Go Rate Limiter

This is my own implementation of an API rate-limiter middleware in Go using different algorithms. Coding Challenges series by John Crickett https://codingchallenges.fyi/challenges/challenge-rate-limiter/

• Token Bucket
• Fixed Window
• Sliding Window Log
• Sliding Window Counter
• Sliding Window Counter across multiple servers using Redis

Requirements

• Install GO v1.21
• Install Make Windows | [Mac] brew install make

Setup

make build

make install

Run

go-rate-limiter <algorithm> --flag1 --flag2

Tests

make test

Stress Tests

I am using the loadtest package to run stress tests against the API server directly from the CLI. This can also be achieved by installing Postman or .

1. Install loadtest package using NPM

npm install -g loadtest

2. Run the server

go-rate-limiter tokenBucket --capacity 20 --refillRate 1

3. Run the tests

loadtest -c <number of concurrent users> --cores <number of cpu cores> --rps <target request per second by client> -k -n <number of requests to perform> http://localhost:8080/limited

Docker

You can run Redis together with multiple instances of the app to test the Sliding Window Counter algorithm across multiple servers:

make run-docker

• API Servers will be running on port 8085 and 8086.

Packages

1. Gin: Fast Web/API web server

2. Cobra: CLI: Used to create CLI commands

3. Go-redis/v9: Read/write data to Redis

4. Testify: Testing utilities, easy assertions, mocking, etc