GitHub Action Core Components

Automate your software development lifecycle by leveraging GitHub Actions’ three main building blocks—workflows, jobs, and steps. In this guide, you’ll learn how they fit together to build, test, and deploy your applications seamlessly.

Example Workflow

Below is a sample workflow YAML stored under .github/workflows/ in your repository:

name: My Awesome App
on: 
  push:
    branches:
      - main

jobs:
  unit-testing:
    name: Unit Testing
    runs-on: ubuntu-latest

    steps:
      - name: Checkout Repository
        uses: actions/checkout@v3

      - name: Setup Node.js
        uses: actions/setup-node@v3
        with:
          node-version: '20'

      - name: Install Dependencies
        run: npm install

      - name: Execute Unit Tests
        run: npm test

Note

Save each workflow file in the .github/workflows/ directory. You can have multiple workflow files, each triggered by different events (e.g., pull_request, release, or a schedule).

1. Workflows

A workflow is a configurable automated process defined by a YAML file. It listens for one or more events in your repository and runs one or more jobs.

Key elements in the example above:

name: My Awesome App
A custom label visible in the Actions tab.
on: push
Defines the event(s) that trigger the workflow. You can specify multiple events and filters.

You can also trigger workflows via:

pull_request
schedule (cron jobs)
workflow_dispatch (manual run)

For more triggers, see Events that trigger workflows.

2. Jobs

A job is a collection of steps executed on the same runner. By default, jobs run in parallel, but you can coordinate them using dependencies.

jobs:
  unit-testing:
    name: Unit Testing
    runs-on: ubuntu-latest
    steps:
      # Individual steps go here...

Job identifier (unit-testing): used to set dependencies.
runs-on: selects the runner environment (ubuntu-latest, windows-latest, etc.).

Warning

If you need to share data between jobs, use artifacts or caches.

3. Steps

Within each job, steps define individual tasks. They execute sequentially on the same runner.

Use uses to invoke an action.
Use run to execute shell commands.

steps:
  - name: Checkout Repository
    uses: actions/checkout@v3

  - name: Setup Node.js
    uses: actions/setup-node@v3
    with:
      node-version: '20'

  - name: Install Dependencies
    run: npm install

  - name: Execute Unit Tests
    run: npm test

Checkout Repository: Fetches your code.
Setup Node.js: Installs Node.js and npm.
Install Dependencies: Runs npm install.
Execute Unit Tests: Runs your test suite.

4. Actions

An action is a reusable, shareable unit of automation. Use community or official actions from the GitHub Marketplace. You can also author custom actions.

Resource Type	Description	Example
Build & Push Docker Images	Constructs and publishes Docker images to a registry	`docker/build-push-action@v3`
Create AKS Clusters	Provisions Azure Kubernetes Service clusters	`Azure/aks-set-context@v1`
Consume Vault Secrets	Fetches secrets from Vault and exposes them as environment vars	`hashicorp/vault-action@v2`

The image outlines a three-step GitHub Actions process: building and pushing Docker images, creating an AKS cluster, and consuming Vault secrets.

Getting Started

Create .github/workflows/ci.yml in your repo.
Define your on triggers.
Add jobs and steps to build, test, and deploy.

With these core components in place, you’re ready to harness the full power of GitHub Actions for continuous integration and continuous delivery.

References

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