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")
}

本文来自:简书

感谢作者:夜空一起砍猩猩

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