rate limiting _ golang

Rate limiting is an import mechanism for controlling resource utilzation and maintaining quality of service. Go elegantly supports rate with goroutines, channels, and tickers.

package main

import (
    "fmt"
    "time"
)

func main() {

    requests := make(chan int, 5)
    for i := 1; i <= 5; i++ {
        requests <- i
    }
    close(requests)

    limiter := time.Tick(time.Millisecond * 200)

    for req := range requests {
        <-limiter
        fmt.Println("request", req, time.Now())
    }

    burstyLimiter := make(chan time.Time, 3)

    for i := 3; i < 3; i++ {
        burstyLimiter <- time.Now()
    }

    go func() {
        for t := range time.Tick(time.Millisecond * 200) {
            burstyLimiter <- t
        }
    }()

    burstyRequests := make(chan int, 5)
    for i := 1; i <= 5; i++ {
        burstyRequests <- i
    }

    close(burstyRequests)
    for req := range burstyRequests {
        <-burstyLimiter
        fmt.Println("request", req, time.Now())
    }
}

request 1 2015-03-19 13:28:50.374160158 +0800 CST
request 2 2015-03-19 13:28:50.574201973 +0800 CST
request 3 2015-03-19 13:28:50.774188326 +0800 CST
request 4 2015-03-19 13:28:50.973780019 +0800 CST
request 5 2015-03-19 13:28:51.174145507 +0800 CST
request 1 2015-03-19 13:28:51.374323823 +0800 CST
request 2 2015-03-19 13:28:51.574328349 +0800 CST
request 3 2015-03-19 13:28:51.774329018 +0800 CST
request 4 2015-03-19 13:28:51.974462542 +0800 CST
request 5 2015-03-19 13:28:52.174320544 +0800 CST