Jobs & Steps

Parallel Execution

Steps can run in parallel using the strategy key, which is a job-level configuration. This allows you to define multiple job runs with different parameters.

Example: Parallel Job with Strategy

jobs:
  build-and-test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        os: [ubuntu-latest, windows-latest]
        node: [18, 20]
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
      - name: Setup Node.js
        uses: actions/setup-node@v3
        with:
          node-version: ${{ matrix.node }}
      - name: Run tests
        run: npm test

Note: The strategy key must be placed at the job level, not under steps. Matrix strategies define how a job splits into multiple parallel runs based on specified parameters (e.g., OS, Node.js versions).

Conditional Logic for Workflow Control

Use if: conditions to control whether steps or jobs execute based on dynamic criteria. Conditions evaluate expressions that determine workflow flow.

Example: Conditional Step Based on Environment Variable

steps:
  - name: Run tests if DEBUG is set
    if: ${{ env.DEBUG }}
    run: npm test

Example: Conditional Job Based on Branch

jobs:
  deploy:
    if: ${{ github.ref == 'refs/heads/main' }}
    runs-on: ubuntu-latest
    steps:
      - name: Deploy application
        run: ./deploy.sh

Key Concepts:
- Use $ to reference variables, job status, or context values.}
- Combine conditions with logical operators (&&, ||, !) for complex rules.
- Conditional logic enables workflows to skip steps/jobs, reroute execution, or adapt to runtime inputs.