golang-context

ctx.go

package gomarker

type service func() result

func invokeService(ctx content.Content, s service) chan result {
	c := make(chan result)
	go func() {
		c1 := make(chan result)
		go func() {
			c1 <- s()
		}()
		select {
		case v := <-c1:
			c <- v
		case <-ctx.Done():
			// cancel this in-flight request by closing its connection.
		}
	}()
	return c
}

func handleRequestByDAM() {
	ctx, cf := context.WithCancel(context.Background())
	c1, c2, c3 := invokeService(ctx, service1), invokeService(ctx, service2),
		invokeService(ctx, service3)
	timeout := time.After(200 * time.Millisecond)
	for   {
		select {
		case r := <-c1:
		//handle result1
		case r := <-c2:
		//handle result2
		case r := <-c3:
		//handle result3
		case <-timeout:
			cf() // cancel all service invoke requests
			return
		}
	}
	return
}