List your Google Cloud Managed Service for Apache Kafka topics

To list your topics in a cluster, you can use the Google Cloud console, the Google Cloud CLI, the client library, the Managed Kafka API, or the open source Apache Kafka APIs.

Required roles and permissions to list your topics

To get the permissions that you need to list your topics, ask your administrator to grant you the Managed Kafka Viewer ( roles/managedkafka.viewer ) IAM role on your project. For more information about granting roles, see Manage access to projects, folders, and organizations .

This predefined role contains the permissions required to list your topics. To see the exact permissions that are required, expand the Required permissionssection:

Required permissions

The following permissions are required to list your topics:

List topics: managedkafka.topics.list
Get topic: managedkafka.topics.get

You might also be able to get these permissions with custom roles or other predefined roles .

For more information about the Managed Kafka Viewer ( roles/managedkafka.viewer ) IAM role, see Managed Service for Apache Kafka predefined roles .

List your topics

Console

In the Google Cloud console, go to the Clusters page.

Go to Clusters

The clusters you created in a project are listed.
Click the cluster for which you want to see the topics.
The cluster details page is displayed. In the cluster details page, for the Resources tab, the topics are listed.

gcloud

In the Google Cloud console, activate Cloud Shell.

Activate Cloud Shell

At the bottom of the Google Cloud console, a Cloud Shell session starts and displays a command-line prompt. Cloud Shell is a shell environment with the Google Cloud CLI already installed and with values already set for your current project. It can take a few seconds for the session to initialize.
Run the gcloud managed-kafka topics list command:
```
gcloud  
managed-kafka  
topics  
list  
 CLUSTER_ID 
  
 \ 
  
--location = 
 LOCATION_ID 
  
 \ 
  
--limit = 
 LIMIT 
```
This command retrieves a list of all topics present within the specified Managed Service for Apache Kafka cluster. You can use optional flags to filter, limit, and sort the output.

Replace the following:
- CLUSTER_ID : The name of the cluster whose topics you want to list.
- LOCATION_ID : The location of the cluster.
- LIMIT : (Optional) The maximum number of topics to list.

Go

Before trying this sample, follow the Go setup instructions in Install the 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(ADC). For more information, see Set up ADC 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 Install the 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 ADC 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 Install the client libraries . For more information, see the Managed Service for Apache Kafka Python API reference documentation .