Пример #1
0
// Watch runs Watch RPCs in parallel on the backends and returns a
// merged stream of results.
func (s *server) Watch(req *pb.Request, stream pb.Google_WatchServer) error { // HL
	ctx := stream.Context()
	c := make(chan result) // HL
	var wg sync.WaitGroup
	for _, b := range s.backends {
		wg.Add(1)
		go func(backend pb.GoogleClient) { // HL
			defer wg.Done()                    // HL
			watchBackend(ctx, backend, req, c) // HL
		}(b) // HL
	}
	go func() {
		wg.Wait()
		close(c) // HL
	}()
	for res := range c { // HL
		if res.err != nil {
			return res.err
		}
		if err := stream.Send(res.res); err != nil { // HL
			return err // HL
		} // HL
	}
	return nil
}
Пример #2
0
// Watch returns a stream of results identifying the query and this
// backend, sleeping a random interval between each send.
func (s *server) Watch(req *pb.Request, stream pb.Google_WatchServer) error { // HL
	ctx := stream.Context()
	for i := 0; ; i++ {
		d := randomDuration(1 * time.Second)
		logSleep(ctx, d) // HL
		select {
		case <-time.After(d):
			err := stream.Send(&pb.Result{ // HL
				Title: fmt.Sprintf("result %d for [%s] from backend %d", i, req.Query, *index), // HL
			}) // HL
			if err != nil {
				return err
			}
		case <-ctx.Done():
			return ctx.Err()
		}
	}
}