Tickets Reservation Engine

A professional high-performance NestJS-based backend for high-concurrency ticket booking and real-time inventory management.

🏗️ Architecture Overview

The project follows a modular architecture designed for scalability and maintainability:

• src/common: Project-wide utility types, decorators, and centralized enums (e.g., NodeEnv, LogLevel). Always use these shared constants.
• src/core: The infrastructure backbone. Managed by the CoreModule, it handles all non-business concerns (Config, DB, Redis, Logging).
• src/modules: (Under development) Will contain business-specific modules (Users, Events, Bookings, Payments).

🚀 Core Infrastructure

All infrastructure logic is encapsulated within the CoreModule and its specialized sub-modules:

Sub-module	Purpose	Global?
Config	Robust environment validation (via Joi) and namespaced configurations.	✅
Database	Managed MongoDB connection and base abstract repositories for DAL.	❌
Redis	High-performance ioredis client for distributed locking and caching.	✅
Logger	Mandatory structured Wide-Event logging system.	✅

Using Core Services

Since most core modules are global, you can inject their services directly into any provided class:

constructor(private readonly appConfig: AppConfig) {}

📝 Logging Strategy

Strict Requirement: Every log in the system must use the LoggingService (exported via LoggerModule).

Why?

Unlike default string-based loggers, this service persists Structured Wide Events to MongoDB. This enables complex auditing, performance tracking, and troubleshooting without manual log parsing.

How to Use

Always inject LoggingService or use it as the default NestJS logger:

// 1. Context logging (simulating standard logger)
this.logger.log('Payment processed', 'PaymentsService');

// 2. Structured logging (Mandatory for critical paths)
this.logger.warn(
  'Inventory threshold reached',
  {
    action: 'LOW_INVENTORY_DETECTED',
    eventId: 'evt_123',
    metadata: { stockLeft: 5 },
  },
  'InventoryService',
);

🛠️ Project Setup

1. Prerequisites

• Node.js v20.17+
• Docker & Docker Compose

2. Infrastructure

Spin up the required infrastructure (Redis) using Docker Compose:

docker-compose up -d

3. Installation

npm install

4. Running

# Development (with watch mode)
npm run start:dev

# Production
npm run build
npm run start:prod

🧪 Verification

# Unit tests
npm test

# E2E tests
npm run test:e2e

📜 License

Unlicensed (Private Project)