describe a topic

weed/shell/command_mq_topic_desc.go

@@ -0,0 +1,59 @@
+package shell
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"github.com/seaweedfs/seaweedfs/weed/pb"
+	"github.com/seaweedfs/seaweedfs/weed/pb/mq_pb"
+	"io"
+)
+
+func init() {
+	Commands = append(Commands, &commandMqTopicDescribe{})
+}
+
+type commandMqTopicDescribe struct {
+}
+
+func (c *commandMqTopicDescribe) Name() string {
+	return "mq.topic.describe"
+}
+
+func (c *commandMqTopicDescribe) Help() string {
+	return `describe a topic`
+}
+
+func (c *commandMqTopicDescribe) Do(args []string, commandEnv *CommandEnv, writer io.Writer) error {
+	// parse parameters
+	mqCommand := flag.NewFlagSet(c.Name(), flag.ContinueOnError)
+	namespace := mqCommand.String("namespace", "", "namespace name")
+	topicName := mqCommand.String("topic", "", "topic name")
+	if err := mqCommand.Parse(args); err != nil {
+		return err
+	}
+
+	// find the broker balancer
+	brokerBalancer, err := findBrokerBalancer(commandEnv)
+	if err != nil {
+		return err
+	}
+	fmt.Fprintf(writer, "current balancer: %s\n", brokerBalancer)
+
+	return pb.WithBrokerGrpcClient(false, brokerBalancer, commandEnv.option.GrpcDialOption, func(client mq_pb.SeaweedMessagingClient) error {
+		resp, err := client.LookupTopicBrokers(context.Background(), &mq_pb.LookupTopicBrokersRequest{
+			Topic: &mq_pb.Topic{
+				Namespace: *namespace,
+				Name:      *topicName,
+			},
+			IsForPublish: false,
+		})
+		if err != nil {
+			return err
+		}
+		for _, assignment := range resp.BrokerPartitionAssignments {
+			fmt.Fprintf(writer, "  %+v\n", assignment)
+		}
+		return nil
+	})
+}