Inventory Backend Service

Minimal Node.js/Express backend for inventory management. Focus: DevOps/CI-CD demo, not application complexity.

Features (Minimal by Design)

• 4 API endpoints: GET/POST items, health check, readiness check
• MySQL database with single table (4 fields)
• Input validation
• CORS and security headers
• Non-root Docker container

Tech Stack

• Node.js 20
• Express 4
• MySQL 8.0
• mysql2 (prepared statements for SQL injection protection)
• helmet (security headers)
• express-validator

Local Development

Prerequisites

• Node.js 20+
• MySQL 8.0 running locally or via Docker

Quick Start

# 1. Start MySQL
docker run -d \
  --name mysql-local \
  -e MYSQL_ROOT_PASSWORD=rootpass \
  -e MYSQL_DATABASE=inventory \
  -p 3306:3306 \
  mysql:8.0

# 2. Install dependencies
npm install

# 3. Create .env file
cp .env.example .env

# 4. Start server
npm start
# Or with hot-reload:
npm run dev

Testing

# Run tests
npm test

# Run linter
npm run lint

API Endpoints

Health Check (Liveness)

curl http://localhost:3000/health
# Response: {"status": "ok"}

Readiness Check

curl http://localhost:3000/ready
# Response: {"status": "ready", "database": "connected"}

Get All Items

curl http://localhost:3000/api/items
# Response: [{"id":1,"name":"Laptop","quantity":10,"price":"999.99"},...]

Create Item

curl -X POST http://localhost:3000/api/items \
  -H "Content-Type: application/json" \
  -d '{"name":"Monitor","quantity":15,"price":299.99}'
# Response: {"id":4,"name":"Monitor","quantity":15,"price":299.99,"message":"Item created successfully"}

Docker Build

# Build image
docker build -t backend-service:latest .

# Run container
docker run -d \
  -p 3000:3000 \
  -e DB_HOST=host.docker.internal \
  -e DB_PASSWORD=rootpass \
  backend-service:latest

CI/CD Pipeline

Gitea Actions workflow:

1. Checkout → Install → Lint → Test
2. SonarQube scan + quality gate
3. Build multi-stage Docker image
4. Push to Gitea registry with tags: {branch}-{sha}, {branch}, latest
5. Update k8s-manifests repo

Database Schema

CREATE TABLE items (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(255) NOT NULL,
    quantity INT NOT NULL DEFAULT 0,
    price DECIMAL(10, 2) NOT NULL
);

That's it! No timestamps, no foreign keys, no complexity. Focus on CI/CD.

Environment Variables

Variable	Default	Description
PORT	3000	Server port
DB_HOST	localhost	MySQL host
DB_PORT	3306	MySQL port
DB_USER	root	MySQL user
DB_PASSWORD	rootpass	MySQL password
DB_NAME	inventory	Database name

Security

• ✓ Non-root Docker user (nodejs:1001)
• ✓ Helmet.js security headers
• ✓ SQL injection protection (prepared statements)
• ✓ Input validation (express-validator)
• ✓ CORS configured
• ✓ Multi-stage Docker build (no dev dependencies in prod)

Project Structure

backend-service/
├── src/
│   ├── server.js      # Main Express app (~100 lines, all routes inline)
│   ├── db.js          # MySQL connection pool
│   └── init.sql       # Database schema
├── tests/
│   └── server.test.js # Basic API tests
├── .gitea/workflows/
│   └── ci.yaml        # CI/CD pipeline
├── Dockerfile         # Multi-stage build
├── package.json
└── README.md

Total: ~10 files - intentionally minimal!