template_changes.yml

---
# Report template changes by posting them as a comment to a commit
name: Report template changes
# yamllint disable rule:truthy
on:
  push:
    branches:
      - main
# yamllint enable

jobs:
  pre_job:
    runs-on: ubuntu-latest
    outputs:
      should_skip: ${{ steps.skip_check.outputs.skip }}
      fetch_depth: ${{ steps.fetch_depth.outputs.fetch_depth }}
    steps:
      - name: Set up Python
        uses: actions/setup-python@v2
        with:
          python-version: '3.9'
      - name: Skip if this is the first commit in this branch
        # yamllint disable rule:line-length
        run: |
          if [ "${{ github.event.before }}" = "0000000000000000000000000000000000000000" ]; then
            echo "::set-output name=skip::true"
          else
            echo "::set-output name=skip::false"
          fi
        # yamllint enable
        id: skip_check
      - name: Determine fetch depth
        run: |
          import json
          import os
          github_context: dict = json.loads(os.getenv("GITHUB_CONTEXT", "{}"))
          commits: list = github_context.get("event", {}).get("commits", [])
          fetch_depth: int = len(commits) + 1
          print(f"::set-output name=fetch_depth::{fetch_depth}")
        shell: python
        env:
          GITHUB_CONTEXT: ${{ toJson(github) }}
        id: fetch_depth

  template_changes:
    needs: pre_job
    if: ${{ needs.pre_job.outputs.should_skip != 'true' }}
    runs-on: ubuntu-latest
    defaults:
      run:
        working-directory: ./cdk
    steps:
      - uses: actions/checkout@v2
        with:
          fetch-depth: ${{ needs.pre_job.outputs.fetch_depth }}
      - name: Set up Python
        uses: actions/setup-python@v2
        with:
          python-version: '3.9'
      - name: Set up Node.js
        uses: actions/setup-node@v2
        with:
          node-version: '14'
      - name: Install AWS CDK Toolkit
        run: |
          npm install -g aws-cdk@"==2.21.1"
      - name: Install requirements
        run: |
          python -m pip install --upgrade pip setuptools wheel
          python -m pip install --no-deps \
              -r ./requirements/base.txt \
              -r ./requirements/dev.txt
          mkdir templates
      - name: Generate previous push's templates
        run: |
          echo "::group::previous push"
          git checkout ${PREV_SHA} || git checkout "${CURRENT_SHA}~$((${FETCH_DEPTH}-1))"
          python -m venv ../.venv-old
          . ../.venv-old/bin/activate
          python -m pip install --upgrade pip setuptools wheel
          python -m pip install --no-deps \
              -r ./requirements/base.txt \
              -r ./requirements/dev.txt
          cdk synth playground > templates/playground.old.yaml
          cdk synth fargate > templates/fargate.old.yaml
          deactivate
          echo "::endgroup::"
          echo "::group::Switch back to HEAD"
          git checkout ${CURRENT_SHA}
          echo "::endgroup::"
        env:
          PREV_SHA: ${{ github.event.before }}
          CURRENT_SHA: ${{ github.sha }}
          FETCH_DEPTH: ${{ needs.pre_job.outputs.fetch_depth }}
      - name: Generate CDK diff
        run: |
          cdk --no-color diff \
              --template ./templates/playground.old.yaml \
              playground 2>&1 | tee ./templates/playground.diff
          cdk --no-color diff \
              --template ./templates/fargate.old.yaml \
              fargate 2>&1 | tee ./templates/fargate.diff
      - name: Generate templates
        run: |
          cdk synth playground > ./templates/playground.yaml
          cdk synth fargate > ./templates/fargate.yaml
      - name: Report template changes
        run: |
          ls -l ./templates/
          python ../.github/workflow_utils/pretty_diff.py
        env:
          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"