Distributed Rate Limiter

A distributed rate limiter service built with Go, featuring Redis-backed storage and load balancing capabilities. The service also includes monitoring with Prometheus and Grafana.

Features

• Redis-backed sliding window rate limiting algorithm
• Distributed architecture with load balancing
• Prometheus metrics and Grafana dashboards
• Docker containerization
• Comprehensive test suite (unit, integration, and load tests)
• Configurable rate limits and time windows
• Health checks and automatic backend failover

Architecture

The system consists of several components:

• Rate Limiter Service: Implements the core rate limiting logic using a sliding window algorithm
• Load Balancer: Distributes traffic across multiple rate limiter instances
• Redis: Stores rate limiting data and enables distributed coordination
• Prometheus: Collects and stores metrics
• Grafana: Visualizes metrics and provides monitoring dashboards

Prerequisites

• Docker and Docker Compose
• Go 1.22 or later (for local development)
• Redis (automatically handled by Docker Compose)

Quick Start

1. Clone the repository:

   git clone https://github.com/stemitom/rate-limiter.git
   cd rate-limiter

2. Start the services:

   ./run.sh

This will start:

• Two rate limiter instances (::8081, ::8082)
• Load balancer (::8080)
• Redis (::6379)
• Prometheus (::9090)
• Grafana (::3000)

Configuration

The following environment variables can be configured:

Rate Limiter Service

• PORT: Service port (default: 8081)
• REDIS_ADDR: Redis address (default: localhost:6379)
• RATE_LIMIT: Requests per window (default: 10)
• WINDOW_SIZE: Time window duration (default: 1s)

Load Balancer

• BACKEND_1_URL: First backend URL
• BACKEND_2_URL: Second backend URL
• BACKEND_1_WEIGHT: Traffic weight for first backend
• BACKEND_2_WEIGHT: Traffic weight for second backend

Testing

Run the test suite:

./scripts/test.sh

This will execute:

• Unit tests
• Integration tests
• Load tests

Load Testing

The project includes a load testing tool that can be used to benchmark the rate limiter:

go run cmd/loadtest/main.go -rps 100 -duration 10s -url http://localhost:8080

Parameters:

• -rps: Requests per second
• -duration: Test duration
• -url: Target URL

Monitoring

• Grafana Dashboard: http://localhost:3000 (default credentials: admin/admin)
• Prometheus: http://localhost:9090
• Metrics endpoints:
  • Rate Limiter: http://localhost:8081/metrics
  • Load Balancer: http://localhost:8080/metrics

API Endpoints

• GET /: Main endpoint for rate-limited requests
• GET /health: Health check endpoint
• GET /metrics: Prometheus metrics endpoint

License

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