Feat(Docker): Add Production-Ready Multi-Stage Docker Setup

[AnubhavGitHub07]

Description

Production-ready multi-stage Docker setup for Codelabz with separate development and production environments.

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Changes

File	Purpose
Dockerfile	3-stage multi-stage build (deps → builder → nginx:alpine) — 102MB final image
Dockerfile.dev	Dev environment with Node 18 + JRE for Firebase Emulators
docker-compose.yml	Production compose with build args, health check, restart policy
docker-compose.dev.yml	Dev compose with hot-reload volumes & emulator ports
nginx.conf	SPA routing, gzip compression, security headers, asset caching
.dockerignore	~60 exclusion patterns for build context optimization
scripts/entrypoint.sh	Dev container startup (emulators + Vite)
DOCKER.md	Setup instructions, commands, troubleshooting guide

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Motivation and Context

The existing Docker setup had critical issues:

1. Node 14 (EOL) — no security updates
2. ~1.2GB image — single-stage build with all dev dependencies
3. Vite dev server in production — not production-ready
4. No documentation — no setup instructions for contributors

This PR replaces it with a multi-stage build using Nginx for production serving, upgrades runtime to Node 18, and provides separate dev/prod environments with comprehensive documentation.

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How Has This Been Tested?

Production Build

docker build -t codelabz:production .

✅ Exit code: 0
✅ Image size: 102MB
✅ Build time: ~130s

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Production Run

docker run -d -p 8080:80 --name codelabz-test codelabz:production

✅ HTTP 200 at http://localhost:8080

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Health Check

docker inspect --format='{{.State.Health.Status}}' codelabz-test

Result:

healthy

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Security Headers Verification

curl -sI http://localhost:8080/

Verified headers:

• X-Frame-Options
• X-Content-Type-Options
• X-XSS-Protection
• Referrer-Policy

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No Source Code in Production Image

docker run --rm codelabz:production ls /usr/share/nginx/html/

✅ Only static assets present
❌ No node_modules
❌ No src
❌ No .env

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Development Compose

docker compose -f docker-compose.dev.yml up --build

✅ Vite dev server running at :5173
✅ Firebase Emulators running

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Testing Environment

• macOS
• Docker Desktop
• Docker Compose v2

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Testing Screenshots

1. Production Image Build (Multi-Stage)

2. Image Size — 102MB

3. Container Running — Health Check Verified

4. No Source Code in Production Image

5. Security Headers Present

6. Application Served via Nginx ( Port : 8080 )

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Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

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Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[github-actions]

Visit the preview URL for this PR (updated for commit d694718):

https://codelabz-anubhav--pr-7-bh8ukm81.web.app

_{(expires Mon, 16 Mar 2026 21:27:39 GMT)}

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_{Sign: daeac1a46194ebcbfcb5f24f714b8354e16dd037}