Git GitHub Actions Introduction
In this page:
What is GitHub Actions?
GitHub Actions is an automation platform built directly into GitHub. It lets you automate software development workflows like testing, building, and deploying your code. Every workflow is triggered by an event, such as pushing new code to your repository.
Example: What is GitHub Actions?
# .github/workflows/ci.yml
name: CI
on: pushDefining a Workflow File
Workflows are written as YAML files inside .github/workflows/, and each one declares a name plus an on: key specifying what event triggers it. GitHub picks up any correctly formatted file in that directory automatically — no separate registration step needed.
Example: Defining a Workflow File
name: CI
on:
push:
branches: [main]Understanding Events
Events are what start a workflow run — push, pull_request, schedule (cron syntax for timed runs), and workflow_dispatch (a manual trigger button) are the most common. A workflow can listen for several event types at once and even filter by branch or file path.
Example: Understanding Events
on:
push:
pull_request:
schedule:
- cron: "0 0 * * *"
workflow_dispatch:Jobs and Steps
A workflow is made of one or more jobs, and by default GitHub runs them all in parallel on separate virtual machines — you use needs: to force one job to wait for another. Within a job, steps run sequentially, top to bottom, on the same machine.
Example: Jobs and Steps
jobs:
test:
runs-on: ubuntu-latest
steps:
- run: npm test
deploy:
needs: test
runs-on: ubuntu-latestUsing Pre-built Actions
You do not have to write all commands from scratch. You can import pre-built, community-maintained actions using the uses keyword to handle complex tasks like checking out your code or setting up environments.
Example: Using Pre-built Actions
steps:
- uses: actions/checkout@v4
- uses: actions/setup-node@v4Chapter Quiz — Complete all 5 topics to unlock
0/5 topics done
Complete these topics first: