🚀 Token Management Service

📖 Overview

This is a scalable Token Management Service built with NestJS and Redis, designed to efficiently generate, assign, unblock, and manage unique tokens with auto-expiry mechanisms.

🎯 Key Features

✅ Assigns unique tokens dynamically with O(1) operations
✅ Supports multi-instance deployments using Redis Atomic Operations
✅ Ensures scalability and consistency across multiple application pods
✅ Deployable in Docker & Kubernetes environments

---

🛠️ Tech Stack

Component	Technology
Backend	NestJS (TypeScript)
Database	Redis (Atomic Operations, Pub/Sub)
Containerization	Docker & Kubernetes
Monitoring	Prometheus & Grafana
Load Balancer	NGINX / Kubernetes Service

---

🏗️ System Architecture

        ┌─────────────────────────────────────┐
        │          API Gateway (NestJS)       │
        ├─────────────────────────────────────┤
        │         Token Service (NestJS)      │
        │     ┌─────────────────────────┐     │
        │     │     Redis Database      │     │
        │     │  - Token Storage        │     │
        │     │  - Auto-Expiry Handling │     │
        │     └─────────────────────────┘     │
        ├─────────────────────────────────────┤
        │     **Design Patterns Used:**       │
        │ - Factory Pattern (Token Service)   │
        │ - Singleton (Logger, Config, Redis) │
        │ - Repository Pattern (Redis Access) │
        └─────────────────────────────────────┘

---

📖 Key Design Decisions

✅ Redis Sorted Sets (ZSET) for Token Storage → Allows O(log N) insertions & retrievals. ✅ Factory Pattern for Token Service → Standardized token creation & assignment. ✅ Singleton Pattern for Logger, Config, and Redis Connection → Ensures a single instance across the application. ✅ Repository Pattern for Redis Interactions → Abstracts direct Redis operations from business logic. ✅ Auto-Cleanup Jobs → Keeps the token pool optimized without manual intervention. ✅ Microservice Architecture → Supports horizontal scaling with multiple API instances.

---

💭 Logical Flow

---

🚀 Setup & Installation

1️⃣ Clone the Repository

git clone https://github.com/luharinos/token-management-service.git
cd token-management-service

2️⃣ Install Dependencies

yarn install

3️⃣ Set Up Environment Variables

Create a .env file in the root directory:

REDIS_URL=redis://localhost:6379
TOKEN_LIFETIME=60  # Token auto-expiry in seconds
KEEP_ALIVE_LIMIT=300  # Keep-alive timeout in seconds
MAX_TOKENS=10000  # Maximum tokens allowed in the pool
TOKEN_UNBLOCK_LIFETIME=120  # Token unblock lifetime in seconds
LOG_LEVEL=INFO

4️⃣ Start Redis Locally

Ensure Redis is running locally:

brew services start redis

5️⃣ Run the Application

yarn start:dev

---

🔥 API Endpoints

1️⃣ Generate Tokens

POST /tokens/generate

Request Body:

{
  "count": 10
}

Response:

{
  "tokens": ["abc123", "def456"]
}

2️⃣ Assign a Token

POST /tokens/assign

Response:

{
  "token": "abc123"
}

3️⃣ Unblock a Token (Available after 2 minutes)

POST /tokens/unblock

Request Body:

{
  "token": "abc123"
}

4️⃣ Delete a Token

DELETE /tokens/delete

Request Body:

{
  "token": "abc123"
}

5️⃣ Keep Token Alive (Prevent Expiry)

POST /tokens/keep-alive

Request Body:

{
  "token": "abc123"
}

---

🎯 Scaling Strategy

✅ Redis Atomic Operations → Prevents race conditions
✅ Kubernetes Auto-Scaling → Deploys multiple instances as needed

---

🎯 Future Enhancements

✅ Implement Rate Limiting using API Gateway
✅ Support JWT Authentication for secured access
✅ Add Kafka or RabbitMQ for distributed messaging
✅ Improve monitoring using Prometheus & Grafana
✅ Configure Redis to run in cluster mode for better scalability and fault tolerance

---

🎯 Contributing

1. Fork the repository
2. Create a feature branch
3. Commit changes
4. Open a pull request

---

📄 License

This project is licensed under MIT License.