Go Rate Limiter

Token bucket rate limiter for Go with per-client (IP/UserID) support.

Installation

go get github.com/Prasanth-S7/rate-limiter@v1.0.0

Example

package main

import (
	"net/http"
	"time"

	ratelimiter "github.com/Prasanth-S7/rate-limiter"
	"github.com/Prasanth-S7/rate-limiter/middleware"
)

func main() {
	manager := ratelimiter.NewManager(10, 2, 10*time.Minute)
	limiter := middleware.New(manager, false)

	// Use the limiter in your application, for example, as an HTTP middleware
	http.Handle("/api", limiter.Handler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("Hello, World!"))
	})))

	http.ListenAndServe(":8080", nil)
}

Manager Configuration

NewManager(capacity, fillRate, ttl) creates a rate limiter manager with three parameters:

Parameter	Type	Description
capacity	int	Maximum tokens a client can accumulate. This is the burst capacity - how many requests a client can make in a short spike before being limited.
fillRate	float64	Tokens added per second. The steady-state rate limit. A value of 2 means 2 tokens (requests) are added every second.
ttl	time.Duration	Time-to-live for inactive client buckets. If a client hasn't made a request in this duration, their bucket is deleted to free memory.