action.yaml

name: GitHub App Authentication

author: liblaf

description: This action authenticates with a GitHub App to generate an installation access token for specified repositories.

inputs:
  app-id:
    description: GitHub App ID
    required: true
  private-key:
    description: GitHub App private key
    required: true
  owner:
    description: The owner of the GitHub App installation (defaults to current repository owner)
    required: false
    default: ${{ github.repository_owner }}
  repositories:
    description: Comma or newline-separated list of repositories to install the GitHub App on (defaults to current repository if owner is unset)
    required: false

outputs:
  token:
    description: GitHub installation access token
    value: ${{ steps.app-token.outputs.token }}
  installation-id:
    description: GitHub App installation ID
    value: ${{ steps.app-token.outputs.installation-id }}
  app-slug:
    description: GitHub App slug
    value: ${{ steps.app-token.outputs.app-slug }}
  commit-user-name:
    description: Name used for the commit user
    value: ${{ steps.app-token.outputs.app-slug }}[bot]
  commit-user-email:
    description: Email address used for the commit user
    value: ${{ steps.get-user-id.outputs.user-id }}+${{ steps.app-token.outputs.app-slug }}[bot]@users.noreply.github.com
  commit-author:
    description: Value used for the commit author. Defaults to the username of whoever triggered this workflow run.
    value: ${{ steps.committer.outputs.string }}

runs:
  using: composite
  steps:
    - name: Create GitHub App Token
      id: app-token
      uses: actions/create-github-app-token@v1
      with:
        app-id: ${{ inputs.app-id }}
        private-key: ${{ inputs.private-key }}
        owner: ${{ inputs.owner }}
        repositories: ${{ inputs.repositories }}
    # ref: <https://github.com/actions/create-github-app-token/blob/main/README.md#create-a-git-committer-string-for-an-app-installation>
    - run: echo "user-id=$(gh api "/users/${{ steps.app-token.outputs.app-slug }}[bot]" --jq .id)" >> "$GITHUB_OUTPUT"
      shell: bash
      name: Get GitHub App User ID
      id: get-user-id
      env:
        GH_TOKEN: ${{ steps.app-token.outputs.token }}
    - run: echo "string=${{ steps.app-token.outputs.app-slug }}[bot] <${{ steps.get-user-id.outputs.user-id }}+${{ steps.app-token.outputs.app-slug }}[bot]@users.noreply.github.com>" >> "$GITHUB_OUTPUT"
      shell: bash
      name: Create a git committer string for an app installation
      id: committer
    - run: |-
        git config --global user.name '${{ steps.app-token.outputs.app-slug }}[bot]'
        git config --global user.email '${{ steps.get-user-id.outputs.user-id }}+${{ steps.app-token.outputs.app-slug }}[bot]@users.noreply.github.com>'
      shell: bash
      name: Configure git CLI for an app's bot user