# Goroutine 实现 Ping Pong

Posted by FutureTechx on April 1, 2021

# 每日一练：

## 实现两个Goroutine通信，要求如下：

• （a）实现ping-pong效果
• （b）在第三个Goroutine中查找前两个Goroutine各自发送了多少消息，并可随时设置各自ping-pong的频率
• （c）保证程序能任意长时间运行，且收到ctrl+c信号后，全身而退（即保证各个Goroutine完整退出）
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package main

import (
"fmt"
"os"
"time"
"context"
"log"
"os/signal"
)

// The pinger prints a ping and waits for a pong
func pinger(ctx context.Context, pinger chan int, ponger chan int) {

<-ctx.Done()
log.Println("exit pinger")
_, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()

for {
<-pinger
fmt.Println("ping")
time.Sleep(500 * time.Millisecond)
ponger <-  1
}
}

// The ponger prints a pong and waits for a ping
func ponger(ctx context.Context, pinger chan int, ponger chan int) {

<-ctx.Done()
log.Println("exit ponger")
_, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()

for {

<-ponger
fmt.Println("pong")
time.Sleep(200 * time.Millisecond)
pinger <- 1
}
}

func contalSendRateLimit(){

}

var ctx, cancelFunc = context.WithCancel(context.Background())

func SetupCloseHandler() {
//register Interrupt signal
signalChan := make(chan os.Signal, 1)
signal.Notify(signalChan, os.Interrupt)
go func() {
signal := <-signalChan
cancelFunc()
// os.Exit(0)
}()
}

func main() {

// wg := sync.WaitGroup{}
SetupCloseHandler()
ping := make(chan int)
pong := make(chan int)

go pinger(ctx,ping, pong)
go ponger(ctx,ping, pong)

// The main goroutine starts the ping/ping by sending into the ping channel
ping <- 1
for {
time.Sleep(5 * time.Second)
}
// os.Exit(0)
}