publisher is able to fully send data and receive acks

still needs to close the pipes cleanly

weed/mq/broker/broker_grpc_pub_follow.go

@@ -1,12 +1,49 @@
 package broker
 
 import (
-	"context"
+	"fmt"
 	"github.com/seaweedfs/seaweedfs/weed/glog"
 	"github.com/seaweedfs/seaweedfs/weed/pb/mq_pb"
+	"io"
 )
 
-func (b *MessageQueueBroker) PublishFollowMe(c context.Context, request *mq_pb.PublishFollowMeRequest) (*mq_pb.PublishFollowMeResponse, error) {
-	glog.V(0).Infof("PublishFollowMe %v", request)
-	return &mq_pb.PublishFollowMeResponse{}, nil
+func (b *MessageQueueBroker) PublishFollowMe(stream mq_pb.SeaweedMessaging_PublishFollowMeServer) error {
+	req, err := stream.Recv()
+	if err != nil {
+		return err
+	}
+	initMessage := req.GetInit()
+	if initMessage == nil {
+		return fmt.Errorf("missing init message")
+	}
+
+	// t, p := topic.FromPbTopic(initMessage.Topic), topic.FromPbPartition(initMessage.Partition)
+	// follow each published messages
+	for {
+		// receive a message
+		req, err := stream.Recv()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			glog.V(0).Infof("topic %v partition %v publish stream error: %v", initMessage.Topic, initMessage.Partition, err)
+			return err
+		}
+
+		// Process the received message
+		if dataMessage := req.GetData(); dataMessage != nil {
+			// send back the ack
+			if err := stream.Send(&mq_pb.PublishFollowMeResponse{
+				AckTsNs: dataMessage.TsNs,
+			}); err != nil {
+				// TODO save un-acked messages to disk
+				glog.Errorf("Error sending response %v: %v", dataMessage, err)
+			}
+			println("ack", string(dataMessage.Key), dataMessage.TsNs)
+		} else if closeMessage := req.GetClose(); closeMessage != nil {
+			glog.V(0).Infof("topic %v partition %v publish stream closed: %v", initMessage.Topic, initMessage.Partition, closeMessage)
+			break
+		}
+	}
+	return nil
 }