golang for-select 优雅的退出

• 启动两个做为生产者的go-routing,
• 分别将数据生产的数据写入两个带缓冲的通道cha1,ch2
• 分别模拟在Main go-routing和 sub go-routing中通过for-select循环读取两个通道的值并打印
• 通过3种方式优雅的退出main go-routing

exit for-select in go-routing

https://play.golang.org/p/Ar4389-87QE

package main

import (
   // "time"
    "fmt"
)

func produce(id int, ch chan string, quitSub chan int){
        for i:=0;i< 10;i++{
        ch <- fmt.Sprintf("msg:%d:%d",id,i)
        }
        quitSub <- id
}

func main() {
    c1 := make(chan string, 1)                 //定义两个有缓冲的通道，容量为1
    c2 := make(chan string, 1)
    quitForSelect := make(chan int, 2)    //用于通知退出for select循环
    quitTag := []int{}                                  //用于读取和存储quitForSlect通道的两个值，保证两个product都写入完毕

    quitMain := make(chan bool)            //阻塞main gorouting,等待for select 处理完成

    go produce(1, c1, quitForSelect)
    go produce(2, c2, quitForSelect)

     go func(){
        for   {                //使用select来等待这两个通道的值，然后输出
            select {
            case msg1 := <- c1:
                    fmt.Println(msg1)
            case msg2 := <- c2:
                    fmt.Println(msg2)
            case q := <- quitForSelect:  
                fmt.Println("got quit tag for Gorouting id:", q)
                quitTag = append(quitTag,q)
                if len(quitTag) == 2{
                        fmt.Println("end to quit Main ")
                    quitMain <- true
                }
            }
        }
    }()

   <-quitMain
   fmt.Println("exit from main")
}

exit for-select by "break" in Main go-routing

https://play.golang.org/p/vEUvAslRqVw

package main

import (
    "fmt"
)

func produce(id int, ch chan string, quitSub chan int) {
    for i := 0; i < 10; i++ {
        ch <- fmt.Sprintf("msg:%d:%d", id, i)
    }
    quitSub <- id
}

func main() {
    c1 := make(chan string, 1) //定义两个有缓冲的通道，容量为1
    c2 := make(chan string, 1)
    quitForSelect := make(chan int, 2) //用于通知退出for select循环
    quitTag := []int{}                 //用于读取和存储quitForSlect通道的两个值，保证两个product都写入完毕

    go produce(1, c1, quitForSelect)
    go produce(2, c2, quitForSelect)

ForEnd:
    for { //使用select来等待这两个通道的值，然后输出
        select {
        case msg1 := <-c1:
            fmt.Println(msg1)
        case msg2 := <-c2:
            fmt.Println(msg2)
        case q := <-quitForSelect:
            fmt.Println("got quit tag for Gorouting id:", q)
            quitTag = append(quitTag, q)
            if len(quitTag) == 2 {
                fmt.Println("end to quit Main ")
                break ForEnd
            }
        }
    }

    fmt.Println("exit from main")
}

exit for-select by "goto" in Main go-routing

https://play.golang.org/p/GKD_NYpoMdT

package main

import (
    "fmt"
)

func produce(id int, ch chan string, quitSub chan int) {
    for i := 0; i < 10; i++ {
        ch <- fmt.Sprintf("msg:%d:%d", id, i)
    }
    quitSub <- id
}

func main() {
    c1 := make(chan string, 1) //定义两个有缓冲的通道，容量为1
    c2 := make(chan string, 1)
    quitForSelect := make(chan int, 2) //用于通知退出for select循环
    quitTag := []int{}                 //用于读取和存储quitForSlect通道的两个值，保证两个product都写入完毕

    go produce(1, c1, quitForSelect)
    go produce(2, c2, quitForSelect)

    for { //使用select来等待这两个通道的值，然后输出
        select {
        case msg1 := <-c1:
            fmt.Println(msg1)
        case msg2 := <-c2:
            fmt.Println(msg2)
        case q := <-quitForSelect:
            fmt.Println("got quit tag for Gorouting id:", q)
            quitTag = append(quitTag, q)
            if len(quitTag) == 2 {
                fmt.Println("end to quit Main ")
                goto ForEnd
            }
        }
    }
ForEnd:
    fmt.Println("go to here from for-select")

    fmt.Println("exit from main")
}