.github/workflows/deploy-site.yml

# Builds and deploys the site if the build was successful
name: Build & Deploy Site

# Conditions necessary to trigger a build
on:
  push:
    # Ignore pushes on all branches by default
    # branches that should trigger a build must be explicitly excluded from the ignore using '!BRANCH_NAME'
    branches-ignore:
      - '**'
      - '!master'

    # Only build if a file in one of these paths has been changed
    #
    # This list must not contains directories which are modified and commited as part of this action
    # Such a setup would lead to an infinite loop where the push as part of the action triggers a new run of the action
    paths:
      - 'src/main/asciidoc/**'
      - 'src/main/template/**'

jobs:
  build:
    name: Build & Deploy Site
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v2
        with:
          fetch-depth: 1

      - name: Build Site
        run: mvn clean install

      # Determines the short sha of the commit that triggered the build
      - name: Determine Short SHA
        if: success()
        id: short-sha
        run: |
          short_sha=$(git rev-parse --short=10 $GITHUB_SHA)
          echo "::set-output name=short_sha::$short_sha"
        shell: 'bash'

      # Determine the author data of the HEAD commit which will be used for the deploy commit
      - name: Determine HEAD Author Data
        if: success()
        id: author-data
        run: |
          author_name=$(git log -1 --format='%aN' HEAD)
          echo "::set-output name=author_name::$author_name"
          author_email=$(git log -1 --format='%aE' HEAD)
          echo "::set-output name=author_email::$author_email"
        shell: 'bash'

      # Commits any changes to the 'docs/' directory using the credentials of the current HEAD commit; does nothing if there is nothing to commit
      - name: Commit Result
        if: success()
        run: |
          echo "Adding changes"
          git add 'docs/'
          if $(git diff -s --cached --exit-code)
            then
              # nothing staged
              echo "Nothing to commit"
              exit 0
          fi
          echo "Setting up author data"
          git config user.name "${{ steps.author-data.outputs.author_name }}"
          git config user.email "${{ steps.author-data.outputs.author_email }}"
          echo "Commiting changes"
          git commit -m "Auto-deploy site for commit ${{ steps.short-sha.outputs.short_sha }}"
          echo "Pushing changes"
          git push
        shell: 'bash'