Distributed Notification System

Microservices-based notification system with email and push notifications.

Team Members

• Member 1: Infrastructure + API Gateway (@teammate1)
• Member 2: User Service (@teammate2)
• Member 3: Email + Push Services (@teammate3)
• Member 4: Template Service + DevOps (@teammate4)

Quick Start

# 1. Start infrastructure
docker-compose up -d

# 2. Check services
docker-compose ps

# 3. Access services
# - API Gateway: http://localhost:3000
# - RabbitMQ UI: http://localhost:15672 (rabbit_user/rabbit_password)
# - PostgreSQL: localhost:5432

Architecture

• 5 Microservices (API Gateway, User, Email, Push, Template)
• PostgreSQL (3 databases)
• RabbitMQ (Message queue with DLQ)
• Redis (Cache)

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Microservice Architecture Diagram

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Data Flow for Sending a Notification

1. Client Request → API Gateway
2. Authentication → Validate JWT token
3. Validation → Check request format
4. User Lookup → Fetch user from User Service
5. Idempotency Check → Verify in Redis (prevent duplicates)
6. Queue Message → Publish to RabbitMQ
7. Status Tracking → Store in Redis
8. Response → Return 202 Accepted
9. Consumer Processing → Email/Push Service consumes message
10. Send → Deliver to recipient
11. Status Update → Mark as sent or failed

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Database Per Service Pattern

Each microservice has its own PostgreSQL database:

• user_service_db - User accounts, preferences, push tokens
• template_service_db - Email/push templates and versions
• notification_logs_db - Notification audit logs

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Prerequisites & Setup

System Requirements

# Minimum
- Docker 20.10+
- Docker Compose 2.0+
- 4GB RAM
- 10GB Disk space

# For local development
- Node.js 18+ (https://nodejs.org/)
- npm 9+
- Git

Development

See CONTRIBUTING.md for stacked PRs workflow.