🚀 Day 38: GitHub Actions Caching Strategies – Speed Up Your CI/CD!

Welcome to Day 38 of my #100DaysOfDevOps!
Today, we’re diving into GitHub Actions caching to supercharge your CI/CD workflows by caching dependencies with actions/cache@v4. Let’s make those builds lightning fast! ⚡ #DevOps #GitHubActions

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📦 What Is Caching in GitHub Actions?

Reinstalling dependencies like node_modules in every CI/CD run is time-consuming. With GitHub Actions caching, you can store and reuse these dependencies across runs, slashing build times and making your workflows more efficient. 🚀 #CI/CD #Automation

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📁 Project Structure

Here’s how your project should look:

caching-demo/
│
├── app.js             # Simple JS app
├── app.test.js        # Jest test file
├── package.json       # Includes Jest
└── .github/
    └── workflows/
        └── nodejs.yml # GitHub Actions Workflow

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🛠️ Step 1: Initialize the Project

Set up the project and install Jest:

mkdir caching-demo && cd caching-demo
npm init -y
npm install --save-dev jest

#NodeJS #Jest

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🧪 Step 2: Add Code + Test

app.js

Create a simple function to test:

function add(a, b) {
  return a + b;
}
module.exports = add;

app.test.js

Write a Jest test for the add function:

const add = require('./app');

test('adds 1 + 2 to equal 3', () => {
  expect(add(1, 2)).toBe(3);
});

Update package.json

Ensure your package.json includes the test script and Jest dependency:

{
  "name": "caching-demo",
  "version": "1.0.0",
  "main": "app.js",
  "scripts": {
    "test": "jest"
  },
  "devDependencies": {
    "jest": "^30.0.5"
  }
}

#JavaScript #Testing

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⚙️ Step 3: Add GitHub Actions Workflow

Create the workflow file at .github/workflows/nodejs.yml:

name: Node.js Caching Demo

on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node-version: [14.x, 16.x, 18.x]

    steps:
      - name: 📥 Checkout code
        uses: actions/checkout@v4

      - name: 🔧 Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node-version }}

      - name: 📦 Cache npm dependencies
        uses: actions/cache@v4
        with:
          path: ~/.npm
          key: Linux-node-${{ hashFiles('**/package-lock.json') }}
          restore-keys: |
            Linux-node-

      - name: 📥 Install dependencies
        run: npm ci

      - name: 🧪 Run tests
        run: npm test

#GitHubActions #Caching

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🚀 Step 4: Push to GitHub

Push your project to GitHub:

git init
git remote add origin https://github.com/ritesh355/caching-demo.git
git add .
git commit -m "Add caching demo with Jest and GitHub Actions"
git push -u origin main

#Git #VersionControl

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🧪 Step 5: Check Workflow and Cache

1. Go to your GitHub repo → Actions tab.

2. Watch the Node.js Caching Demo workflow run across Node versions 14.x, 16.x, and 18.x.

First Run (Cache Miss)

Output:

Cache not found for input keys: Linux-node-...
Run npm ci
Installed packages...

Result:

• Dependencies installed from scratch.

• Cache created and saved for future runs.

Second Run (Cache Hit)

Output:

Cache hit for: Linux-node-eab9f1a5...
Cache restored successfully
Run npm ci

Result:

• Cache restored from ~/.npm.

• Dependencies not re-downloaded.

• 🚀 Tests run faster!

#WorkflowOptimization #CI/CD

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🔍 How to Check Cache Status

In the GitHub Actions logs, look under the Cache npm dependencies step:

• ✅ Cache hit: Cache was reused, speeding up the build.

• ❌ Cache not found: A new cache was created.

#Debugging #Logs

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✅ Final Output

After running tests:

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Time:        ~0.1s

Benefits:

• ✔️ Faster builds.

• ✔️ Reduced external API calls.

• ✔️ Smarter workflows.

#Efficiency #Automation

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📚 What I Learned

• How to use actions/cache@v4 to persist ~/.npm or node_modules across jobs.

• Using the hash of package-lock.json for reliable cache keys.

• Caching significantly speeds up CI/CD pipelines.

• Debugging cache hits/misses in GitHub Actions logs.

#Learning #DevOpsJourney

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🔗 My Work

• 📘 GitHub Repo

• ✍️ Hashnode Blog

• 🔗 LinkedIn

#Portfolio #Networking

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🎉 Congratulations!

You’ve mastered GitHub Actions caching to optimize your CI/CD pipeline! Keep pushing the boundaries of your DevOps skills! 💪 #100DaysOfDevOps #KeepLearning

Need help? Drop a comment or question, and I’ll guide you through any issues!