A GitHub action to install and setup a Linux distribution for the Windows Subsystem for Linux (WSL).

Beginning with windows-2019 virtual environment for GitHub actions, WSLv1 is enabled. However, there is no Linux distribution installed by default and there is also no easy shell for run steps that executes commands within a WSL distribution.

This action provides an easy way to install Linux distributions for WSL, update those to the latest packages and install additional packages in them. It also provides a comfortable shell for run steps that uses the default WSL distribution and distribution-specific shells if you set up multiple distributions.

WSLv2 is not explicitly supported, because as of this writing neither the Windows version running on GitHub hosted runners supports WSLv2, nor is Hyper-V enabled which is also necessary to enable WSLv2. If you use a self-hosted runner on a Windows OS that is new enough with enabled Hyper-V and default WSL version set to 2, this action will probably run just fine, but this setup is untested and not explicitly supported. If you want to provide a self-hosted runner with a sufficient setup for this action to use or need changes for supporting WSLv2 I will happily accept this. With a proper test environment (self-hosted runner) that will stay available, I would also add proper official support where you can select the WSL version in your workflow files.

Thanks to the provided typings, it is possible to use this action in a type-safe way using https://github.com/typesafegithub/github-workflows-kt which allows writing workflow files using a type-safe Kotlin DSL.

• Usage
  • Action
  • Shell
  • Default Shell
  • Inputs
    • distribution
    • use-cache
    • wsl-conf
    • set-as-default
    • update
    • additional-packages
    • wsl-shell-user
    • wsl-shell-command
  • Outputs
    • wsl-shell-wrapper-path
    • wsl-shell-distribution-wrapper-path
• Version Numbers
• License

To use this action with all inputs set to their default value, just use its name.

Example:

- uses: Vampire/setup-wsl@v3

This will first check whether the distribution is installed already. If not, it will be installed and also configured as default WSL distribution. Independently of whether the distribution was installed already, the wsl-shell wrapper for the default WSL distribution and the one for the distribution this action is running for are rewritten to disk for later usage in run steps.

This action can be configured via inputs to configure the distribution as default even if it is not going to be installed or not to configure the distribution as default even if it is going to be installed by this action. Furthermore, inputs can be used to make this action update the installed distribution to the latest available packages after installation, to install additional packages, and to use a different command for the wsl-shell wrapper.

By default the generated wsl-shell wrapper is called wsl-bash (and wsl-bash_<distribution id>) and ultimately calls the command bash --noprofile --norc -euo pipefail '/the/generated/run_script'. If you want a different shell being used or different options being used, you can configure the shell command using the wsl-shell-command input. The name of the wrapper script is derived from the first word in the wsl-shell-command input, so if you configure ash -eu as command, the script is named wsl-ash (and wsl-ash_<distribution id>). Differently named wsl-shell wrappers from former action executions are not deleted.

The wsl-shell wrappers by default execute the run-step scripts as the default user of the distribution which usually will be the user root. If you want a different user being used by default, you can configure the user using the wsl-shell-user input for the wsl-shell wrapper scripts created or updated by the current action invocation. Additionally, the generated wsl-shell wrappers optionally accept as first two parameters -u and a user that should be used for this invocation.

The wsl-shell wrapper without distribution id suffix always uses the default WSL distribution at the time it is actually invoked. If you want to target a specific distribution, either make sure it is the default, for example using this action, or use the distribution specific wsl-shell wrapper that always uses the according WSL distribution it is created for.

Examples:

- shell: wsl-bash {0}
  run: id

- shell: wsl-bash_Ubuntu-20.04 {0}
  run: |
      npm ci
      npm run build
      npm run package

- shell: wsl-bash -u root {0}
  run: id

If you want to use the wsl-shell wrapper for all run steps (unless a shell is specified explicitly for it), GitHub Actions also lets you configure the default shell for the whole workflow or for a specific job, by using the defaults key on the respective level.

Example:

defaults:
    run:
        shell: wsl-bash {0}

steps:
    - uses: Vampire/setup-wsl@v3

    - run: |
          npm ci
          npm run build
          npm run package

The WSL distribution to install, update, or configure.

If the distribution is not yet installed, it will be installed first. After successful installation the distribution is also configured as default WSL distribution if not disabled using the set-as-default input.

If the distribution is already installed, the default WSL distribution is not changed, except if enabled using the set-as-default input.

The first installed WSL distribution is automatically the default one, independently of the set-as-default input.

Either way, the wsl-shell wrapper scripts are created or overwritten according to the current action configuration.

Ubuntu-22.04 and Ubuntu-20.04 can not be used together at the same time. They use the same WSL distribution ID, so the second that is used will not be installed as the first one will be found as already installed by WSL distribution ID.

The values currently supported by this action are:

• Debian (default)
• Alpine
• kali-linux
• openSUSE-Leap-15.2
• Ubuntu-24.04
• Ubuntu-22.04
• Ubuntu-20.04
• Ubuntu-18.04
• Ubuntu-16.04

Example:

- uses: Vampire/setup-wsl@v3
  with:
      distribution: Ubuntu-18.04

Whether to use the cache for the downloaded distribution installer. This saves time in subsequent runs, jobs, or workflows but consumes space from the available cache space of the repository. Refer to actions/cache documentation for current usage limits.

Default value:

• 'true' if the cache feature is available
• 'false' if the cache feature is not available, for example because it was disabled on a GitHub Enterprise instance

Example:

- uses: Vampire/setup-wsl@v3
  with:
      use-cache: 'false'

The content that will be written to /etc/wsl.conf of the installed distribution. This can be used to adjust various settings as documented at https://docs.microsoft.com/en-us/windows/wsl/wsl-config#configuration-settings-for-wslconf. This can also be used if the distribution is installed already.

WARNING: Setting this option will overwrite any existing content of the file. Some distributions like Ubuntu-24.04 might already ship with a wsl.conf file. Make sure to check whether a file exists by default and whether you want to included its contents in your configured value.

Default value: none

Example:

- uses: Vampire/setup-wsl@v3
  with:
      wsl-conf: |
          [automount]
          root = /

Whether to set the distribution as default WSL distribution. This can also be used if the distribution is installed already.

Default value:

• 'true' if the distribution is going to be installed
• 'false' if the distribution is only getting configured, updated, or additional packages installed
• the first installed WSL distribution is automatically the default one, independently of this input

Example:

- uses: Vampire/setup-wsl@v3
  with:
      set-as-default: 'false'

Whether to update the distribution after installation. This can also be used if the distribution is installed already.

Default value: 'false'

Example:

- uses: Vampire/setup-wsl@v3
  with:
      update: 'true'

Space separated list of additional packages to install after distribution installation. This can also be used if the distribution is installed already.

Default value: none

Example:

- uses: Vampire/setup-wsl@v3
  with:
      additional-packages:
          dos2unix
          ash

The distribution user that should be used to execute run-step scripts with wsl-shell wrapper scripts that are created or updated by the current action invocation. If no value is given, the default user of the distribution at script execution time is used. If the user does not yet exists in the distribution, it is automatically added.

Default value: none

Example:

- uses: Vampire/setup-wsl@v3
  with:
      wsl-shell-user: test

The command that is used in the wsl-shell wrapper scripts to execute the run-step script file. The name of the wrapper scripts will be derived from the first word in this input prefixed with wsl-. This means that for the default value, the wrapper scripts will start with wsl-bash.

The run-step script file will be given as additional parameter in single quotes after the given string, separated with one space character. The latter point is important, if you need to escape this space character as shown in the examples.

If the given string contains at least once the sequence {0}, all occurrences of it will be replaced by the run-step script file without any quotes or anything and it will not be given as additional parameter. This can be used if the script file is needed within the shell command opposed to as additional parameter.

This input can also be used if the distribution is installed already to change the wrapper scripts or generate additional ones for other shells. Already existing wsl-shell wrapper scripts are only overwritten, if this input is set to a value explicitly. Non-existing wrapper scripts are always generated. So if you want to change the default user using the wsl-shell-user input, you either have to first delete the wrapper script or scripts that should be regenerated or specify a value for this input explicitly. To delete the wsl-shell wrapper scripts, the wsl-shell-wrapper-path output and wsl-shell-distribution-wrapper-path output can be used.

Default value: bash --noprofile --norc -euo pipefail

Examples:

- uses: Vampire/setup-wsl@v3
  with:
      wsl-shell-command: ash -eu

- shell: wsl-ash {0}
  run: id

- shell: wsl-bash {0}
  run: |
      useradd -m -p 4qBD5NWD3IkbU test

- uses: Vampire/setup-wsl@v3
  with:
      wsl-shell-command: bash -c "sudo -u test bash --noprofile --norc -euo pipefail "\

- shell: wsl-bash {0}
  run: id

- uses: Vampire/setup-wsl@v3
  with:
      wsl-shell-command: bash -c "sudo -u test bash --noprofile --norc -euo pipefail '{0}'"

- shell: wsl-bash {0}
  run: id

- uses: Vampire/setup-wsl@v3
  with:
    wsl-shell-command: bash -c "cd && bash --noprofile --norc -euo pipefail '{0}'"

- shell: wsl-bash {0}
  run: pwd

- shell: cmd
  run: DEL /F "${{ steps.execute_action.outputs.wsl-shell-wrapper-path }}"

The path to the wsl-shell wrapper that is generated by the current action invocation. Even if the current action invocation does not actually generate the script, because wsl-shell-command is not set explicitly and the script already exists, this output will be set.

The path to the distribution-specific wsl-shell wrapper that is generated by the current action invocation. Even if the current action invocation does not actually generate the script, because wsl-shell-command is not set explicitly and the script already exists, this output will be set.

Versioning of this GitHub action follows the Semantic Versioning specification.

Releases are tagged following the pattern vX.Y.Z. For GitHub actions it is common to also have a rolling tag for the major version that always points at the latest release within the major version. But as the author personally greatly dislikes rolling tags which are totally against the concept of a tag, instead a vX branch is provided that will always point to the latest release within the major version. As actions can refer tags and branches exactly the same, this will not make any difference for using the action, but it is in the authors opinion cleaner.

Copyright 2020-2023 Björn Kautler

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.