update_build_environment.yml

name: Rebuild and publish new ubcdsci/py-intro-to-ds image on DockerHub
on:
  pull_request:
    types: [opened, synchronize]
    branches:
      - 'main'

jobs:
  rebuild-docker:
    name: Rebuild docker image
    runs-on: ubuntu-latest
    permissions:
      contents: write
    steps:
    - name: Checkout PR branch
      uses: actions/checkout@v3
      with:
        fetch-depth: '0'
        ref: ${{ github.head_ref }}
    - name: Check if Dockerfile needs to be rebuilt
      id: check-stale
      run: |
        echo "Checking if Dockerfile was modified since last commit on this PR"
        echo "GitHub PR action type: ${{ github.event.action }}"
        if [ "${{ github.event.action }}" == "opened" ]; then
            echo "GitHub base ref: ${{ github.event.pull_request.base.sha }}"
            echo "GitHub head ref: ${{ github.event.pull_request.head.sha }}"
            BEFORE=${{ github.event.pull_request.base.sha }}
            AFTER=${{ github.event.pull_request.head.sha }}
        else
            echo "GitHub event before: ${{ github.event.before }}"
            echo "GitHub event after: ${{ github.event.after }}"
            BEFORE=${{ github.event.before }}
            AFTER=${{ github.event.after }}
        fi
        if git diff --quiet $BEFORE $AFTER Dockerfile; then
            echo "PR synchronized, but Dockerfile was not edited. Not rebuilding the image."
            echo "stale_dockerfile=false" >> "$GITHUB_OUTPUT"
        else
            echo "PR synchronized, and Dockerfile was edited, so rebuilding the image."
            echo "stale_dockerfile=true" >> "$GITHUB_OUTPUT"
        fi
    - name: Rebuild and publish image
      if: ${{ steps.check-stale.outputs.stale_dockerfile == 'true' }}
      id: rebuild
      uses: elgohr/Publish-Docker-Github-Action@v5
      with:
        name: ubcdsci/py-intro-to-ds
        username: ${{ secrets.DOCKER_USERNAME }}
        password: ${{ secrets.DOCKER_PASSWORD }}
        dockerfile: Dockerfile
        snapshot: true
    - name: Update build_html.sh script
      if: ${{ steps.check-stale.outputs.stale_dockerfile == 'true' }}
      run: |
        git config --local user.email "action@github.com"
        git config --local user.name "GitHub Action"
        git pull origin ${{ github.head_ref }}
        sed 's/ubcdsci\/py-intro-to-ds:[[:alnum:]]\+/ubcdsci\/py-intro-to-ds:${{ steps.rebuild.outputs.snapshot-tag }}/g' build_html.sh > build_html.tmp && mv build_html.tmp build_html.sh
        chmod u+x build_html.sh
        git add build_html.sh
        git commit -m "update build_html.sh script with new docker image"
    - name: Update build_pdf.sh script
      if: ${{ steps.check-stale.outputs.stale_dockerfile == 'true' }}
      run: |
        git config --local user.email "action@github.com"
        git config --local user.name "GitHub Action"
        git pull origin ${{ github.head_ref }}
        sed 's/ubcdsci\/py-intro-to-ds:[[:alnum:]]\+/ubcdsci\/py-intro-to-ds:${{ steps.rebuild.outputs.snapshot-tag }}/g' build_pdf.sh > build_pdf.tmp && mv build_pdf.tmp build_pdf.sh
        chmod u+x build_pdf.sh
        git add build_pdf.sh
        git commit -m "update build_pdf.sh script with new docker image"
    - name: Push changes to build scripts
      if: ${{ steps.check-stale.outputs.stale_dockerfile == 'true' }}
      uses: ad-m/github-push-action@master
      with:
        github_token: ${{ secrets.GITHUB_TOKEN }}
        branch: ${{ github.head_ref }}