WORK IN PROGRESS

E-Commerce Microservices Platform

A production-grade, distributed e-commerce backend system built with Go, gRPC, Kafka, GraphQL, and Kubernetes.

🚀 Overview

This project demonstrates a complete microservices architecture for an e-commerce platform, featuring:

• Microservices Architecture: 5 independently deployable services
• Event-Driven Design: Asynchronous communication via Kafka
• API Gateway: Unified GraphQL interface
• Authentication: JWT-based auth with role-based access control
• Caching: Redis for performance optimization
• Observability: Prometheus + Grafana monitoring, ELK logging
• Container Orchestration: Docker Compose + Kubernetes
• CI/CD: Automated testing and deployment pipelines

📐 Architecture

┌─────────────────────────────────────────────────────────────┐
│                    GraphQL Gateway                          │
│              (Unified API + Authentication)                 │
└──────────────────┬──────────────────────────────────────────┘
                   │ gRPC
        ┌──────────┼──────────┬──────────┬──────────┐
        │          │          │          │          │
   ┌────▼───┐ ┌───▼────┐ ┌───▼────┐ ┌───▼─────┐ ┌──▼─────────┐
   │Account │ │Catalog │ │ Order  │ │Payment  │ │Notification│
   │Service │ │Service │ │Service │ │Service  │ │  Service   │
   └────┬───┘ └───┬────┘ └───┬────┘ └───┬─────┘ └──┬─────────┘
        │         │          │          │          │
        └─────────┴──────────┴──────────┴──────────┘
                          │
                     Kafka Event Bus
                          │
        ┌─────────────────┼─────────────────┐
        │                 │                 │
   PostgreSQL          Redis          Elasticsearch

🎯 Services

1. Account Service

• User registration and authentication
• JWT token generation and validation
• Role-based access control (USER/ADMIN)
• Password hashing with bcrypt

Tech Stack: Go, gRPC, PostgreSQL, JWT

2. Catalog Service

• Product CRUD operations
• Full-text search with Elasticsearch
• Redis caching for performance
• Inventory management

Tech Stack: Go, gRPC, Elasticsearch, Redis

3. Order Service

• Order creation and management
• Order status tracking
• Integration with Account & Catalog services
• Event publishing to Kafka

Tech Stack: Go, gRPC, PostgreSQL, Kafka

4. Payment Service

• Payment processing (Stripe mock integration)
• Idempotency key support
• Transaction management
• Event-driven status updates

Tech Stack: Go, gRPC, PostgreSQL, Kafka, Redis

5. Notification Service

• Email notifications (SMTP mock)
• Event-driven notifications
• Template-based messaging
• Notification history

Tech Stack: Go, Kafka

6. GraphQL Gateway

• Unified API for all services
• Authentication middleware
• Rate limiting
• Query complexity analysis

Tech Stack: Go, gqlgen, gRPC clients

🛠️ Tech Stack

Languages & Frameworks:

• Go 1.21+
• gRPC & Protocol Buffers
• GraphQL (gqlgen)

Databases:

• PostgreSQL 15
• Elasticsearch 8
• Redis 7

Message Queue:

• Apache Kafka

Observability:

• Prometheus (metrics)
• Grafana (dashboards)
• ELK Stack (logging)

DevOps:

• Docker & Docker Compose
• Kubernetes
• GitHub Actions (CI/CD)

Testing:

• Go testing framework
• Testcontainers (integration tests)
• k6 (load testing)

🚦 Getting Started

Prerequisites

• Go 1.21 or higher
• Docker & Docker Compose
• Protocol Buffers compiler (protoc)
• kubectl (for Kubernetes deployment)

Installation

1. Clone the repository

git clone https://github.com/Ujjwaljain16/E-commerce-Backend.git
cd E-commerce-Backend

2. Install dependencies

go mod download

3. Generate Protocol Buffer code

make proto-gen

4. Start infrastructure services

docker-compose up -d

5. Run database migrations

make migrate-up

6. Start all services

# Terminal 1: Account Service
cd account/cmd/account && go run main.go

# Terminal 2: Catalog Service
cd catalog/cmd/catalog && go run main.go

# Terminal 3: Order Service
cd order/cmd/order && go run main.go

# Terminal 4: Payment Service
cd payment/cmd/payment && go run main.go

# Terminal 5: Notification Service
cd notification/cmd/notification && go run main.go

# Terminal 6: GraphQL Gateway
cd graphql && go run main.go

7. Access the GraphQL Playground

http://localhost:8000/playground

📊 Example GraphQL Queries

Register User

mutation {
  register(input: {
    name: "John Doe"
    email: "john@example.com"
    password: "SecurePass123!"
  }) {
    account {
      id
      name
      email
    }
    accessToken
  }
}

Create Product

mutation {
  createProduct(input: {
    name: "Laptop"
    description: "High-performance laptop"
    price: 999.99
  }) {
    id
    name
    price
  }
}

Create Order

mutation {
  createOrder(input: {
    accountId: "acc_123"
    products: [
      { id: "prod_456", quantity: 2 }
    ]
  }) {
    id
    totalPrice
    status
  }
}

🧪 Testing

Run unit tests

make test

Run integration tests

make integration-test

Run with coverage

make coverage

Load testing

make load-test

📈 Monitoring

Prometheus Metrics

• URL: http://localhost:9090
• Service-level metrics (RED: Rate, Errors, Duration)
• Business metrics (orders/sec, revenue)

Grafana Dashboards

• URL: http://localhost:3000
• Credentials: admin/admin
• Pre-configured dashboards for all services

Logs (Kibana)

• URL: http://localhost:5601
• Centralized logging with correlation IDs

🚀 Deployment

Docker Compose (Local Development)

docker-compose up --build

Kubernetes (Production)

# Deploy to Kubernetes
kubectl apply -f k8s/

# Check deployment status
kubectl get pods -n ecommerce

# Access services
kubectl port-forward svc/graphql-gateway 8000:8080

📂 Project Structure

ecommerce-microservices/
├── account/              # Account service
│   ├── pb/              # Generated protobuf code
│   ├── cmd/account/     # Service entrypoint
│   ├── migrations/      # Database migrations
│   └── *.go             # Service implementation
├── catalog/             # Catalog service
├── order/               # Order service
├── payment/             # Payment service
├── notification/        # Notification service
├── graphql/             # GraphQL gateway
├── pkg/                 # Shared packages
│   ├── auth/           # JWT utilities
│   ├── kafka/          # Kafka producer/consumer
│   ├── cache/          # Redis client
│   ├── logger/         # Structured logging
│   └── metrics/        # Prometheus metrics
├── k8s/                 # Kubernetes manifests
├── monitoring/          # Prometheus, Grafana configs
├── tests/               # Integration & load tests
├── docker-compose.yaml
└── Makefile

🤝 Contributing

Contributions are welcome! Please read CONTRIBUTING.md for details on our code of conduct and the process for submitting pull requests.

📝 License

This project is licensed under the MIT License - see the LICENSE file for details.

👨‍💻 Author

Ujjwal Jain

• GitHub: @Ujjwaljain16
• LinkedIn: Ujjwal Jain

🙏 Acknowledgments

• Inspired by microservices architectures at Amazon, Netflix, and Uber
• Built as a learning project to demonstrate production-grade backend engineering

📊 Performance Benchmarks

• Order Creation: 800+ req/sec
• Product Search: 1200+ req/sec
• Authentication: 500+ req/sec
• P95 Latency: < 100ms for all endpoints

🔒 Security

• JWT-based authentication
• Password hashing with bcrypt
• Input validation on all endpoints
• SQL injection prevention
• Rate limiting
• CORS configuration

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