Test implement limit rate

limitrate.go

package main

import (
	"fmt"
	"log"
	"time"
)

func main() {
	interval := float64(1000) // start limit interval

	ticker := time.NewTicker(time.Duration(interval) * time.Millisecond)
	go func() {
		gas := 30.0 //total request queue
		for {
			select {
			case <-ticker.C:
				//check if gas is over.
				if gas <= 0 {
					gas = 1.0
					interval += interval // add slow to next request
					log.Println("ticker slow down to " + fmt.Sprint(interval/gas) + " ms")
				} else {
					log.Println("ticker accelerate " + fmt.Sprint(interval/gas) + " ms")
				}
				ticker = time.NewTicker(time.Duration(interval/gas) * time.Millisecond)
				gas-- //decrement gas
			}
		}
		log.Println("stopped")
	}()
	time.Sleep(40 * time.Second)
	log.Println("stopping ticker")
	ticker.Stop()
}