go中父协程与子协程的生命周期

        首先说一下结论：当父协程是main协程时，父协程退出，父协程下的所有子协程也会跟着退出；当父协程不是main协程时，父协程退出，父协程下的所有子协程并不会跟着退出（子协程直到自己的所有逻辑执行完或者是main协程结束才结束）

       再来代码验证一下，下面是代码

package main

import (
	"log"
	"time"
)

func main(){
	defer trace("main")()
	go goroutine()
	time.Sleep(20*time.Second)
}

func goroutine(){
	defer trace("goroutine")()
	go goroutinue1()
	go goroutinue2()

}

func goroutinue1(){
	for i:=0; i<3; i++{
		log.Printf("this is goroutine1-%d",i)
		time.Sleep(2*time.Second)
	}
}

func goroutinue2(){
	for i:=0; i<3; i++{
		log.Printf("this is goroutine2-%d",i)
		time.Sleep(2*time.Second)
	}
}
//这个函数可以忽略，其作用只是辅助查看何时进入和退出某个方法
func trace(msg string) func() {
	log.Printf("enter %s", msg)
	start := time.Now()
	return func() { log.Printf("exit %s (%s)", msg, time.Since(start)) }
}

        下面是运行结果

2020/11/14 21:47:56 enter main
2020/11/14 21:47:56 enter goroutine
2020/11/14 21:47:56 this is goroutine1-0
2020/11/14 21:47:56 exit goroutine (0s)
2020/11/14 21:47:56 this is goroutine2-0
2020/11/14 21:47:58 this is goroutine1-1
2020/11/14 21:47:58 this is goroutine2-1
2020/11/14 21:48:00 this is goroutine2-2
2020/11/14 21:48:00 this is goroutine1-2
2020/11/14 21:48:16 exit main (20.0115622s)

         因此可以验证文章开头的那句结论，因此在项目中也要格外注意父子协程的退出关系，以免造成出现大量的孤儿协程（可以用select结合context优雅的退出协程，具体写法网友已经总结的很全面了，可以去百度一下）