messaging: able to pub sub multiple partitions

weed/messaging/client/publisher.go

@@ -3,14 +3,38 @@ package client
 import (
 	"context"
 
+	"github.com/OneOfOne/xxhash"
+
 	"github.com/chrislusf/seaweedfs/weed/pb/messaging_pb"
 )
 
 type Publisher struct {
-	publishClient messaging_pb.SeaweedMessaging_PublishClient
+	publishClients     []messaging_pb.SeaweedMessaging_PublishClient
+	topicConfiguration *messaging_pb.TopicConfiguration
+	messageCount       uint64
+	publisherId        string
 }
 
-func (mc *MessagingClient) NewPublisher(namespace, topic string) (*Publisher, error) {
+func (mc *MessagingClient) NewPublisher(publisherId, namespace, topic string) (*Publisher, error) {
+	// read topic configuration
+	topicConfiguration := &messaging_pb.TopicConfiguration{
+		PartitionCount: 4,
+	}
+	publishClients := make([]messaging_pb.SeaweedMessaging_PublishClient, topicConfiguration.PartitionCount)
+	for i := 0; i < int(topicConfiguration.PartitionCount); i++ {
+		client, err := mc.setupPublisherClient(namespace, topic, int32(i))
+		if err != nil {
+			return nil, err
+		}
+		publishClients[i] = client
+	}
+	return &Publisher{
+		publishClients:     publishClients,
+		topicConfiguration: topicConfiguration,
+	}, nil
+}
+
+func (mc *MessagingClient) setupPublisherClient(namespace, topic string, partition int32) (messaging_pb.SeaweedMessaging_PublishClient, error) {
 
 	stream, err := messaging_pb.NewSeaweedMessagingClient(mc.grpcConnection).Publish(context.Background())
 	if err != nil {
@@ -22,7 +46,7 @@ func (mc *MessagingClient) NewPublisher(namespace, topic string) (*Publisher, er
 		Init: &messaging_pb.PublishRequest_InitMessage{
 			Namespace: namespace,
 			Topic:     topic,
-			Partition: 0,
+			Partition: partition,
 		},
 	})
 	if err != nil {
@@ -56,20 +80,34 @@ func (mc *MessagingClient) NewPublisher(namespace, topic string) (*Publisher, er
 		}
 	}()
 
-	return &Publisher{
-		publishClient: stream,
-	}, nil
+	return stream, nil
+
 }
 
 func (p *Publisher) Publish(m *messaging_pb.Message) error {
+	hashValue := p.messageCount
+	p.messageCount++
+	if p.topicConfiguration.Partitoning == messaging_pb.TopicConfiguration_NonNullKeyHash {
+		if m.Key != nil {
+			hashValue = xxhash.Checksum64(m.Key)
+		}
+	} else if p.topicConfiguration.Partitoning == messaging_pb.TopicConfiguration_KeyHash {
+		hashValue = xxhash.Checksum64(m.Key)
+	} else {
+		// round robin
+	}
 
-	return p.publishClient.Send(&messaging_pb.PublishRequest{
+	idx := int(hashValue) % len(p.publishClients)
+	if idx < 0 {
+		idx += len(p.publishClients)
+	}
+	return p.publishClients[idx].Send(&messaging_pb.PublishRequest{
 		Data: m,
 	})
-
 }
 
-func (p *Publisher) Close() error {
-
-	return p.publishClient.CloseSend()
+func (p *Publisher) Shutdown() {
+	for _, client := range p.publishClients {
+		client.CloseSend()
+	}
 }