07-python-cicd.yml

# Demo 7 — CI/CD: Python Application Pipeline
# Full pipeline: lint → test → build artifact → deploy (staging + production)
# Ties together concepts from all previous demos

name: "Demo 7 — Python CI/CD"

on:
  push:
    paths:
      - "demos/demo7/**"
      - ".github/workflows/07-python-cicd.yml"
    branches: [main]
  pull_request:
    paths:
      - "demos/demo7/**"
      - ".github/workflows/07-python-cicd.yml"
  workflow_dispatch:

permissions:
  contents: read

defaults:
  run:
    working-directory: demos/demo7

jobs:
  # ─── Job 1: Lint with Ruff ──────────────────────────────────────
  lint:
    name: "Lint (Ruff)"
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Setup Python
        uses: actions/setup-python@v5
        with:
          python-version: "3.12"

      - name: Cache pip
        uses: actions/cache@v4
        with:
          path: ~/.cache/pip
          key: pip-${{ runner.os }}-lint-${{ hashFiles('demos/demo7/requirements.txt') }}
          restore-keys: pip-${{ runner.os }}-lint-

      - name: Install Ruff
        run: pip install ruff

      - name: Run Ruff linter
        run: |
          echo "::group::🔍 Ruff lint results"
          ruff check . --output-format=text
          echo "::endgroup::"

      - name: Run Ruff formatter check
        run: |
          ruff format --check .

      - name: Lint summary
        if: always()
        run: |
          cat >> "$GITHUB_STEP_SUMMARY" <<'EOF'
          ## 🔍 Lint Results
          - **Tool:** Ruff
          - **Status:** ${{ job.status == 'success' && '✅ Passed' || '❌ Failed' }}
          EOF

  # ─── Job 2: Test with Pytest ────────────────────────────────────
  test:
    name: "Test (Python ${{ matrix.python-version }})"
    runs-on: ubuntu-latest
    strategy:
      matrix:
        python-version: ["3.11", "3.12"]
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Setup Python ${{ matrix.python-version }}
        uses: actions/setup-python@v5
        with:
          python-version: ${{ matrix.python-version }}

      - name: Cache pip
        uses: actions/cache@v4
        with:
          path: ~/.cache/pip
          key: pip-${{ runner.os }}-py${{ matrix.python-version }}-${{ hashFiles('demos/demo7/requirements.txt') }}
          restore-keys: pip-${{ runner.os }}-py${{ matrix.python-version }}-

      - name: Install dependencies
        run: pip install -r requirements.txt

      - name: Run tests
        run: |
          echo "::group::🧪 Pytest output"
          pytest test_app.py -v --tb=short --junitxml=test-results.xml 2>&1 | tee pytest-output.txt
          echo "::endgroup::"

      - name: Test summary
        if: always()
        run: |
          TESTS=$(grep -c "PASSED\|FAILED" pytest-output.txt 2>/dev/null || echo "?")
          PASSED=$(grep -c "PASSED" pytest-output.txt 2>/dev/null || echo "0")
          cat >> "$GITHUB_STEP_SUMMARY" <<EOF
          ## 🧪 Test Results (Python ${{ matrix.python-version }})
          - **Total tests:** ${TESTS}
          - **Passed:** ${PASSED}
          - **Status:** ${{ job.status == 'success' && '✅ All passed' || '❌ Some failed' }}
          EOF

      - name: Upload test results
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: test-results-py${{ matrix.python-version }}
          path: |
            demos/demo7/test-results.xml
            demos/demo7/pytest-output.txt

  # ─── Job 3: Build artifact ─────────────────────────────────────
  build:
    name: "Build"
    runs-on: ubuntu-latest
    needs: [lint, test]
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Setup Python
        uses: actions/setup-python@v5
        with:
          python-version: "3.12"

      - name: Create build artifact
        run: |
          echo "::group::📦 Building application package"
          BUILD_DIR="build"
          mkdir -p "$BUILD_DIR"

          # Copy application code
          cp app.py "$BUILD_DIR/"
          cp requirements.txt "$BUILD_DIR/"

          # Add build metadata
          cat > "$BUILD_DIR/BUILD_INFO.txt" <<EOF
          Build Date:   $(date -u)
          Commit SHA:   ${{ github.sha }}
          Commit Short: ${{ github.sha }}
          Branch:       ${{ github.ref_name }}
          Run ID:       ${{ github.run_id }}
          Run Number:   ${{ github.run_number }}
          Python:       3.12
          EOF

          echo "::endgroup::"
          echo "✅ Build artifact created"

      - name: Upload build artifact
        uses: actions/upload-artifact@v4
        with:
          name: app-build-${{ github.run_number }}
          path: demos/demo7/build/
          retention-days: 5

      - name: Build summary
        run: |
          cat >> "$GITHUB_STEP_SUMMARY" <<EOF
          ## 📦 Build Artifact
          - **Artifact name:** \`app-build-${{ github.run_number }}\`
          - **Commit:** \`${{ github.sha }}\`
          - **Contents:** app.py, requirements.txt, BUILD_INFO.txt
          EOF

  # ─── Job 4: Deploy to Staging ───────────────────────────────────
  deploy-staging:
    name: "Deploy → Staging"
    runs-on: ubuntu-latest
    needs: [build]
    environment: staging
    steps:
      - name: Download build artifact
        uses: actions/download-artifact@v4
        with:
          name: app-build-${{ github.run_number }}
          path: deploy/

      - name: Verify artifact
        run: |
          echo "::group::📋 Artifact contents"
          ls -la deploy/
          cat deploy/BUILD_INFO.txt
          echo "::endgroup::"
        working-directory: .

      - name: Simulate staging deployment
        run: |
          echo "🚀 Deploying to STAGING..."
          echo "   → Extracting artifact"
          echo "   → Installing dependencies"
          echo "   → Starting application"
          sleep 2
          echo "   → Running smoke test"
          python deploy/app.py
          echo ""
          echo "✅ Staging deployment complete!"
        working-directory: .

      - name: Staging summary
        run: |
          cat >> "$GITHUB_STEP_SUMMARY" <<EOF
          ## 🚀 Staging Deployment
          - **Environment:** staging
          - **Artifact:** \`app-build-${{ github.run_number }}\`
          - **Status:** ✅ Deployed and smoke-tested
          EOF
        working-directory: .

  # ─── Job 5: Deploy to Production (with approval gate) ──────────
  deploy-production:
    name: "Deploy → Production"
    runs-on: ubuntu-latest
    needs: [deploy-staging]
    environment: production
    steps:
      - name: Download build artifact
        uses: actions/download-artifact@v4
        with:
          name: app-build-${{ github.run_number }}
          path: deploy/

      - name: Simulate production deployment
        run: |
          echo "🚀 Deploying to PRODUCTION..."
          echo "   → Same artifact that passed staging"
          cat deploy/BUILD_INFO.txt
          sleep 2
          echo ""
          echo "   → Running smoke test"
          python deploy/app.py
          echo ""
          echo "✅ Production deployment complete!"
        working-directory: .

      - name: Production summary
        run: |
          cat >> "$GITHUB_STEP_SUMMARY" <<EOF
          ## 🚀 Production Deployment
          - **Environment:** production
          - **Artifact:** \`app-build-${{ github.run_number }}\`
          - **Status:** ✅ Deployed
          - **Same artifact as staging:** Yes — build once, deploy many
          EOF
        working-directory: .