server side send response at least once per second

weed/mq/broker/broker_grpc_pub.go

@@ -7,6 +7,7 @@ import (
 	"github.com/seaweedfs/seaweedfs/weed/mq/topic"
 	"github.com/seaweedfs/seaweedfs/weed/pb"
 	"github.com/seaweedfs/seaweedfs/weed/pb/mq_pb"
+	"sync/atomic"
 	"time"
 )
 
@@ -99,20 +100,37 @@ func (broker *MessageQueueBroker) Publish(stream mq_pb.SeaweedMessaging_PublishS
 
 	ackCounter := 0
 	var ackSequence int64
+	var isStopping int32
 	respChan := make(chan *mq_pb.PublishResponse, 128)
-	defer close(respChan)
+	defer func() {
+		atomic.StoreInt32(&isStopping, 1)
+		response := &mq_pb.PublishResponse{
+			Error: "end of stream",
+		}
+		respChan <- response
+		close(respChan)
+	}()
 	go func() {
+		ticker := time.NewTicker(1 * time.Second)
 		for {
 			select {
 			case resp := <-respChan:
+				if resp != nil {
 					if err := stream.Send(resp); err != nil {
 						glog.Errorf("Error sending setup response: %v", err)
 					}
-			case <-time.After(1 * time.Second):
+				} else {
+					return
+				}
+			case <-ticker.C:
+				if atomic.LoadInt32(&isStopping) == 0 {
 					response := &mq_pb.PublishResponse{
 						AckSequence: ackSequence,
 					}
 					respChan <- response
+				} else {
+					return
+				}
 			}
 		}
 	}()