GitHub Actions is a powerful tool that enables developers to automate workflows, test code, and deploy projects on the GitHub platform. By providing a simple way to automate repetitive tasks, GitHub Actions has revolutionized the way developers work, and has made it easier than ever to manage code repositories.
GitHub Actions works by defining workflows, which are a set of automated tasks that are triggered by certain events. For example, you can set up a workflow to run tests every time code is pushed to a repository, or to deploy a project to a production server when a new release is tagged. Workflows are defined using YAML syntax, which is a simple and human-readable format that is easy to understand and edit.
The basic structure of a workflow is as follows:
name: Workflow Name
on: [event]
jobs:
job-name:
runs-on: [platform]
steps:
- name: Step Name
uses: action-name@version
with:
parameter-name: parameter-value
Let’s break this down:
- The
namefield is used to give the workflow a name. - The
onfield specifies the event that will trigger the workflow. This can be a push to a branch, a pull request, a scheduled event, or a custom event. - The
jobsfield contains one or more jobs that will be run as part of the workflow. - Each job has a
namefield, which is used to give the job a name. - The
runs-onfield specifies the platform that the job will run on. This can be a specific operating system or a virtual environment. - The
stepsfield contains one or more steps that will be run as part of the job. - Each step has a
namefield, which is used to give the step a name. - The
usesfield specifies the action that will be run as part of the step. An action is a reusable unit of code that performs a specific task, such as running tests or deploying code. - The
withfield specifies any parameters that need to be passed to the action.
GitHub Actions comes with a wide variety of pre-built actions that can be used to perform common tasks, such as running tests, deploying code, and sending notifications. These actions can be found in the GitHub Marketplace, which is a library of reusable workflows and actions that can be used to streamline development workflows.
Using GitHub Actions, you can easily create a workflow that tests your code every time it is pushed to a repository. Here’s an example workflow that does just that:
name: Test
on: [push]
jobs:
build:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- name: Run Tests
run: |
npm install
npm test
This workflow has a single job called build that runs on the latest version of Ubuntu. The steps field contains two steps: the first step checks out the repository, and the second step installs the necessary dependencies and runs the tests.
GitHub Actions can also be used to deploy code to a production server. Here’s an example workflow that deploys a Node.js application to a Heroku server:
name: Deploy
on:
release:
types: [created]
jobs:
deploy:
runs-on: ubuntu-latest
steps:
- name: Checkout Code
uses: actions/checkout@v2
- name: Setup Node.js
uses: actions/setup-node@v2
with:
node-version: '14.x'
- name: Install Dependencies
run: npm install
- name: Deploy to Heroku