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    Update the topic schema

    Update the topic schema

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

    Code sample

    C++

    Before trying this sample, follow the C++ setup instructions in the Pub/Sub quickstart using client libraries . For more information, see the Pub/Sub C++ API reference documentation .

    To authenticate to Pub/Sub, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      namespace 
  
 pubsub 
  
 = 
  
 :: 
 google 
 :: 
 cloud 
 :: 
 pubsub 
 ; 
 namespace 
  
 pubsub_admin 
  
 = 
  
 :: 
 google 
 :: 
 cloud 
 :: 
 pubsub_admin 
 ; 
 []( 
 pubsub_admin 
 :: 
 TopicAdminClient 
  
 client 
 , 
  
 std 
 :: 
 string 
  
 project_id 
 , 
  
 std 
 :: 
 string 
  
 topic_id 
 , 
  
 std 
 :: 
 string 
  
 const 
&  
 first_revision_id 
 , 
  
 std 
 :: 
 string 
  
 const 
&  
 last_revision_id 
 ) 
  
 { 
  
 google 
 :: 
 pubsub 
 :: 
 v1 
 :: 
 UpdateTopicRequest 
  
 request 
 ; 
  
 auto 
 * 
  
 request_topic 
  
 = 
  
 request 
 . 
 mutable_topic 
 (); 
  
 request_topic 
 - 
> set_name 
 ( 
  
 pubsub 
 :: 
 Topic 
 ( 
 std 
 :: 
 move 
 ( 
 project_id 
 ), 
  
 std 
 :: 
 move 
 ( 
 topic_id 
 )). 
 FullName 
 ()); 
  
 request_topic 
 - 
> mutable_schema_settings 
 () 
 - 
> set_first_revision_id 
 ( 
  
 first_revision_id 
 ); 
  
 request_topic 
 - 
> mutable_schema_settings 
 () 
 - 
> set_last_revision_id 
 ( 
  
 last_revision_id 
 ); 
  
 * 
 request 
 . 
 mutable_update_mask 
 () 
 - 
> add_paths 
 () 
  
 = 
  
 "schema_settings.first_revision_id" 
 ; 
  
 * 
 request 
 . 
 mutable_update_mask 
 () 
 - 
> add_paths 
 () 
  
 = 
  
 "schema_settings.last_revision_id" 
 ; 
  
 auto 
  
 topic 
  
 = 
  
 client 
 . 
 UpdateTopic 
 ( 
 request 
 ); 
  
 if 
  
 ( 
 ! 
 topic 
 ) 
  
 throw 
  
 std 
 :: 
 move 
 ( 
 topic 
 ). 
 status 
 (); 
  
 std 
 :: 
 cout 
 << 
 "The topic was successfully updated: " 
 << 
 topic 
 - 
> DebugString 
 () 
 << 
 " 
 \n 
 " 
 ; 
 }

    C#

    Before trying this sample, follow the C# setup instructions in the Pub/Sub quickstart using client libraries . For more information, see the Pub/Sub C# API reference documentation .

    To authenticate to Pub/Sub, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      using 
  
  Google.Cloud.PubSub.V1 
 
 ; 
 using 
  
  Google.Protobuf.WellKnownTypes 
 
 ; 
 using 
  
 System 
 ; 
 public 
  
 class 
  
 UpdateTopicSchemaSample 
 { 
  
 public 
  
 Topic 
  
 UpdateTopicSchema 
 ( 
 string 
  
 projectId 
 , 
  
 string 
  
 topicId 
 , 
  
 string 
  
 firstRevisionId 
 , 
  
 string 
  
 lastRevisionId 
 ) 
  
 { 
  
  PublisherServiceApiClient 
 
  
 publisher 
  
 = 
  
  PublisherServiceApiClient 
 
 . 
  Create 
 
 (); 
  
 var 
  
 topicName 
  
 = 
  
  TopicName 
 
 . 
  FromProjectTopic 
 
 ( 
 projectId 
 , 
  
 topicId 
 ); 
  
  Topic 
 
  
 topic 
  
 = 
  
 new 
  
  Topic 
 
  
 { 
  
 TopicName 
  
 = 
  
 topicName 
 , 
  
 SchemaSettings 
  
 = 
  
 new 
  
  SchemaSettings 
 
  
 { 
  
 FirstRevisionId 
  
 = 
  
 firstRevisionId 
 , 
  
 LastRevisionId 
  
 = 
  
 lastRevisionId 
  
 } 
  
 }; 
  
  FieldMask 
 
  
 updateMask 
  
 = 
  
 new 
  
  FieldMask 
 
  
 { 
  
 Paths 
  
 = 
  
 { 
  
 "schema_settings.first_revision_id" 
 , 
  
 "schema_settings.last_revision_id" 
  
 } 
  
 }; 
  
  Topic 
 
  
 receivedTopic 
  
 = 
  
 publisher 
 . 
  UpdateTopic 
 
 ( 
 topic 
 , 
  
 updateMask 
 ); 
  
 Console 
 . 
 WriteLine 
 ( 
 $"Topic {topic. Name 
} updated." 
 ); 
  
 return 
  
 receivedTopic 
 ; 
  
 } 
 }

    Go

    Before trying this sample, follow the Go setup instructions in the Pub/Sub quickstart using client libraries . For more information, see the Pub/Sub Go API reference documentation .

    To authenticate to Pub/Sub, 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/pubsub/v2" 
  
 "cloud.google.com/go/pubsub/v2/apiv1/pubsubpb" 
  
 "google.golang.org/protobuf/types/known/fieldmaskpb" 
 ) 
 func 
  
 updateTopicSchema 
 ( 
 w 
  
 io 
 . 
 Writer 
 , 
  
 projectID 
 , 
  
 topicID 
 , 
  
 firstRevisionID 
 , 
  
 lastRevisionID 
  
 string 
 ) 
  
 error 
  
 { 
  
 // projectID := "my-project-id" 
  
 // topicID := "my-topic" // an existing topic that has schema settings attached to it. 
  
 // firstRevisionID := "my-revision-id" 
  
 // lastRevisionID := "my-revision-id" 
  
 ctx 
  
 := 
  
 context 
 . 
 Background 
 () 
  
 client 
 , 
  
 err 
  
 := 
  
 pubsub 
 . 
 NewClient 
 ( 
 ctx 
 , 
  
 projectID 
 ) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 return 
  
 fmt 
 . 
 Errorf 
 ( 
 "pubsub.NewClient: %w" 
 , 
  
 err 
 ) 
  
 } 
  
 // This updates the first / last revision ID for the topic's schema. 
  
 // To clear the schema entirely, use a zero valued (empty) SchemaSettings 
  
 // with the same field mask. 
  
 req 
  
 := 
  
& pubsubpb 
 . 
 UpdateTopicRequest 
 { 
  
 Topic 
 : 
  
& pubsubpb 
 . 
 Topic 
 { 
  
 Name 
 : 
  
 fmt 
 . 
 Sprintf 
 ( 
 "projects/%s/topics/%s" 
 , 
  
 projectID 
 , 
  
 topicID 
 ), 
  
 SchemaSettings 
 : 
  
& pubsubpb 
 . 
 SchemaSettings 
 { 
  
 FirstRevisionId 
 : 
  
 firstRevisionID 
 , 
  
 LastRevisionId 
 : 
  
 lastRevisionID 
 , 
  
 }, 
  
 }, 
  
 // Construct a field mask to indicate which field to update in the topic. 
  
 // Fields are specified relative to the topic 
  
 UpdateMask 
 : 
  
& fieldmaskpb 
 . 
 FieldMask 
 { 
  
 Paths 
 : 
  
 [] 
 string 
 { 
 "schema_settings.first_revision_id" 
 , 
  
 "schema_settings.last_revision_id" 
 }, 
  
 }, 
  
 } 
  
 gotTopicCfg 
 , 
  
 err 
  
 := 
  
 client 
 . 
 TopicAdminClient 
 . 
 UpdateTopic 
 ( 
 ctx 
 , 
  
 req 
 ) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 fmt 
 . 
 Fprintf 
 ( 
 w 
 , 
  
 "topic.Update err: %v\n" 
 , 
  
 gotTopicCfg 
 ) 
  
 return 
  
 err 
  
 } 
  
 fmt 
 . 
 Fprintf 
 ( 
 w 
 , 
  
 "Updated topic with schema: %#v\n" 
 , 
  
 gotTopicCfg 
 ) 
  
 return 
  
 nil 
 }

    Java

    Before trying this sample, follow the Java setup instructions in the Pub/Sub quickstart using client libraries . For more information, see the Pub/Sub Java API reference documentation .

    To authenticate to Pub/Sub, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      import 
  
 com.google.cloud.pubsub.v1. TopicAdminClient 
 
 ; 
 import 
  
 com.google.protobuf. FieldMask 
 
 ; 
 import 
  
 com.google.pubsub.v1. SchemaSettings 
 
 ; 
 import 
  
 com.google.pubsub.v1. Topic 
 
 ; 
 import 
  
 com.google.pubsub.v1. TopicName 
 
 ; 
 import 
  
 com.google.pubsub.v1. UpdateTopicRequest 
 
 ; 
 import 
  
 java.io.IOException 
 ; 
 public 
  
 class 
 UpdateTopicSchemaExample 
  
 { 
  
 public 
  
 static 
  
 void 
  
 main 
 ( 
 String 
 ... 
  
 args 
 ) 
  
 throws 
  
 Exception 
  
 { 
  
 // TODO(developer): Replace these variables before running the sample. 
  
 String 
  
 projectId 
  
 = 
  
 "your-project-id" 
 ; 
  
 // This is an existing topic that has schema settings attached to it. 
  
 String 
  
 topicId 
  
 = 
  
 "your-topic-id" 
 ; 
  
 // Set the minimum and maximum revsion ID 
  
 String 
  
 firstRevisionId 
  
 = 
  
 "your-revision-id" 
 ; 
  
 String 
  
 lastRevisionId 
  
 = 
  
 "your-revision-id" 
 ; 
  
 UpdateTopicSchemaExample 
 . 
 updateTopicSchemaExample 
 ( 
  
 projectId 
 , 
  
 topicId 
 , 
  
 firstRevisionId 
 , 
  
 lastRevisionId 
 ); 
  
 } 
  
 public 
  
 static 
  
 void 
  
 updateTopicSchemaExample 
 ( 
  
 String 
  
 projectId 
 , 
  
 String 
  
 topicId 
 , 
  
 String 
  
 firstRevisionid 
 , 
  
 String 
  
 lastRevisionId 
 ) 
  
 throws 
  
 IOException 
  
 { 
  
 try 
  
 ( 
  TopicAdminClient 
 
  
 topicAdminClient 
  
 = 
  
  TopicAdminClient 
 
 . 
 create 
 ()) 
  
 { 
  
  TopicName 
 
  
 topicName 
  
 = 
  
  TopicName 
 
 . 
 of 
 ( 
 projectId 
 , 
  
 topicId 
 ); 
  
 // Construct the schema settings with the changes you want to make. 
  
  SchemaSettings 
 
  
 schemaSettings 
  
 = 
  
  SchemaSettings 
 
 . 
 newBuilder 
 () 
  
 . 
  setFirstRevisionId 
 
 ( 
 firstRevisionid 
 ) 
  
 . 
  setLastRevisionId 
 
 ( 
 lastRevisionId 
 ) 
  
 . 
 build 
 (); 
  
 // Construct the topic with the schema settings you want to change. 
  
  Topic 
 
  
 topic 
  
 = 
  
  Topic 
 
 . 
 newBuilder 
 () 
  
 . 
 setName 
 ( 
 topicName 
 . 
  toString 
 
 ()) 
  
 . 
  setSchemaSettings 
 
 ( 
 schemaSettings 
 ) 
  
 . 
 build 
 (); 
  
 // Construct a field mask to indicate which field to update in the topic. 
  
  FieldMask 
 
  
 updateMask 
  
 = 
  
  FieldMask 
 
 . 
 newBuilder 
 () 
  
 . 
  addPaths 
 
 ( 
 "schema_settings.first_revision_id" 
 ) 
  
 . 
  addPaths 
 
 ( 
 "schema_settings.last_revision_id" 
 ) 
  
 . 
 build 
 (); 
  
  UpdateTopicRequest 
 
  
 request 
  
 = 
  
  UpdateTopicRequest 
 
 . 
 newBuilder 
 (). 
 setTopic 
 ( 
 topic 
 ). 
 setUpdateMask 
 ( 
 updateMask 
 ). 
 build 
 (); 
  
  Topic 
 
  
 response 
  
 = 
  
 topicAdminClient 
 . 
 updateTopic 
 ( 
 request 
 ); 
  
 System 
 . 
 out 
 . 
 println 
 ( 
 "Updated topic with schema: " 
  
 + 
  
 topic 
 . 
  getName 
 
 ()); 
  
 } 
  
 } 
 }

    Node.js

    Before trying this sample, follow the Node.js setup instructions in the Pub/Sub quickstart using client libraries . For more information, see the Pub/Sub Node.js API reference documentation .

    To authenticate to Pub/Sub, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      /** 
  
 * 
  
 TODO 
 ( 
 developer 
 ): 
  
 Uncomment 
  
 these 
  
 variables 
  
 before 
  
 running 
  
 the 
  
 sample 
 . 
  
 */ 
 // 
  
 const 
  
 topicNameOrId 
  
 = 
  
 'YOUR_TOPIC_NAME_OR_ID' 
 ; 
 // 
  
 const 
  
 firstRevisionId 
  
 = 
  
 'YOUR_REVISION_ID' 
 ; 
 // 
  
 const 
  
 lastRevisionId 
  
 = 
  
 'YOUR_REVISION_ID' 
 ; 
 // 
  
 Imports 
  
 the 
  
 Google 
  
 Cloud 
  
 client 
  
 library 
 const 
  
 { 
 PubSub 
 } 
  
 = 
  
 require 
 ( 
 '@google-cloud/pubsub' 
 ); 
 // 
  
 Creates 
  
 a 
  
 client 
 ; 
  
 cache 
  
 this 
  
 for 
  
 further 
  
 use 
 const 
  
 pubSubClient 
  
 = 
  
 new 
  
 PubSub 
 (); 
 async 
  
 function 
  
 updateTopicSchema 
 ( 
  
 topicNameOrId 
 , 
  
 firstRevisionId 
 , 
  
 lastRevisionId 
 , 
 ) 
  
 { 
  
 const 
  
 metadata 
  
 = 
  
 { 
  
 schemaSettings 
 : 
  
 { 
  
 firstRevisionId 
 , 
  
 lastRevisionId 
 , 
  
 }, 
  
 }; 
  
 await 
  
 pubSubClient 
 . 
 topic 
 ( 
 topicNameOrId 
 ) 
 . 
 setMetadata 
 ( 
 metadata 
 ); 
  
 console 
 . 
 log 
 ( 
 'Schema metadata updated successfully.' 
 ); 
 }

    Node.js

    Before trying this sample, follow the Node.js setup instructions in the Pub/Sub quickstart using client libraries . For more information, see the Pub/Sub Node.js API reference documentation .

    To authenticate to Pub/Sub, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      /** 
 * 
 TODO 
 ( 
 developer 
 ): 
 Uncomment 
 these 
 variables 
 before 
 running 
 the 
 sample 
 . 
 */ 
 // 
 const 
 topicNameOrId 
 = 
 'YOUR_TOPIC_NAME_OR_ID' 
 ; 
 // 
 const 
 firstRevisionId 
 = 
 'YOUR_REVISION_ID' 
 ; 
 // 
 const 
 lastRevisionId 
 = 
 'YOUR_REVISION_ID' 
 ; 
 // 
 Imports 
 the 
 Google 
 Cloud 
 client 
 library 
 import 
  
 { 
 PubSub 
 , 
 TopicMetadata 
 } 
 from 
  
 '@google-cloud/pubsub' 
 ; 
 // 
 Creates 
 a 
 client 
 ; 
 cache 
 this 
 for 
 further 
 use 
 const 
 pubSubClient 
 = 
 new 
 PubSub 
 (); 
 async 
 function 
 updateTopicSchema 
 ( 
 topicNameOrId 
 : 
 string 
 , 
 firstRevisionId 
 : 
 string 
 , 
 lastRevisionId 
 : 
 string 
 , 
 ) 
 { 
 const 
 metadata 
 : 
 TopicMetadata 
 = 
 { 
 schemaSettings 
 : 
 { 
 firstRevisionId 
 , 
 lastRevisionId 
 , 
 }, 
 }; 
 await 
 pubSubClient 
 . 
 topic 
 ( 
 topicNameOrId 
 ) 
 . 
 setMetadata 
 ( 
 metadata 
 ); 
 console 
 . 
 log 
 ( 
 'Schema metadata updated successfully.' 
 ); 
 }

    PHP

    Before trying this sample, follow the PHP setup instructions in the Pub/Sub quickstart using client libraries . For more information, see the Pub/Sub PHP API reference documentation .

    To authenticate to Pub/Sub, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      use Google\Cloud\PubSub\PubSubClient; 
 /** 
 * Update schema for a topic. 
 * 
 * @param string $projectId The ID of your Google Cloud Platform project. 
 * @param string $topicId The topic id of an existing topic that has schema 
 *        settings attached to it. 
 * @param string $firstRevisionId The minimum revision id 
 * @param string $lastRevisionId The maximum revision id 
 */ 
 function update_topic_schema( 
 string $projectId, 
 string $topicId, 
 string $firstRevisionId, 
 string $lastRevisionId, 
 ): void { 
 $pubsub = new PubSubClient([ 
 'projectId' => $projectId 
 ]); 
 $topic = $pubsub->topic($topicId); 
 $topic->update([ 
 'schemaSettings' => [ 
 // Minimum revision ID 
 'firstRevisionId' => $firstRevisionId, 
 // Maximum revision ID 
 'lastRevisionId' => $lastRevisionId 
 ] 
 ]); 
 printf('Updated topic with schema: %s', $topic->name()); 
 }

    Python

    Before trying this sample, follow the Python setup instructions in the Pub/Sub quickstart using client libraries . For more information, see the Pub/Sub Python API reference documentation .

    To authenticate to Pub/Sub, set up Application Default Credentials. For more information, see Set up authentication for a local development environment .

      from 
  
 google.api_core.exceptions 
  
 import 
 InvalidArgument 
 , 
 NotFound 
 from 
  
 google.cloud.pubsub 
  
 import 
  PublisherClient 
 
 # TODO(developer): Replace these variables before running the sample. 
 # project_id = "your-project-id" 
 # topic_id = "your-topic-id" 
 # first_revision_id = "your-revision-id" 
 # last_revision_id = "your-revision-id" 
 publisher_client 
 = 
 PublisherClient 
 () 
 topic_path 
 = 
  publisher_client 
 
 . 
 topic_path 
 ( 
 project_id 
 , 
 topic_id 
 ) 
 try 
 : 
 response 
 = 
  publisher_client 
 
 . 
 update_topic 
 ( 
 request 
 = 
 { 
 "topic" 
 : 
 { 
 "name" 
 : 
 topic_path 
 , 
 "schema_settings" 
 : 
 { 
 "first_revision_id" 
 : 
 first_revision_id 
 , 
 "last_revision_id" 
 : 
 last_revision_id 
 , 
 }, 
 }, 
 "update_mask" 
 : 
 "schemaSettings.firstRevisionId,schemaSettings.lastRevisionId" 
 , 
 } 
 ) 
 print 
 ( 
 f 
 "Updated a topic schema: 
 \n 
 { 
 response 
 } 
 " 
 ) 
 except 
 NotFound 
 : 
 print 
 ( 
 f 
 " 
 { 
 topic_id 
 } 
 not found." 
 ) 
 except 
 InvalidArgument 
 : 
 print 
 ( 
 "Schema settings are not valid." 
 )

    What's next

    To search and filter code samples for other Google Cloud products, see the Google Cloud sample browser .
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