List the Kafka topics

Get a list of the Kafka topics

Explore further

For detailed documentation that includes this code sample, see the following:

• List your Google Cloud Managed Service for Apache Kafka topics

Code sample

Go

Before trying this sample, follow the Go setup instructions in the Managed Service for Apache Kafka quickstart using client libraries. For more information, see the Managed Service for Apache Kafka Go API reference documentation.

To authenticate to Managed Service for Apache Kafka, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import (
	"context"
	"fmt"
	"io"

	"cloud.google.com/go/managedkafka/apiv1/managedkafkapb"
	"google.golang.org/api/iterator"
	"google.golang.org/api/option"

	managedkafka "cloud.google.com/go/managedkafka/apiv1"
)

func listTopics(w io.Writer, projectID, region, clusterID string, opts ...option.ClientOption) error {
	// projectID := "my-project-id"
	// region := "us-central1"
	// clusterID := "my-cluster"
	ctx := context.Background()
	client, err := managedkafka.NewClient(ctx, opts...)
	if err != nil {
		return fmt.Errorf("managedkafka.NewClient got err: %w", err)
	}
	defer client.Close()

	clusterPath := fmt.Sprintf("projects/%s/locations/%s/clusters/%s", projectID, region, clusterID)
	req := &managedkafkapb.ListTopicsRequest{
		Parent: clusterPath,
	}
	topicIter := client.ListTopics(ctx, req)
	for {
		res, err := topicIter.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return fmt.Errorf("topicIter.Next() got err: %w", err)
		}
		fmt.Fprintf(w, "Got topic: %v", res)
	}
	return nil
}

Java

Before trying this sample, follow the Java setup instructions in the Managed Service for Apache Kafka quickstart using client libraries. For more information, see the Managed Service for Apache Kafka Java API reference documentation.

To authenticate to Managed Service for Apache Kafka, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import com.google.api.gax.rpc.ApiException;
import com.google.cloud.managedkafka.v1.ClusterName;
import com.google.cloud.managedkafka.v1.ManagedKafkaClient;
import com.google.cloud.managedkafka.v1.Topic;
import java.io.IOException;

public class ListTopics {

  public static void main(String[] args) throws Exception {
    // TODO(developer): Replace these variables before running the example.
    String projectId = "my-project-id";
    String region = "my-region"; // e.g. us-east1
    String clusterId = "my-cluster";
    listTopics(projectId, region, clusterId);
  }

  public static void listTopics(String projectId, String region, String clusterId)
      throws Exception {
    try (ManagedKafkaClient managedKafkaClient = ManagedKafkaClient.create()) {
      ClusterName clusterName = ClusterName.of(projectId, region, clusterId);
      // This operation is being handled synchronously.
      for (Topic topic : managedKafkaClient.listTopics(clusterName).iterateAll()) {
        System.out.println(topic.getAllFields());
      }
    } catch (IOException | ApiException e) {
      System.err.printf("managedKafkaClient.listTopics got err: %s", e.getMessage());
    }
  }
}

Python

Before trying this sample, follow the Python setup instructions in the Managed Service for Apache Kafka quickstart using client libraries. For more information, see the Managed Service for Apache Kafka Python API reference documentation.

To authenticate to Managed Service for Apache Kafka, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

from google.cloud import managedkafka_v1

# TODO(developer)
# project_id = "my-project-id"
# region = "us-central1"
# cluster_id = "my-cluster"

client = managedkafka_v1.ManagedKafkaClient()

request = managedkafka_v1.ListTopicsRequest(
    parent=client.cluster_path(project_id, region, cluster_id),
)

response = client.list_topics(request=request)
for topic in response:
    print("Got topic:", topic)

What's next

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