1 原子锁
可以借助某个信号向所有的goroutine 发送消息

var (
	shotdown int64 // 该标志向多个goroutine通知状态
	wg       sync.WaitGroup
)

func main() {
	wg.Add(2)

	go doWork("A")
	go doWork("B")

	time.Sleep(1 * time.Second)

	atomic.StoreInt64(&shotdown, 1) // 修改
	wg.Wait()
}

func doWork(s string) {
	defer wg.Done()

	for {
		fmt.Printf("Doing homework %s\n", s)
		time.Sleep(2 * time.Second)

		if atomic.LoadInt64(&shotdown) == 1 { // 读取
			fmt.Printf("Shotdown home work %s\n", s)
			break
		}
	}
}

2 互斥锁
互斥锁,通过 mutex, 能够将一段临界区间包含起来,只运行单个goroutine执行

// 借助互斥锁实现同步访问共享资源
var (
	counter int
	wg      sync.WaitGroup
	mutex   sync.Mutex // 定义临界区
)

func main() {
	wg.Add(2)

	go incCount(1)
	go incCount(2)

	wg.Wait()
	fmt.Printf("Final Counter: %d\n", counter)
}

func incCount(i int) {
	defer wg.Done()

	for count := 0; count < 2; count++ {
		mutex.Lock()
		{
			value := counter
			runtime.Gosched()
			value++
			counter = value
		}
		mutex.Unlock()
	}
}