🛍️ Spring Boot Microservices E-Commerce Platform

This project is a modular, production-grade E-Commerce backend system built using Spring Boot microservices architecture. It supports secure user management, real-time inventory/order updates, asynchronous communication, and seamless third-party integrations.

🔧 Tech Stack

• Backend Framework: Spring Boot
• Microservices: Product, Order, Inventory, Notification
• API Gateway: Custom Spring Cloud Gateway
• Authentication & Authorization: Keycloak (via Docker Compose)
• Databases:
  • PostgreSQL (hosted on NeonDB)
• Message Broker: Apache Kafka (via Confluent Cloud)
• Communication:
  • REST (synchronous)
  • Kafka (asynchronous)
• Containerization: Docker (each service has its own Dockerfile)
• Deployment Target: Google Cloud Platform (Compute Engine, 2 VMs)
• Monitoring: Planned
• Circuit Breaker: Planned via Resilience4j

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🧩 Microservices Overview

📦 Product Service

• CRUD for product catalog
• REST APIs
• PostgreSQL integration

🛒 Order Service

• Manages order placement and tracking
• Sends Kafka events to Notification service
• Uses PostgreSQL (via NeonDB)

📦 Inventory Service

• Manages product inventory levels
• Consumes order events
• Decreases stock, updates product availability
• Uses PostgreSQL (via NeonDB)

🔔 Notification Service

• Listens to order events via Kafka
• Sends email/SMS notifications (placeholder logic)
• Stateless service

🌐 API Gateway

• Acts as a unified entry point for external clients
• Handles routing and forwarding
• Integrated with Keycloak for secured endpoints

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🛡️ Security

• Keycloak manages user registration, login, and RBAC (Role-Based Access Control).
• Keycloak is containerized and run locally using Docker Compose.

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📦 Dockerization

Each service includes its own Dockerfile:

• Simple multi-stage builds
• Environment-specific variables injected at runtime
• Compatible with local Docker Desktop and cloud deployment

✅ Note: Database services are not containerized. PostgreSQL is hosted on NeonDB.

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☁️ Deployment Plan

✅ Local Development

• Run all services using Docker Desktop
• Kafka handled via Confluent Cloud (no local Kafka setup needed)
• NeonDB used for PostgreSQL access

☁️ Cloud Deployment (GCP)

• 2 VMs on Google Compute Engine
• Docker images pulled or built directly on VMs
• LoadBalancer service for API Gateway
• Free-tier compliant setup

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⚙️ Kafka Topics & Flow

1. order-events

   • Published by Order Service
   • Consumed by Inventory Service & Notification Service

2. inventory-updates (Optional)

   • Published by Inventory after stock update

Kafka is fully managed via Confluent Cloud, reducing ops overhead.

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🔐 Environment Config

Use .env files or secure secrets management to inject:

# NeonDB URLs
ORDER_DB_URL=jdbc:postgresql://<order-neon-url>
INVENTORY_DB_URL=jdbc:postgresql://<inventory-neon-url>

# Kafka
KAFKA_BOOTSTRAP_SERVERS=<confluent-cloud-bootstrap>
KAFKA_API_KEY=...
KAFKA_API_SECRET=...

# Keycloak
KEYCLOAK_AUTH_URL=http://localhost:8085/realms/<realm>