1.9.5 速率限制

1. 速率限制通常用来限制吞吐和确保在一段时间内的资源不使用会不会超标

2. 示例：任何1分钟内处理的请求数量不会超过100

   type Request interface {
   }
   
   func handle(r Request) {
   	fmt.Println(r.(int))
   }
   
   const RateLimitPeriod = time.Minute
   
   // RateLimit 任何一分钟内最多处理100个请求
   const RateLimit = 100
   
   // 处理多个请求的函数
   func handleRequests(requests <-chan Request) {
   	quotas := make(chan time.Time, RateLimit)
   
   	go func() {
   		tick := time.NewTicker(RateLimitPeriod / RateLimit)
   		defer tick.Stop()
   
   		for t := range tick.C {
   			select {
   			case quotas <- t:
   			default:
   
   			}
   		}
   	}()
   	for r := range requests {
   		<-quotas
   		go handle(r)
   	}
   }
   
   func main() {
   
   	requests := make(chan Request)
   	go handleRequests(requests)
   	for i := 0; ; i++ {
   		requests <- i
   	}
   
   }