docker-build.yml

---
#
# https://docs.docker.com/build/ci/github-actions/
# https://github.com/docker/build-push-action
# https://docs.github.com/en/actions/creating-actions/creating-a-docker-container-action
#
name: Docker Build Workflow
on:  # yamllint disable-line rule:truthy
  schedule:
    #         ┌───────────── minute (0 - 59)
    #         │ ┌───────────── hour (0 - 23)
    #         │ │ ┌───────────── day of the month (1 - 31)
    #         │ │ │ ┌───────────── month (1 - 12 or JAN-DEC)
    #         │ │ │ │ ┌───────────── day of the week (0 - 6 or SUN-SAT)
    #         │ │ │ │ │
    #         │ │ │ │ │
    #         │ │ │ │ │
    #         * * * * *
    - cron: '15 8 1 * *'
  workflow_dispatch:
  pull_request:

env:
  IMAGE_NAME: ci-generic-debian

defaults:
  run:
    shell: bash

jobs:
  stage1:
    name: Change Check
    runs-on: 'ubuntu-latest'
    outputs:
      docs_changed: ${{ steps.check_file_changed.outputs.docs_changed }}
      matrix_exercise: ${{ steps.check_file_changed.outputs.matrix_exercise }}
    env:
      re_change: '^(Dockerfile.*|.github/docker/.*|.github/workflows/docker-build.yml)$'
    steps:
      - name: Check GitHub Vars
        id: github-vars
        run: set | grep -e ^CI -e ^GITHUB_ -e ^RUNNER_
      - name: Checkout Repo
        id: checkout-repo
        uses: actions/checkout@v3
        with:
          fetch-depth: 0
          ref: ${{ github.ref }}
          submodules: recursive
      - name: Get Change List
        id: check_file_changed
        run: |-
          {
            printf "Workflow: %s\n\n" "${GITHUB_WORKFLOW}"
            printf "Runner: name[%s] arch[%s]\n" "${RUNNER_NAME}" "${RUNNER_ARCH}"
            printf "Repo: %s\n" "${GITHUB_REPOSITORY}"
            printf "User: %s\n" "${GITHUB_TRIGGERING_ACTOR}"
            printf "\n"
          } | tee -a "${GITHUB_STEP_SUMMARY}"

          # Diff HEAD with the previous commit then output to stdout.
          declare -a GIT_DIFF
          mapfile -t GIT_DIFF < <(git diff --name-only HEAD^ HEAD | tee /tmp/changed_files.txt)
          {
            printf "=== Which files changed? ===\n"
            printf "\n"
            printf "\`\`\`text\n"
            printf "%s\n" "${GIT_DIFF[@]}"
            printf "\`\`\`\n"
            printf "\n"
          } | tee -a "${GITHUB_STEP_SUMMARY}"

          # Get changed exercise list.
          if [[ ${GITHUB_EVENT_NAME} != pull_request ]]; then
            printf "Manual run, pretending we have a diff.\n"
            HAS_DIFF=true
          fi
          printf "\n"

          # Check if the files are present in the changed file list (added, modified, deleted) then output to stdout.
          HAS_DIFF="${HAS_DIFF:-false}"
          printf "=== Which Docker files changed? ===\n"
          if printf "%s\n" "${GIT_DIFF[@]}" | grep -E "${{ env.re_change }}"; then
            HAS_DIFF=true
          fi
          printf "\n"

          # Did Docker files change?
          {
            printf "=== Did Docker files change? ===\n"
            printf "Changes Detected: %s\n" "${HAS_DIFF}"
            printf "\n"
            printf "\`\`\`text\n"
            printf "%s\n" "${GIT_DIFF[@]}" | grep -E "${{ env.re_change }}" || true
            printf "\`\`\`\n"
            printf "\n"
          } | tee -a "${GITHUB_STEP_SUMMARY}"

          # Set the output named "docs_changed"
          printf "%s=%s\n" "docs_changed" "${HAS_DIFF}" >> "${GITHUB_OUTPUT}"
  stage2:
    name: Docker Build
    strategy:
      matrix:
        os: ["ubuntu-latest"]
    runs-on: "${{ matrix.os }}"
    needs: [stage1]
    if: needs.stage1.outputs.docs_changed == 'True'
    outputs:
      tag_date: ${{ steps.setup_image_info.outputs.tag_date }}
    steps:
      - name: Setup Env [${{ matrix.os }}]
        id: setup_image_info
        run: |-
          tag_date="$(date +%Y%m%d)"
          printf "%s=%s\n" "tag_date" "${tag_date}" >> "${GITHUB_OUTPUT}"
      - name: Docker Build Checkout [${{ matrix.os }}]
        uses: actions/checkout@v3
      - name: Login to Docker Hub [${{ matrix.os }}]
        uses: docker/login-action@v2
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}
      - name: Set up Docker Buildx [${{ matrix.os }}]
        uses: docker/setup-buildx-action@v2
      - name: Build and push [${{ matrix.os }}]
        uses: docker/build-push-action@v4
        with:
          context: .
          file: ./Dockerfile
          push: true
          tags: ${{ secrets.DOCKERHUB_USERNAME }}/${{ env.IMAGE_NAME }}:latest,${{ secrets.DOCKERHUB_USERNAME }}/${{ env.IMAGE_NAME }}:${{ steps.setup_image_info.outputs.tag_date }}
  stage3:
    name: Docker Test
    env:
      ORG: ${{ secrets.DOCKERHUB_USERNAME }}
      IMAGE_NAME: ci-generic-debian
    strategy:
      matrix:
        os:
          - vpayno/ci-generic-debian:latest
          - vpayno/ci-generic-debian:${{ needs.stage2.outputs.tag_date }}
    runs-on: ubuntu-latest
    container: ${{ matrix.os }}
    needs: [stage2]
    steps:
      - name: Test New Container [${{ matrix.os }}]
        run: |-
          printf "%s\n" "Hello World!"
      - name: Docker Build Summary [${{ matrix.os }}]
        run: |-
          ORG_IMAGE="${{ secrets.DOCKERHUB_USERNAME }}/${{ env.IMAGE_NAME }}"
          TOKEN="$(curl "https://auth.docker.io/token?service=registry.docker.io&scope=repository:${ORG_IMAGE}:pull" | jq -r .access_token)"
          {
            printf "Docker Hub Image Info\n"
            curl -sS --header "Authorization: Bearer ${TOKEN}" "https://index.docker.io/v2/${ORG_IMAGE}/tags/list" | jq .
          } | tee -a "${GITHUB_STEP_SUMMARY}"