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Desafio 19: Fundamentos do GitHub Actions

Plataforma: GitHub-first

Este desafio foca em GitHub Actions. Equivalentes no Azure DevOps são mencionados quando relevante.

Habilidades do exame​

  • Selecionar uma solução de automação de deploy, incluindo GitHub Actions
  • Desenvolver pipelines usando YAML

Cenário​

A Contoso Ltd está migrando seus pipelines de CI/CD do Jenkins para o GitHub Actions. A aplicação principal é uma API REST em Node.js (Express.js) que é containerizada e implantada no Azure App Service. A equipe precisa de um workflow completo que lide com build, testes, criação de imagem de contêiner e deploys em estágios.

A estrutura do repositório:

contoso-api/
  src/
    index.js
    routes/
    middleware/
  tests/
    unit/
    integration/
  Dockerfile
  package.json
  .github/
    workflows/
    actions/

Tarefa 1: Criar o workflow de CI com estágios de build e teste​

Crie .github/workflows/ci-cd.yml com triggers para push na main e pull requests:

name: Contoso API CI/CD

on:
  push:
    branches: [main]
  pull_request:
    branches: [main]
  workflow_dispatch:
    inputs:
      environment:
        description: "Target environment"
        required: true
        default: "staging"
        type: choice
        options:
          - staging
          - production
      skip_tests:
        description: "Skip test execution"
        required: false
        type: boolean
        default: false

env:
  NODE_VERSION: "20.x"
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}

jobs:
  build:
    name: Build and lint
    runs-on: ubuntu-latest
    outputs:
      version: ${{ steps.version.outputs.version }}
      sha_short: ${{ steps.version.outputs.sha_short }}
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Set up Node.js
        uses: actions/setup-node@v4
        with:
          node-version: ${{ env.NODE_VERSION }}
          cache: "npm"

      - name: Install dependencies
        run: npm ci

      - name: Run linter
        run: npm run lint

      - name: Generate version info
        id: version
        run: |
          VERSION=$(node -p "require('./package.json').version")
          SHA_SHORT=$(git rev-parse --short HEAD)
          echo "version=${VERSION}" >> $GITHUB_OUTPUT
          echo "sha_short=${SHA_SHORT}" >> $GITHUB_OUTPUT

      - name: Build application
        run: npm run build

      - name: Upload build artifact
        uses: actions/upload-artifact@v4
        with:
          name: build-output
          path: dist/
          retention-days: 5

  test:
    name: Run tests
    needs: build
    runs-on: ubuntu-latest
    if: ${{ !inputs.skip_tests }}
    strategy:
      matrix:
        test-type: [unit, integration]
    services:
      redis:
        image: redis:7-alpine
        ports:
          - 6379:6379
        options: >-
          --health-cmd "redis-cli ping"
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Set up Node.js
        uses: actions/setup-node@v4
        with:
          node-version: ${{ env.NODE_VERSION }}
          cache: "npm"

      - name: Install dependencies
        run: npm ci

      - name: Run ${{ matrix.test-type }} tests
        run: npm run test:${{ matrix.test-type }}
        env:
          REDIS_URL: redis://localhost:6379
          CI: true

      - name: Upload test results
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: test-results-${{ matrix.test-type }}
          path: coverage/

Tarefa 2: Adicionar build Docker e push para o GitHub Container Registry​

Adicione um job que faz build e push da imagem de contêiner:

  docker:
    name: Build and push container image
    needs: [build, test]
    runs-on: ubuntu-latest
    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
    permissions:
      contents: read
      packages: write
    outputs:
      image_tag: ${{ steps.meta.outputs.tags }}
      image_digest: ${{ steps.push.outputs.digest }}
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Log in to GitHub Container Registry
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata for Docker
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            type=sha,prefix=
            type=semver,pattern={{version}},value=${{ needs.build.outputs.version }}
            type=raw,value=latest,enable={{is_default_branch}}

      - name: Build and push image
        id: push
        uses: docker/build-push-action@v5
        with:
          context: .
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max
          build-args: |
            NODE_VERSION=${{ env.NODE_VERSION }}
            BUILD_SHA=${{ needs.build.outputs.sha_short }}

Tarefa 3: Deploy para o Azure App Service com staging e produção​

Adicione jobs de deploy usando environments:

  deploy-staging:
    name: Deploy to staging
    needs: docker
    runs-on: ubuntu-latest
    environment:
      name: staging
      url: https://contoso-api-staging.azurewebsites.net
    steps:
      - name: Log in to Azure
        uses: azure/login@v2
        with:
          creds: ${{ secrets.AZURE_CREDENTIALS }}

      - name: Deploy to Azure App Service (staging slot)
        uses: azure/webapps-deploy@v3
        with:
          app-name: contoso-api
          slot-name: staging
          images: ${{ needs.docker.outputs.image_tag }}

      - name: Run smoke tests against staging
        run: |
          for i in {1..10}; do
            STATUS=$(curl -s -o /dev/null -w "%{http_code}" https://contoso-api-staging.azurewebsites.net/health)
            if [ "$STATUS" = "200" ]; then
              echo "Staging is healthy"
              exit 0
            fi
            echo "Attempt $i: Status $STATUS, retrying..."
            sleep 10
          done
          echo "Staging health check failed"
          exit 1

  deploy-production:
    name: Deploy to production
    needs: deploy-staging
    runs-on: ubuntu-latest
    environment:
      name: production
      url: https://contoso-api.azurewebsites.net
    steps:
      - name: Log in to Azure
        uses: azure/login@v2
        with:
          creds: ${{ secrets.AZURE_CREDENTIALS }}

      - name: Swap staging slot to production
        run: |
          az webapp deployment slot swap \
            --resource-group contoso-rg \
            --name contoso-api \
            --slot staging \
            --target-slot production

Tarefa 4: Criar uma composite action para etapas reutilizáveis​

Crie .github/actions/setup-node-project/action.yml:

name: "Setup Node.js project"
description: "Installs Node.js, caches dependencies, and runs npm ci"

inputs:
  node-version:
    description: "Node.js version to use"
    required: false
    default: "20.x"
  working-directory:
    description: "Working directory for npm commands"
    required: false
    default: "."

outputs:
  cache-hit:
    description: "Whether npm cache was hit"
    value: ${{ steps.cache.outputs.cache-hit }}

runs:
  using: "composite"
  steps:
    - name: Set up Node.js ${{ inputs.node-version }}
      uses: actions/setup-node@v4
      with:
        node-version: ${{ inputs.node-version }}

    - name: Get npm cache directory
      id: npm-cache-dir
      shell: bash
      run: echo "dir=$(npm config get cache)" >> $GITHUB_OUTPUT

    - name: Cache npm dependencies
      id: cache
      uses: actions/cache@v4
      with:
        path: ${{ steps.npm-cache-dir.outputs.dir }}
        key: ${{ runner.os }}-node-${{ inputs.node-version }}-${{ hashFiles('**/package-lock.json') }}
        restore-keys: |
          ${{ runner.os }}-node-${{ inputs.node-version }}-

    - name: Install dependencies
      shell: bash
      working-directory: ${{ inputs.working-directory }}
      run: npm ci

Use a composite action no workflow:

      - name: Setup project
        uses: ./.github/actions/setup-node-project
        with:
          node-version: ${{ env.NODE_VERSION }}

Tarefa 5: Configurar secrets e variáveis de ambiente​

Configure os seguintes secrets e variáveis nos níveis de repositório e environment:

# Repository secrets (available to all workflows)
gh secret set AZURE_CREDENTIALS --body '{"clientId":"...","clientSecret":"...","subscriptionId":"...","tenantId":"..."}'

# Environment-specific secrets
gh secret set DB_CONNECTION_STRING --env staging --body "Server=staging-db.database.windows.net;..."
gh secret set DB_CONNECTION_STRING --env production --body "Server=prod-db.database.windows.net;..."

# Repository variables
gh variable set APP_NAME --body "contoso-api"
gh variable set AZURE_RESOURCE_GROUP --body "contoso-rg"

# Environment variables
gh variable set APP_SERVICE_PLAN --env staging --body "contoso-plan-staging"
gh variable set APP_SERVICE_PLAN --env production --body "contoso-plan-prod"

Exercícios de quebra e conserto​

Exercício 1: Corrigir o workflow com falha​

O workflow a seguir contém erros. Identifique e corrija-os:

name: Broken Workflow

on:
  push:
    branches: main    # ERROR 1: Should be an array [main]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Set output
        run: echo "result=success" >> $GITHUB_OUTPUT  # ERROR 2: Missing id field

      - name: Use output
        run: echo ${{ steps.set-output.outputs.result }}  # ERROR 3: step id doesn't match

  deploy:
    needs: build
    runs-on: ubuntu-latest
    environment: production
    steps:
      - name: Deploy
        uses: azure/webapps-deploy@v3
        with:
          app-name: ${{ env.APP_NAME }}  # ERROR 4: env context not available, use vars
          images: ${{ needs.build.outputs.image }}  # ERROR 5: build job has no outputs defined

Versão corrigida:

name: Fixed Workflow

on:
  push:
    branches: [main]

jobs:
  build:
    runs-on: ubuntu-latest
    outputs:
      image: ${{ steps.set-output.outputs.result }}
    steps:
      - uses: actions/checkout@v4

      - name: Set output
        id: set-output
        run: echo "result=success" >> $GITHUB_OUTPUT

      - name: Use output
        run: echo ${{ steps.set-output.outputs.result }}

  deploy:
    needs: build
    runs-on: ubuntu-latest
    environment: production
    steps:
      - name: Deploy
        uses: azure/webapps-deploy@v3
        with:
          app-name: ${{ vars.APP_NAME }}
          images: ${{ needs.build.outputs.image }}

Exercício 2: Depurar o problema de permissões​

Um workflow que faz push para o GHCR falha com denied: permission_denied. O arquivo de workflow contém:

permissions:
  contents: read
Mostrar solução

Correção: Adicione a permissão packages: write para permitir push para o GHCR:

permissions:
  contents: read
  packages: write

Verificação de conhecimento​

1. No GitHub Actions, qual é a maneira correta de passar dados entre jobs?

2. Qual configuração de trigger permite execução manual do workflow com parâmetros customizados?

3. Qual é a principal vantagem de uma composite action sobre um reusable workflow?

4. Qual valor de 'permissions' é necessário para que um workflow faça push de imagens de contêiner para o GitHub Container Registry (ghcr.io)?

Limpeza​

# Remove the test workflow runs (optional)
gh run list --workflow=ci-cd.yml --limit 5 --json databaseId --jq '.[].databaseId' | \
  xargs -I {} gh run delete {}

# Delete environment if no longer needed
gh api --method DELETE repos/{owner}/{repo}/environments/staging
gh api --method DELETE repos/{owner}/{repo}/environments/production

# Remove GHCR images
gh api --method DELETE /user/packages/container/contoso-api/versions/{version_id}