Awesome

speedbump

A Redis-backed Rate Limiter for Go

Cool stuff

• Backed by Redis, so it keeps track of requests across a cluster
• Extensible timing functions. Includes defaults for tracking requests per second, minute, and hour
• Works with IPv4, IPv6, or any other unique identifier
• Example middleware included for Gin (See: ginbump) and Negroni (See: negronibump)

Notes

• This library is fairly new and could break
• The current implementation could have key leakage/race conditions (See: http://redis.io/commands/incr#pattern-rate-limiter)

Usage

• Get a working Redis server
• Go get:

$ go get github.com/etcinit/speedbump

• Include it in your code

package main

import (
	"fmt"
	"time"

	"github.com/etcinit/speedbump"
	"gopkg.in/redis.v3"
)

func main() {
	client := redis.NewClient(&redis.Options{
		Addr:     "localhost:6379",
		Password: "",
		DB:       0,
	})
	hasher := speedbump.PerSecondHasher{}

	// Here we create a limiter that will only allow 5 requests per second
	limiter := speedbump.NewLimiter(client, hasher, 5)

	for {
		// This example has a hardcoded IP, but you would replace it with the IP
		// of a client on a real case.
		success, err := limiter.Attempt("127.0.0.1")

		if err != nil {
			panic(err)
		}

		if success {
			fmt.Println("Successful!")
		} else {
			fmt.Println("Limited! :(")
		}

		time.Sleep(time.Millisecond * time.Duration(100))
	}
}

• Output:

Successful!
Successful!
Successful!
Successful!
Successful!
Successful!
Limited! :(
Limited! :(
Limited! :(
Limited! :(
Limited! :(
Successful!
Successful!
Successful!
Successful!
Successful!
Successful!
Limited! :(
Limited! :(
Limited! :(
Limited! :(
Successful!
Successful!
...