add CreateTopic API

weed/mq/broker/broker_grpc_lookup.go

@@ -7,6 +7,26 @@ import (
 	"google.golang.org/grpc/status"
 )
 
+func (broker *MessageQueueBroker) CreateTopic(ctx context.Context, request *mq_pb.CreateTopicRequest) (resp *mq_pb.CreateTopicResponse, err error) {
+	if broker.currentBalancer == "" {
+		return nil, status.Errorf(codes.Unavailable, "no balancer")
+	}
+	if !broker.lockAsBalancer.IsLocked() {
+		proxyErr := broker.withBrokerClient(false, broker.currentBalancer, func(client mq_pb.SeaweedMessagingClient) error {
+			resp, err = client.CreateTopic(ctx, request)
+			return nil
+		})
+		if proxyErr != nil {
+			return nil, proxyErr
+		}
+		return resp, err
+	}
+
+	ret := &mq_pb.CreateTopicResponse{}
+	ret.BrokerPartitionAssignments, err = broker.Balancer.LookupOrAllocateTopicPartitions(request.Topic, true)
+	return ret, err
+}
+
 // FindTopicBrokers returns the brokers that are serving the topic
 //
 //  1. lock the topic