What is GitHub Actions?

💡 CI/CD Tool Study

GitHub Actions

GitHub Actions is a continuous integratoin and continuous delivery (CI/CD) platform that allows to automate the build, test, and deployment pipeline.

The components of GitHub Actions

• Workflows: A configurable automated process that will run one or more jobs.
  • YAML file.
  • Can be triggered by an event in the repository, or manually, or at a defined schedule.
  • Defined in the .github/workflows directory in a repository.
• Events: A specific activity that triggers a workflow run.
  • Examples:
    • A pull request is created
    • An issue is open
    • A commit is pushed
    • Run on a schedule
    • Posting to a REST API
    • Manually
• Jobs: A set of steps that execute on the same runner.
  • Each step is either a shell script, or an action that will be run.
  • Steps are executed in order and are dependent on each other.
  • Steps share data from one to another.
    • Example:
      • Step_1 - builds an application.
      • Step_2 - tests the application.
  • Jobs run in parallel and have no dependencies by default.
    • If a job takes a dependency on another job, it will wait for the dependent job to complete before it can run.
• Actions: A custom application for the GitHub Actions platform that performs a complex but frequently repeated task.
  • Help reduce the repetitive code in the workflow files.
  • Example:
    • Pull a git repository,
    • Set up the correct toolchain for the build environment,
    • Set up the authentication to the cloud provider.
• Runners: A server that runs the workflows when they’re triggered.
  • Ubuntu Linux, Microsoft Windows, and macOS runners in a newly-provisioned virtual machine.
  • Hosting the user own runners is possible.

Example workflow

name: learn-github-actions
on: [push]
jobs:
  check-bats-version:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-node@v3
        with:
          node-version: '14'
      - run: npm install -g bats
      - run: bats -v

• name: learn-github-actions - The name of the workflow that will appear in the Actions tab.
• on: [push] - Specifies the trigger for this workflow.
• jobs: - Group of the jobs in the workflow.
• check-bats-version: - The name of a job.
• runs-on: ubuntu-latest - Configuration. Run on the latest version of an Ubuntu Linux runner.
• steps: - Group of the steps in the job.
• - uses: actions/checkout@v3 - Run v3 of the actions/checkout action.
• - run: npm install -g bats - Execute a command on the runner.

(Reference: GitHub Docs https://docs.github.com/en/actions/learn-github-actions/understanding-github-actions)