Distributed Rate Limiter Demo

Overview

This project is a Spring Boot service that demonstrates a Redis-backed, fixed-window rate limiter. Every request is checked against a per-client counter stored in Redis and returns an X-RateLimit-Remaining header. When the limit is exceeded, the service responds with HTTP 429.

Requirements

• JDK 17 (for local builds)
• Redis (local or via Docker)
• Docker + Docker Compose (for containerized runs)

Install / Build

Build the application JAR with the Maven wrapper:

./mvnw clean package

Run Locally

Start Redis (example using Docker):

docker run --rm -p 6379:6379 redis

Run the app:

./mvnw spring-boot:run

The app listens on http://localhost:8080.

Run with Docker

The Docker image expects the JAR to exist under target/.

./mvnw clean package
docker compose up --build

Endpoints

• GET /health returns OK and is publicly accessible.
• All requests include X-RateLimit-Remaining and are rate-limited.
• Non-/health endpoints require HTTP Basic auth (Spring Security defaults). Check the app logs for the generated password or configure your own credentials.

Configuration

Rate limit defaults are in src/main/resources/application.properties:

ratelimit.limit=5
ratelimit.windowSeconds=60

Redis connection defaults to the redis hostname for Docker Compose.