goGateway

A lightweight and scalable API Gateway in Go designed for microservice architectures. It offloads critical cross-cutting concerns by providing centralized JWT authentication, distributed tier based rate limiting with Redis, and resilience through circuit breakers, all configured dynamically via Consul.

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Core Features

• Dynamic Routing: Routes are loaded from Consul in real-time. Add, remove, or modify routes with no gateway restarts (hot-reloading).
• Centralized Middleware:
  • JWT Authentication: Secure routes with JWT validation.
  • Tiered Rate Limiting: Apply flexible, per-route, per-user-tier rate limits using the Sliding Window Log algorithm with Redis.
  • Circuit Breaker: Automatically detects failing downstream services and opens the circuit to prevent cascading failures.
• Scalable Architecture: Built on a stateless model for easy horizontal scaling.
• Observability: Structured JSON logging for easy parsing and analysis.
• Containerized: The entire environment (gateway, services, Consul, Redis) is managed via Docker Compose for easy, one-command setup.

Architecture Diagram

Getting Started

Prerequisites

• Go (version 1.23+)
• Docker and Docker Compose

Running the Project

1. Clone the repository:

   git clone https://github.com/sahasourav17/goGateway.git
   cd goGateway

2. Build and run the entire environment: This single command starts the gateway, two mock services, Consul, and Redis.

   docker-compose up --build

   (You can add the -d flag to run it in the background)

3. Load the initial configuration into Consul: In a new terminal window, run this command to upload the routing rules. The gateway will detect this and configure itself automatically.

   docker exec -i consul consul kv put gateway/config - < ./config/config.json

4. Access the Consul UI: You can view the configuration and service health in your browser at http://localhost:8500.

API Testing & Endpoints

Generating a Test JWT

To access protected routes, you need a valid JWT.

1. Go to jwt.io.
2. Set the algorithm to HS256.
3. Set the secret key to fast-secure-scalable-api-gw-built-from-scratch or you can change it to whatever you want
4. Use one of the following payloads:
   • Default User: {"user_id": "user-default-123"}
   • Premium User: {"user_id": "user-premium-456", "tier": "premium"}
5. Copy the generated token to use in the examples below.

Example curl Commands

• Test a Public Route (Rate Limit: 5 req/min)

  curl -i http://localhost:8080/public/users/health

• Test a Protected Route (No Token - Should Fail)

  curl -i http://localhost:8080/api/users/profile
  # Expected: HTTP/1.1 401 Unauthorized

• Test a Protected Route (With Token) Replace YOUR_JWT with a token you generated.

  curl -i -H "Authorization: Bearer YOUR_JWT" http://localhost:8080/api/users/profile
  # Expected: HTTP/1.1 200 OK
  # Check the response headers for RateLimit-* details!

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