[go学习笔记]二十五、go语言协程之任务的取消

更多学习笔记和示例代码请访问：github.com/wenjianzhan…

任务取消

利用channel close 的广播特性，可以对任务进行取消

func isCancelled(cancelChan chan struct{}) bool {
	select {
	case <-cancelChan:
		return true
	default:
		return false
	}
}

func cancel_1(cancelChan chan struct{}) {
	cancelChan <- struct{}{}
}

func cancel_2(cancelChan chan struct{}) {
	close(cancelChan)
}
func TestCancel(t *testing.T) {
	cancelChan := make(chan struct{}, 0)
	for i := 0; i < 5; i++ {
		go func(i int, cancelCh chan struct{}) {
			for {
				if isCancelled(cancelCh) {
					break
				}
				time.Sleep(time.Millisecond * 5)
			}
			fmt.Println(i, "Cancelled")

		}(i, cancelChan)
	}
	cancel_1(cancelChan)
	time.Sleep(time.Second * 1)
}

输出

=== RUN   TestCancel
4 Cancelled
--- PASS: TestCancel (1.00s)
PASS

Process finished with exit code 0

这时只取消了4 这个协程，因为只取消了1个，其他的都 break 掉了； 那我们对代码进行修改

func cancel_2(cancelChan chan struct{}) {
	close(cancelChan)
}
func TestCancel(t *testing.T) {
	cancelChan := make(chan struct{}, 0)
	for i := 0; i < 5; i++ {
		go func(i int, cancelCh chan struct{}) {
			for {
				if isCancelled(cancelCh) {
					break
				}
				time.Sleep(time.Millisecond * 5)
			}
			fmt.Println(i, "Cancelled")

		}(i, cancelChan)
	}
	cancel_2(cancelChan)
	time.Sleep(time.Second * 1)
}

输出

=== RUN   TestCancel
1 Cancelled
4 Cancelled
2 Cancelled
3 Cancelled
0 Cancelled
--- PASS: TestCancel (1.00s)
PASS

Process finished with exit code 0

五个协程全部取消了

更多学习笔记和示例代码请访问：github.com/wenjianzhan…