Rate Limiter in Node.js

A simple rate limiter in Node.js, using Redis for rate limiting and queueing, with two rate limiters (1 request per second, 20 requests per minute). No requests are dropped.

Prerequisites

Make sure you have the following installed:

• Node.js (v12 or higher)
• Redis (either locally or in the cloud)

Installation

1. Clone the repository:

   git clone https://github.com/bitorsic/nodejs-rate-limiting.git
   cd nodejs-rate-limiting

2. Install the dependencies:

   npm install

3. Set up Redis:

   • If you don't have Redis installed locally, you can follow the instructions here for installation.
   • Alternatively, you can set up a cloud instance of Redis using services like Redis Labs or AWS ElastiCache.

4. Configure environment variables:

   • Copy the .env.example file to .env and update the values as needed:

   cp .env.example .env

Usage

To start the application, run:

node index.js

Make sure the Redis instance is running and correctly configured.

Hit the endpoint using cURL:

curl -X POST http://localhost:3000/api/v1/task -H "Content-Type: application/json" -d '{"user_id": 123}'

(Change the user_id to test the rate limiting)

The logs should be saved to the file /logs/task.log

Rate Limiters

This project implements the following rate limiters:

• 1 request per second
• 20 requests per minute

No requests are dropped; they are queued and processed accordingly.

Explanation

The directory tree with explanation is as follows (including only the necessary files):

.
├── controllers/
│   └── v1/
│       └── taskController.js - adding the task to queue upon hitting api
├── queues/
│   └── taskQueues.js - maintaining the queue for tasks for each user
├── routes/
│   └── v1/
│       └── task.js - mounting the taskController to /api/v1/task
├── utils/
│   ├── logger.js - logging to the /logs/ directory
│   ├── rateLimiter.js - logic for rate limiting
│   └── redis.js - exporting redis client for use by other modules
├── workers/
│   └── taskWorker.js - logic for executing tasks in queue
├── .env - environment variables for port and redis config
├── app.js - code run by each cluster node
├── config.js - default config for redis to be used by IORedis package
└── index.js - entry point, creating cluster and nodes