Go 如何基于IP限制HTTP访问频率的方法实现

package main

import (
 "log"
 "net/http"
)

func main() {
 mux := http.NewServeMux()
 mux.HandleFunc("/", okHandler)

 if err := http.ListenAndServe(":8888", mux); err != nil {
  log.Fatalf("unable to start server: %s", err.Error())
 }
}

func okHandler(w http.ResponseWriter, r *http.Request) {
 // 某些消耗很高的数据库请求
 w.Write([]byte("alles gut"))
}

package main

import (
 "sync"

 "golang.org/x/time/rate"
)

// IPRateLimiter .
type IPRateLimiter struct {
 ips map[string]*rate.Limiter
 mu *sync.RWMutex
 r rate.Limit
 b int
}

// NewIPRateLimiter .
func NewIPRateLimiter(r rate.Limit, b int) *IPRateLimiter {
 i := &IPRateLimiter{
  ips: make(map[string]*rate.Limiter),
  mu: &sync.RWMutex{},
  r: r,
  b: b,
 }

 return i
}

// AddIP 创建了一个新的速率限制器，并将其添加到 ips 映射中,
// 使用 IP地址作为密钥
func (i *IPRateLimiter) AddIP(ip string) *rate.Limiter {
 i.mu.Lock()
 defer i.mu.Unlock()

 limiter := rate.NewLimiter(i.r, i.b)

 i.ips[ip] = limiter

 return limiter
}

// GetLimiter 返回所提供的IP地址的速率限制器(如果存在的话).
// 否则调用 AddIP 将 IP 地址添加到映射中
func (i *IPRateLimiter) GetLimiter(ip string) *rate.Limiter {
 i.mu.Lock()
 limiter, exists := i.ips[ip]

 if !exists {
  i.mu.Unlock()
  return i.AddIP(ip)
 }

 i.mu.Unlock()

 return limiter
}

package main

import (
 "log"
 "net/http"
)

var limiter = NewIPRateLimiter(1, 5)

func main() {
 mux := http.NewServeMux()
 mux.HandleFunc("/", okHandler)

 if err := http.ListenAndServe(":8888", limitMiddleware(mux)); err != nil {
  log.Fatalf("unable to start server: %s", err.Error())
 }
}

func limitMiddleware(next http.Handler) http.Handler {
 return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  limiter := limiter.GetLimiter(r.RemoteAddr)
  if !limiter.Allow() {
   http.Error(w, http.StatusText(http.StatusTooManyRequests), http.StatusTooManyRequests)
   return
  }

  next.ServeHTTP(w, r)
 })
}

func okHandler(w http.ResponseWriter, r *http.Request) {
 // 非常重要的数据请求（译者注：这句话没理解到位）
 w.Write([]byte("alles gut"))
}

go get golang.org/x/time/rate
go build -o server .
./server

brew install vegeta

GET http://localhost:8888/

vegeta attack -duration=10s -rate=100 -targets=vegeta.conf | vegeta report