garethpaul/go-ratelimiter

A golang rate limiter.

Limiter

This is a generic middleware to rate-limit HTTP requests

Tutorial

package main

import (
    "github.com/garethpaul/go-ratelimiter"
    "net/http"
    "time"
)

func HelloHandler(w http.ResponseWriter, req *http.Request) {
    w.Write([]byte("Hello, World!"))
}

func main() {
    // Create a request limiter per handler.
    http.Handle("/", limiter.LimitFuncHandler(limiter.NewLimiter(1, time.Second), HelloHandler))
    http.ListenAndServe(":12345", nil)
}

Features

1. Rate-limit by request's remote IP, path, methods, custom headers, & basic auth usernames.

   l := limiter.NewLimiter(1, time.Second)
   
   // Configure list of places to look for IP address.
   // By default it's: "RemoteAddr", "X-Forwarded-For", "X-Real-IP"
   // If your application is behind a proxy, set "X-Forwarded-For" first.
   l.IPLookups = []string{"RemoteAddr", "X-Forwarded-For", "X-Real-IP"}
   
   // Limit only GET and POST requests.
   l.Methods = []string{"GET", "POST"}
   
   // Limit request headers containing certain values.
   // Typically, you prefetched these values from the database.
   l.Headers = make(map[string][]string)
   l.Headers["X-Access-Token"] = []string{"abc", "123"}
   
   // Limit based on basic auth usernames.
   // Typically, you prefetched these values from the database.
   l.BasicAuthUsers = []string{"gareth", "matthew", "ryan"}
   

2. Each request handler can be rate-limited individually.

3. Compose your own middleware by using LimitByKeys().

4. Limiter does not require external storage since it uses an algorithm called Token Bucket (Go library: golang.org/x/time/rate).