Create a schema when you create a topic

Create a topic and also create a schema.

Explore further

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

Associate a schema with a topic

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 
  
 schema_id 
 , 
  
 std 
 :: 
 string 
  
 const 
&  
 encoding 
 ) 
  
 { 
  
 google 
 :: 
 pubsub 
 :: 
 v1 
 :: 
 Topic 
  
 request 
 ; 
  
 request 
 . 
 set_name 
 ( 
 pubsub 
 :: 
 Topic 
 ( 
 project_id 
 , 
  
 std 
 :: 
 move 
 ( 
 topic_id 
 )). 
 FullName 
 ()); 
  
 request 
 . 
 mutable_schema_settings 
 () 
 - 
> set_schema 
 ( 
  
 pubsub 
 :: 
 Schema 
 ( 
 std 
 :: 
 move 
 ( 
 project_id 
 ), 
  
 std 
 :: 
 move 
 ( 
 schema_id 
 )). 
 FullName 
 ()); 
  
 request 
 . 
 mutable_schema_settings 
 () 
 - 
> set_encoding 
 ( 
  
 encoding 
  
 == 
  
 "JSON" 
  
 ? 
  
 google 
 :: 
 pubsub 
 :: 
 v1 
 :: 
 JSON 
  
 : 
  
 google 
 :: 
 pubsub 
 :: 
 v1 
 :: 
 BINARY 
 ); 
  
 auto 
  
 topic 
  
 = 
  
 client 
 . 
 CreateTopic 
 ( 
 request 
 ); 
  
 // Note that kAlreadyExists is a possible error when the library retries. 
  
 if 
  
 ( 
 topic 
 . 
 status 
 (). 
 code 
 () 
  
 == 
  
 google 
 :: 
 cloud 
 :: 
 StatusCode 
 :: 
 kAlreadyExists 
 ) 
  
 { 
  
 std 
 :: 
 cout 
 << 
 "The topic already exists 
 \n 
 " 
 ; 
  
 return 
 ; 
  
 } 
  
 if 
  
 ( 
 ! 
 topic 
 ) 
  
 throw 
  
 std 
 :: 
 move 
 ( 
 topic 
 ). 
 status 
 (); 
  
 std 
 :: 
 cout 
 << 
 "The topic was successfully created: " 
 << 
 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 
  
  Grpc.Core 
 
 ; 
 using 
  
 System 
 ; 
 public 
  
 class 
  
 CreateTopicWithSchemaSample 
 { 
  
 public 
  
 Topic 
  
 CreateTopicWithSchema 
 ( 
 string 
  
 projectId 
 , 
  
 string 
  
 topicId 
 , 
  
 string 
  
 schemaId 
 , 
  
  Encoding 
 
  
 encoding 
 ) 
  
 { 
  
  PublisherServiceApiClient 
 
  
 publisher 
  
 = 
  
  PublisherServiceApiClient 
 
 . 
  Create 
 
 (); 
  
 var 
  
 topicName 
  
 = 
  
  TopicName 
 
 . 
  FromProjectTopic 
 
 ( 
 projectId 
 , 
  
 topicId 
 ); 
  
  Topic 
 
  
 topic 
  
 = 
  
 new 
  
  Topic 
 
  
 { 
  
 TopicName 
  
 = 
  
 topicName 
 , 
  
 SchemaSettings 
  
 = 
  
 new 
  
  SchemaSettings 
 
  
 { 
  
 SchemaAsSchemaName 
  
 = 
  
  SchemaName 
 
 . 
  FromProjectSchema 
 
 ( 
 projectId 
 , 
  
 schemaId 
 ), 
  
 Encoding 
  
 = 
  
 encoding 
  
 } 
  
 }; 
  
  Topic 
 
  
 receivedTopic 
  
 = 
  
 null 
 ; 
  
 try 
  
 { 
  
 receivedTopic 
  
 = 
  
 publisher 
 . 
  CreateTopic 
 
 ( 
 topic 
 ); 
  
 Console 
 . 
 WriteLine 
 ( 
 $"Topic {topic. Name 
} created." 
 ); 
  
 } 
  
 catch 
  
 ( 
  RpcException 
 
  
 e 
 ) 
  
 when 
  
 ( 
 e 
 . 
  Status 
 
 . 
  StatusCode 
 
  
 == 
  
  StatusCode 
 
 . 
  AlreadyExists 
 
 ) 
  
 { 
  
 Console 
 . 
 WriteLine 
 ( 
 $"Topic {topicName} already exists." 
 ); 
  
 } 
  
 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" 
 ) 
 func 
  
 createTopicWithSchema 
 ( 
 w 
  
 io 
 . 
 Writer 
 , 
  
 projectID 
 , 
  
 topicID 
 , 
  
 schemaID 
  
 string 
 , 
  
 encoding 
  
 pubsubpb 
 . 
 Encoding 
 ) 
  
 error 
  
 { 
  
 // projectID := "my-project-id" 
  
 // topicID := "my-topic" 
  
 // schemaID := "my-schema-id" 
  
 // encoding := pubsub.EncodingJSON 
  
 ctx 
  
 := 
  
 context 
 . 
 Background 
 () 
  
 client 
 , 
  
 err 
  
 := 
  
 pubsub 
 . 
 NewClient 
 ( 
 ctx 
 , 
  
 projectID 
 ) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 return 
  
 fmt 
 . 
 Errorf 
 ( 
 "pubsub.NewClient: %w" 
 , 
  
 err 
 ) 
  
 } 
  
 topic 
  
 := 
  
& pubsubpb 
 . 
 Topic 
 { 
  
 Name 
 : 
  
 fmt 
 . 
 Sprintf 
 ( 
 "projects/%s/topics/%s" 
 , 
  
 projectID 
 , 
  
 topicID 
 ), 
  
 SchemaSettings 
 : 
  
& pubsubpb 
 . 
 SchemaSettings 
 { 
  
 Schema 
 : 
  
 fmt 
 . 
 Sprintf 
 ( 
 "projects/%s/schemas/%s" 
 , 
  
 projectID 
 , 
  
 schemaID 
 ), 
  
 Encoding 
 : 
  
 encoding 
 , 
  
 }, 
  
 } 
  
 t 
 , 
  
 err 
  
 := 
  
 client 
 . 
 TopicAdminClient 
 . 
 CreateTopic 
 ( 
 ctx 
 , 
  
 topic 
 ) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 return 
  
 fmt 
 . 
 Errorf 
 ( 
 "CreateTopicWithConfig: %w" 
 , 
  
 err 
 ) 
  
 } 
  
 fmt 
 . 
 Fprintf 
 ( 
 w 
 , 
  
 "Topic with schema created: %#v\n" 
 , 
  
 t 
 ) 
  
 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.api.gax.rpc. AlreadyExistsException 
 
 ; 
 import 
  
 com.google.cloud.pubsub.v1. TopicAdminClient 
 
 ; 
 import 
  
 com.google.pubsub.v1. Encoding 
 
 ; 
 import 
  
 com.google.pubsub.v1. SchemaName 
 
 ; 
 import 
  
 com.google.pubsub.v1. SchemaSettings 
 
 ; 
 import 
  
 com.google.pubsub.v1. Topic 
 
 ; 
 import 
  
 com.google.pubsub.v1. TopicName 
 
 ; 
 import 
  
 java.io.IOException 
 ; 
 public 
  
 class 
 CreateTopicWithSchemaExample 
  
 { 
  
 public 
  
 static 
  
 void 
  
 main 
 ( 
 String 
 ... 
  
 args 
 ) 
  
 throws 
  
 Exception 
  
 { 
  
 // TODO(developer): Replace these variables before running the sample. 
  
 String 
  
 projectId 
  
 = 
  
 "your-project-id" 
 ; 
  
 String 
  
 topicId 
  
 = 
  
 "your-topic-id" 
 ; 
  
 // Use an existing schema. 
  
 String 
  
 schemaId 
  
 = 
  
 "your-schema-id" 
 ; 
  
 // Choose either BINARY or JSON message serialization in this topic. 
  
  Encoding 
 
  
 encoding 
  
 = 
  
  Encoding 
 
 . 
 BINARY 
 ; 
  
 createTopicWithSchemaExample 
 ( 
 projectId 
 , 
  
 topicId 
 , 
  
 schemaId 
 , 
  
 encoding 
 ); 
  
 } 
  
 public 
  
 static 
  
 void 
  
 createTopicWithSchemaExample 
 ( 
  
 String 
  
 projectId 
 , 
  
 String 
  
 topicId 
 , 
  
 String 
  
 schemaId 
 , 
  
  Encoding 
 
  
 encoding 
 ) 
  
 throws 
  
 IOException 
  
 { 
  
  TopicName 
 
  
 topicName 
  
 = 
  
  TopicName 
 
 . 
 of 
 ( 
 projectId 
 , 
  
 topicId 
 ); 
  
  SchemaName 
 
  
 schemaName 
  
 = 
  
  SchemaName 
 
 . 
 of 
 ( 
 projectId 
 , 
  
 schemaId 
 ); 
  
  SchemaSettings 
 
  
 schemaSettings 
  
 = 
  
  SchemaSettings 
 
 . 
 newBuilder 
 (). 
 setSchema 
 ( 
 schemaName 
 . 
  toString 
 
 ()). 
 setEncoding 
 ( 
 encoding 
 ). 
 build 
 (); 
  
 try 
  
 ( 
  TopicAdminClient 
 
  
 topicAdminClient 
  
 = 
  
  TopicAdminClient 
 
 . 
 create 
 ()) 
  
 { 
  
  Topic 
 
  
 topic 
  
 = 
  
 topicAdminClient 
 . 
 createTopic 
 ( 
  
  Topic 
 
 . 
 newBuilder 
 () 
  
 . 
 setName 
 ( 
 topicName 
 . 
  toString 
 
 ()) 
  
 . 
  setSchemaSettings 
 
 ( 
 schemaSettings 
 ) 
  
 . 
 build 
 ()); 
  
 System 
 . 
 out 
 . 
 println 
 ( 
 "Created topic with schema: " 
  
 + 
  
 topic 
 . 
  getName 
 
 ()); 
  
 } 
  
 catch 
  
 ( 
  AlreadyExistsException 
 
  
 e 
 ) 
  
 { 
  
 System 
 . 
 out 
 . 
 println 
 ( 
 schemaName 
  
 + 
  
 "already exists." 
 ); 
  
 } 
  
 } 
 }

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 
  
 schemaName 
  
 = 
  
 'YOUR_SCHEMA_NAME_OR_ID' 
 ; 
 // 
  
 const 
  
 encodingType 
  
 = 
  
 'BINARY' 
 ; 
 // 
  
 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 
  
 createTopicWithSchema 
 ( 
  
 topicNameOrId 
 , 
  
 schemaNameOrId 
 , 
  
 encodingType 
 , 
 ) 
  
 { 
  
 // 
  
 Get 
  
 the 
  
 fully 
  
 qualified 
  
 schema 
  
 name 
 . 
  
 const 
  
 schema 
  
 = 
  
 pubSubClient 
 . 
 schema 
 ( 
 schemaNameOrId 
 ); 
  
 const 
  
 fullName 
  
 = 
  
 await 
  
 schema 
 . 
 getName 
 (); 
  
 // 
  
 Creates 
  
 a 
  
 new 
  
 topic 
  
 with 
  
 a 
  
 schema 
 . 
  
 Note 
  
 that 
  
 you 
  
 might 
  
 also 
  
 // 
  
 pass 
  
 Encodings 
 . 
 Json 
  
 or 
  
 Encodings 
 . 
 Binary 
  
 here 
 . 
  
 await 
  
 pubSubClient 
 . 
 createTopic 
 ({ 
  
 name 
 : 
  
 topicNameOrId 
 , 
  
 schemaSettings 
 : 
  
 { 
  
 schema 
 : 
  
 fullName 
 , 
  
 encoding 
 : 
  
 encodingType 
 , 
  
 }, 
  
 }); 
  
 console 
 . 
 log 
 ( 
 ` 
 Topic 
  
 $ 
 { 
 topicNameOrId 
 } 
  
 created 
  
 with 
  
 schema 
  
 $ 
 { 
 fullName 
 } 
 . 
 ` 
 ); 
 }

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 
 schemaName 
 = 
 'YOUR_SCHEMA_NAME_OR_ID' 
 ; 
 // 
 const 
 encodingType 
 = 
 'BINARY' 
 ; 
 // 
 Imports 
 the 
 Google 
 Cloud 
 client 
 library 
 import 
  
 { 
 PubSub 
 } 
 from 
  
 '@google-cloud/pubsub' 
 ; 
 // 
 Creates 
 a 
 client 
 ; 
 cache 
 this 
 for 
 further 
 use 
 const 
 pubSubClient 
 = 
 new 
 PubSub 
 (); 
 async 
 function 
 createTopicWithSchema 
 ( 
 topicNameOrId 
 : 
 string 
 , 
 schemaNameOrId 
 : 
 string 
 , 
 encodingType 
 : 
 'BINARY' 
 | 
 'JSON' 
 , 
 ) 
 { 
 // 
 Get 
 the 
 fully 
 qualified 
 schema 
 name 
 . 
 const 
 schema 
 = 
 pubSubClient 
 . 
 schema 
 ( 
 schemaNameOrId 
 ); 
 const 
 fullName 
 = 
 await 
 schema 
 . 
 getName 
 (); 
 // 
 Creates 
 a 
 new 
 topic 
 with 
 a 
 schema 
 . 
 Note 
 that 
 you 
 might 
 also 
 // 
 pass 
 Encodings 
 . 
 Json 
 or 
 Encodings 
 . 
 Binary 
 here 
 . 
 await 
 pubSubClient 
 . 
 createTopic 
 ({ 
 name 
 : 
 topicNameOrId 
 , 
 schemaSettings 
 : 
 { 
 schema 
 : 
 fullName 
 , 
 encoding 
 : 
 encodingType 
 , 
 }, 
 }); 
 console 
 . 
 log 
 ( 
 ` 
 Topic 
 $ 
 { 
 topicNameOrId 
 } 
 created 
 with 
 schema 
 $ 
 { 
 fullName 
 } 
 . 
 ` 
 ); 
 }

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; 
 use Google\Cloud\PubSub\Schema; 
 /** 
 * Create a topic with a schema. 
 * 
 * @param string $projectId 
 * @param string $topicId 
 * @param string $schemaId 
 * @param string $encoding 
 */ 
 function create_topic_with_schema($projectId, $topicId, $schemaId, $encoding) 
 { 
 $pubsub = new PubSubClient([ 
 'projectId' => $projectId, 
 ]); 
 $schema = $pubsub->schema($schemaId); 
 $topic = $pubsub->createTopic($topicId, [ 
 'schemaSettings' => [ 
 // The schema may be provided as an instance of the schema type, 
 // or by using the schema ID directly. 
 'schema' => $schema, 
 // Encoding may be either `BINARY` or `JSON`. 
 // Provide a string or a constant from Google\Cloud\PubSub\V1\Encoding. 
 'encoding' => $encoding, 
 ] 
 ]); 
 printf('Topic %s created', $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 
 AlreadyExists 
 , 
 InvalidArgument 
 from 
  
 google.cloud.pubsub 
  
 import 
  PublisherClient 
 
 , 
 SchemaServiceClient 
 from 
  
 google.pubsub_v1.types 
  
 import 
 Encoding 
 # TODO(developer): Replace these variables before running the sample. 
 # project_id = "your-project-id" 
 # topic_id = "your-topic-id" 
 # schema_id = "your-schema-id" 
 # Choose either BINARY or JSON as valid message encoding in this topic. 
 # message_encoding = "BINARY" 
 publisher_client 
 = 
 PublisherClient 
 () 
 topic_path 
 = 
  publisher_client 
 
 . 
 topic_path 
 ( 
 project_id 
 , 
 topic_id 
 ) 
 schema_client 
 = 
 SchemaServiceClient 
 () 
 schema_path 
 = 
 schema_client 
 . 
  schema_path 
 
 ( 
 project_id 
 , 
 schema_id 
 ) 
 if 
 message_encoding 
 == 
 "BINARY" 
 : 
 encoding 
 = 
 Encoding 
 . 
 BINARY 
 elif 
 message_encoding 
 == 
 "JSON" 
 : 
 encoding 
 = 
 Encoding 
 . 
 JSON 
 else 
 : 
 encoding 
 = 
 Encoding 
 . 
 ENCODING_UNSPECIFIED 
 try 
 : 
 response 
 = 
  publisher_client 
 
 . 
 create_topic 
 ( 
 request 
 = 
 { 
 "name" 
 : 
 topic_path 
 , 
 "schema_settings" 
 : 
 { 
 "schema" 
 : 
 schema_path 
 , 
 "encoding" 
 : 
 encoding 
 }, 
 } 
 ) 
 print 
 ( 
 f 
 "Created a topic: 
 \n 
 { 
 response 
 } 
 " 
 ) 
 except 
 AlreadyExists 
 : 
 print 
 ( 
 f 
 " 
 { 
 topic_id 
 } 
 already exists." 
 ) 
 except 
 InvalidArgument 
 : 
 print 
 ( 
 "Schema settings are not valid." 
 )

Ruby

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

  # topic_id = "your-topic-id" 
 # schema_id = "your-schema-id" 
 # Choose either BINARY or JSON as valid message encoding in this topic. 
 # message_encoding = :BINARY 
 pubsub 
  
 = 
  
 Google 
 :: 
 Cloud 
 :: 
  PubSub 
 
 . 
  new 
 
 topic_admin 
  
 = 
  
 pubsub 
 . 
  topic_admin 
 
 topic 
  
 = 
  
 topic_admin 
 . 
 create_topic 
  
 name 
 : 
  
 pubsub 
 . 
 topic_path 
 ( 
 topic_id 
 ), 
  
 schema_settings 
 : 
  
 { 
  
 schema 
 : 
  
 pubsub 
 . 
 schema_path 
 ( 
 schema_id 
 ), 
  
 encoding 
 : 
  
 message_encoding 
  
 } 
 puts 
  
 "Topic 
 #{ 
 topic 
 . 
 name 
 } 
 created."

What's next

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

Create a schema when you create a topic Stay organized with collections Save and categorize content based on your preferences.

Explore further

Code sample

C++

C#

Go

Java

Node.js

Node.js

PHP

Python

Ruby

What's next

Create a schema when you create a topic