Introduction to GitHub Actions

Introduction to GitHub Actions

GitHub Actions is GitHub's repository-native automation platform. It connects an event—such as a push, pull request, release, schedule, or manual request—to a workflow made of jobs. Teams use it for continuous integration, controlled delivery, releases, dependency maintenance, and repository operations.

Core ideas

• Continuous integration (CI) validates small, frequent changes through repeatable builds and checks.
• Continuous delivery keeps a verified artifact ready to release; continuous deployment also releases it automatically.
• A workflow is versioned with the application in .github/workflows, so automation changes receive the same review as code.
• Every trigger creates a workflow run. A run contains one or more jobs, and each job executes steps on a runner.

How it works

A practical first pipeline checks out the exact commit, installs dependencies reproducibly, and runs a deterministic validation command. A failing step normally fails its job and blocks dependent jobs. Branch protection can require the resulting check before a pull request merges.

Configuration example

name: CI
on:
  pull_request:
  push:
    branches: [main]

jobs:
  validate:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 22
          cache: npm
      - run: npm ci
      - run: npm run build

Read the example from top to bottom: the trigger creates a run, the job requests a runner, and each step receives only the context configured for it. Adapt names, versions, permissions, and commands to the repository rather than copying production credentials or policies blindly.

Production guidance

• Give workflows and jobs meaningful names because they appear in checks and run history.
• Separate validation from deployment, then protect deployment with environments and approvals.
• Treat workflow code as production code: review it, restrict permissions, and investigate unexpected changes.

The chapter quiz follows this lesson and checks both the vocabulary and the operational decisions behind the configuration.