GitHub Actions Introduction

GitHub Actions is an automation platform integrated with GitHub repositories. It allows developers to create workflows that run automatically in response to repository events.

GitHub Event
     ↓
Workflow
     ↓
Jobs
     ↓
Steps
     ↓
Result

GitHub Actions can reduce repetitive manual work by automating development tasks.

• Run tests
• Build applications
• Check code
• Deploy applications
• Publish packages
• Automate workflows
• Perform scheduled tasks

A common workflow is to run tests whenever code is pushed.

Developer
    ↓
git push
    ↓
GitHub
    ↓
GitHub Actions
    ↓
Run Tests
    ↓
Pass / Fail

A workflow is an automated process defined in a YAML file inside the repository.

.github/
└── workflows/
    └── test.yml

A workflow contains instructions describing when and how automation should run.

GitHub Actions workflow files are normally stored in:

.github/workflows/

For example:

.github/workflows/ci.yml

The workflow file uses YAML syntax.

name: CI

on:
  push:

jobs:
  test:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v4

      - run: echo "Running tests"

This workflow runs when a push event occurs and then executes the defined job.

The name property gives a workflow a readable name.

name: My CI Workflow

The name helps developers identify the workflow in the GitHub Actions interface.

An event determines when a workflow should run.

Common examples include:

• push
• pull_request
• workflow_dispatch
• schedule
• Other supported GitHub events

on:
  push:

The push event can trigger a workflow when commits are pushed to the repository.

on:
  push:

This is commonly used for automated testing and build processes.

The pull_request event can trigger automation when a pull request is created or updated.

on:
  pull_request:

This is useful for automatically checking proposed changes.

A workflow can also be configured for manual execution using workflow_dispatch.

on:
  workflow_dispatch:

This allows an authorized user to start the workflow manually from GitHub.

GitHub Actions can also run workflows on a schedule using a cron expression.

on:
  schedule:
    - cron: '0 0 * * *'

Scheduled workflows are useful for recurring automation tasks.

A workflow contains one or more jobs. A job is a group of steps that runs as a unit.

jobs:
  test:
    ...
  build:
    ...

A workflow can contain multiple jobs.

Each job has an identifier.

jobs:
  test:

Here, test is the job ID.

Another example:

jobs:
  build:
    ...

A runner is the environment in which a GitHub Actions job executes.

runs-on: ubuntu-latest

The runner provides the environment needed to execute the job's steps.

A commonly used runner is:

runs-on: ubuntu-latest

The appropriate runner depends on the requirements of the project and workflow.

A job contains one or more steps. Steps perform the actual tasks of the job.

jobs:
  test:
    runs-on: ubuntu-latest

    steps:
      - run: echo "Hello"
      - run: echo "Testing"

The run keyword executes a shell command.

- run: echo "Hello GitHub Actions"

Commands can be used to install dependencies, run tests, build projects, or perform other tasks.

An action is a reusable unit of automation that can perform a particular task.

- uses: actions/checkout@v4

The uses keyword allows a workflow to use an existing action.

The checkout action is commonly used to make the repository's source code available to the workflow.

- uses: actions/checkout@v4

After checkout, later steps can work with the repository files.

A workflow can install project dependencies before running tests or building an application.

steps:
  - uses: actions/checkout@v4

  - run: npm install

  - run: npm test

The exact commands depend on the programming language and project.

GitHub Actions can automatically run tests after code is pushed or a pull request is updated.

steps:
  - uses: actions/checkout@v4
  - run: npm install
  - run: npm test

If the test command fails, the workflow can report a failed result.

Workflows can also build applications automatically.

steps:
  - uses: actions/checkout@v4
  - run: npm install
  - run: npm run build

Build commands depend on the project's technology and configuration.

Jobs can be configured so that one job depends on another job.

jobs:

  test:
    ...

  build:
    needs: test
    ...

Here, the build job depends on the test job.

Continuous Integration (CI) involves frequently integrating code changes and automatically checking them.

Push Code
   ↓
Workflow
   ↓
Install Dependencies
   ↓
Run Tests
   ↓
Build
   ↓
Result

GitHub Actions can also be used to automate deployment processes.

Code
 ↓
Test
 ↓
Build
 ↓
Deploy

Deployment steps depend on the hosting platform and project configuration.

name: Node.js CI

on:
  push:
  pull_request:

jobs:
  test:

    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v4

      - run: npm install

      - run: npm test

This example checks the project whenever the configured events occur.

Repository
    ↓
GitHub Event
    ↓
Workflow Starts
    ↓
Runner
    ↓
Job
    ↓
Checkout Code
    ↓
Install Dependencies
    ↓
Run Tests
    ↓
Build
    ↓
Result

• Keep workflows focused.
• Use clear workflow and job names.
• Run automated tests.
• Use appropriate actions.
• Keep action versions maintained.
• Protect sensitive values.
• Use secrets for sensitive credentials.
• Review workflow permissions.
• Keep commands easy to understand.
• Check workflow results regularly.

GitHub Actions provides automation directly inside GitHub repositories. Workflows are defined using YAML files and can run automatically in response to repository events.

Event
 ↓
Workflow
 ↓
Job
 ↓
Runner
 ↓
Steps
 ↓
Action / Command
 ↓
Result

GitHub Actions can be used for continuous integration, testing, building, deployment, scheduled tasks, and many other development automation processes.