Notification & User Services

This project contains two microservices: User Service and Notification Service. They communicate via RabbitMQ to handle user-related events and send notifications (email, push, SMS). PostgreSQL is used for data storage in the User Service.

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🚀 Overview

• User Service: Manages user operations and publishes notification events.
• Notification Service: Listens to events and sends notifications.
• RabbitMQ: Message broker for asynchronous event communication.
• PostgreSQL: Database for User Service.

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🛠️ Technologies

• NestJS (TypeScript)
• RabbitMQ
• PostgreSQL 16
• Docker & Docker Compose
• Axios (used in Notification Service to simulate push notifications)

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⚙️ Running Locally with Docker Compose

Services

Service	Description	Ports
postgres	PostgreSQL database	5432:5432
rabbitmq	RabbitMQ broker and management UI	5672:5672, 15672:15672
user-service	User microservice API and event publisher	3000:3000
notification-service	Notification microservice (consumer and sender)	5000:5000

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Setup and Start

1. Clone the repository:

   git clone <your-repo-url>
   cd <your-repo>

2. Create .env files:

   cp ./user-service/.env.example ./user-service/.env

   cp ./notification-service/.env.example ./notification-service/.env

3. Start all services:

   docker-compose up --build

4. Access the services:

   • User Service API: http://localhost:3000
   • Notification Service API: http://localhost:5000
   • RabbitMQ Management UI: http://localhost:15672

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🧪 Example API Request (User Service)

POST http://localhost:3000/users
Content-Type: application/json

{
  "name": "Andrii"
}

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📡 How It Works

1. The User Service performs user actions (e.g., registration).
2. It publishes a notification event with type and payload to RabbitMQ.
3. The Notification Service listens for events from RabbitMQ.
4. When an event is received:
   • It selects the right notification channel (push).
   • Uses a Message Template Resolver to create a title and body for the notification based on event type.
   • Sends the notification via the corresponding service (e.g., PushService sends an HTTP POST to the webhook URL).
5. Notifications are logged for monitoring.