Testing out rate limiting

ratelimit.go

package main

import (
	"fmt"
	"math/rand"
	"sync"
	"time"

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

func main() {

	rand.Seed(time.Now().UnixNano())
	
	// Allow at most 50 (burst) per second
	// Refresh tokens at 100 per second (or in other words every 10ms)
	l := rate.NewLimiter(100, 50)

	st := time.Now()
	var wg sync.WaitGroup
	for i := 0; i < 3000; i++ {
		wg.Add(1)
		go func(i int) {
			for {
				if l.Allow() {
					fmt.Printf("[%d] allowed in %v\n", i, time.Now().Sub(st))
					break
				} else {
					fmt.Printf("[%d] !!disallowed in %v\n", i, time.Now().Sub(st))
					time.Sleep(2*time.Second + time.Duration(rand.Intn(10000*i)))
				}
			}
			wg.Done()
		}(i)
	}

	wg.Wait()
}