hostedtoolcache on Linux, /Users/runner/hostedtoolcache on macOS, C:/hostedtoolcache/windows on Windows) must be writable by the runner user. This is necessary since the Ruby builds embed the install path when built and cannot be moved around.
  • /home/runner must be writable by the runner user.

In other cases, please use a system Ruby or install Ruby manually instead.

On a self-hosted runner you need to define the ImageOs as an evironment variable on the host, you can do this in the ~/actions-runner/.env file (See #230).


This action used to be at eregon/use-ruby-action and was moved to the ruby organization. Please update if you are using eregon/use-ruby-action.


The current maintainer of this action is @eregon. Most of the Windows logic is based on work by MSP-Greg. Many thanks to MSP-Greg and Lars Kanis for the help with Ruby Installer.