net/http request rate limiter based on the Sliding Window Counter pattern inspired by CloudFlare https://blog.cloudflare.com/counting-things-a-lot-of-different-things/.
The sliding window counter pattern is accurate, smooths traffic and offers a simple counter design to share a rate-limit amoung a cluster of servers. For example, if you'd like to use redis to coordinate a rate-limit across a group of microservices you just need to implement the httprate.LimitCounter interface to support an atomic increment and get.
package main
import (
"net/http"
"github.com/go-chi/chi"
"github.com/go-chi/chi/middleware"
"github.com/go-chi/httprate"
)
func main() {
r := chi.NewRouter()
r.Use(middleware.Logger)
// Enable httprate request limiter of 100 requests per minute.
//
// In the code example below, rate-limiting is bound to the request IP address
// via the LimitByIP middleware handler.
//
// To have a single rate-limiter for all requests, use httprate.LimitAll(..).
//
// Please see _example/main.go for other more, or read the library code.
r.Use(httprate.LimitByIP(100, 1*time.Minute))
r.Get("/", func(w http.ResponseWriter, r *http.Request) {
w.Write([]byte("."))
})
http.ListenAndServe(":3333", r)
}MIT