Know your github actions

Absolutely! Let's build a concise and practical cheat sheet for GitHub Actions, focusing on the most commonly used terms and concepts.

GitHub Actions Cheat Sheet

Core Concepts:

• Workflow:

  • A configurable automated process that will run one or more jobs. Defined in a YAML file (.github/workflows/*.yml).

• Job:

  • A set of steps that execute on the same runner. Runs in parallel by default.

• Step:

  • An individual task that can run commands or actions.

• Action:

  • A reusable unit of code. Can be a community-created action or a custom action.

• Runner:

  • A server that runs your workflows. Can be GitHub-hosted or self-hosted.

• Event:

  • A trigger that starts a workflow (e.g., push, pull_request, schedule).

• Artifacts:

  • Files generated during a workflow that can be stored and downloaded.

• Secrets:

  • Encrypted environment variables used to store sensitive information.

Workflow File Structure (YAML):

YAML

name: My Workflow Name on: # Triggers push: branches: - main pull_request: jobs: build: runs-on: ubuntu-latest # Runner type steps: - name: Checkout code uses: actions/checkout@v3 # Action usage - name: Set up Node.js uses: actions/setup-node@v3 with: node-version: '18' - name: Install dependencies run: npm install # Shell command - name: Build run: npm run build - name: Run tests run: npm test - name: Deploy if: github.ref == 'refs/heads/main' # Conditional execution run: | echo "Deploying to production..." # Deployment commands       - name: Upload Artifacts uses: actions/upload-artifact@v3 with: name: build-artifacts path: build/

Key Terms and Phrases:

• name:: Workflow or job name.

• on:: Specifies events that trigger the workflow.

• jobs:: Defines the jobs to be executed.

• runs-on:: Specifies the runner environment.

• steps:: Defines the sequence of steps within a job.

• uses:: Specifies an action to use.

• run:: Executes shell commands.

• with:: Provides input parameters to an action.

• env:: Sets environment variables.

• secrets:: Accesses stored secrets.

• if:: Conditional execution of a step.

• needs:: Defines dependencies between jobs.

• strategy:: Defines a matrix of job configurations.

• permissions:: Grants permissions to the GITHUB_TOKEN.

• timeout-minutes:: Specifies the maximum execution time for a job.

• continue-on-error:: Allows a job to continue even if a step fails.

• GITHUB_TOKEN:: A token automatically provided by GitHub Actions.

• github.ref: The branch or tag that triggered the workflow.

• github.event_name: The name of the event that triggered the workflow.

• github.workspace: The default working directory.

Categories of Actions (Commonly Used):

• Version Control:

  • actions/checkout@v3: Checks out your repository.

  • actions/upload-artifact@v3: Uploads artifacts.

  • actions/download-artifact@v3: Downloads artifacts.

• Language/Environment Setup:

  • actions/setup-node@v3: Sets up Node.js.

  • actions/setup-python@v4: Sets up Python.

  • actions/setup-java@v3: Sets up Java.

  • actions/setup-dotnet@v3: Sets up .NET.

  • actions/setup-go@v4: Sets up Go.

• Build/Test/Deployment:

  • (Custom scripts using run:) Build, test, and deployment commands.

  • Third party deployment actions for cloud providers (AWS, Azure, GCP, etc.)

• Notifications/Integrations:

  • Actions for sending Slack, Discord, or email notifications.

  • Actions for integrating with external tools (e.g., SonarCloud, Codecov).

• Security:

  • Actions for static analysis security testing (SAST)

  • Actions for secret scanning.

• Docker:

  • docker/build-push-action@v5: Builds and pushes Docker images.

  • docker/login-action@v3: Logs in to Docker registries.

• Caching:

  • actions/cache@v3: Caches dependencies.

Tips for Effective Usage:

• Use the GitHub Actions Marketplace to find reusable actions.

• Leverage if: conditions to control step execution.

• Use secrets: to store sensitive information securely.

• Use strategy: matrix: for parallel testing across multiple configurations.

• Test workflows locally using act.

• Break down large workflows into smaller, more manageable jobs.

• Use comments in your YAML files to document your workflow.

Example of using secrets:

YAML

steps: - name: Deploy to production run: | deploy.sh --api-key ${{ secrets.PRODUCTION_API_KEY }}

Example of using matrix:

YAML

jobs: test: runs-on: ubuntu-latest strategy: matrix: node-version: ['16', '18', '20'] steps: - name: Checkout code uses: actions/checkout@v3 - name: Set up Node.js ${{ matrix.node-version }} uses: actions/setup-node@v3 with: node-version: ${{ matrix.node-version }} - name: Install dependencies run: npm install - name: Run tests run: npm test

This cheat sheet should provide a solid foundation for working with GitHub Actions. Remember to refer to the official GitHub Actions documentation for the most up-to-date information.