Create topic quickstart

Creates a topic.

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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 
 ) 
  
 { 
  
 auto 
  
 topic 
  
 = 
  
 client 
 . 
 CreateTopic 
 ( 
  
 pubsub 
 :: 
 Topic 
 ( 
 std 
 :: 
 move 
 ( 
 project_id 
 ), 
  
 std 
 :: 
 move 
 ( 
 topic_id 
 )). 
 FullName 
 ()); 
  
 // 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 
 " 
 ; 
 }

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 .

  // Sample pubsub-quickstart creates a Google Cloud Pub/Sub topic. 
 package 
  
 main 
 import 
  
 ( 
  
 "context" 
  
 "fmt" 
  
 "log" 
  
 "cloud.google.com/go/pubsub/v2" 
  
 "cloud.google.com/go/pubsub/v2/apiv1/pubsubpb" 
 ) 
 func 
  
 main 
 () 
  
 { 
  
 ctx 
  
 := 
  
 context 
 . 
 Background 
 () 
  
 // Sets your Google Cloud Platform project ID. 
  
 projectID 
  
 := 
  
 "YOUR_PROJECT_ID" 
  
 // Creates a client. 
  
 client 
 , 
  
 err 
  
 := 
  
 pubsub 
 . 
 NewClient 
 ( 
 ctx 
 , 
  
 projectID 
 ) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 log 
 . 
 Fatalf 
 ( 
 "Failed to create client: %v" 
 , 
  
 err 
 ) 
  
 } 
  
 defer 
  
 client 
 . 
 Close 
 () 
  
 // Sets the id for the new topic. 
  
 topicID 
  
 := 
  
 "my-topic" 
  
 pbTopic 
  
 := 
  
& pubsubpb 
 . 
 Topic 
 { 
  
 Name 
 : 
  
 fmt 
 . 
 Sprintf 
 ( 
 "projects/%s/topics/%s" 
 , 
  
 projectID 
 , 
  
 topicID 
 ), 
  
 } 
  
 // Creates the new topic. 
  
 topic 
 , 
  
 err 
  
 := 
  
 client 
 . 
 TopicAdminClient 
 . 
 CreateTopic 
 ( 
 ctx 
 , 
  
 pbTopic 
 ) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 log 
 . 
 Fatalf 
 ( 
 "Failed to create topic: %v" 
 , 
  
 err 
 ) 
  
 } 
  
 fmt 
 . 
 Printf 
 ( 
 "Topic %v created.\n" 
 , 
  
 topic 
 ) 
 }

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.pubsub.v1. Topic 
 
 ; 
 import 
  
 com.google.pubsub.v1. TopicName 
 
 ; 
 import 
  
 java.io.IOException 
 ; 
 public 
  
 class 
 CreateTopicExample 
  
 { 
  
 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" 
 ; 
  
 createTopicExample 
 ( 
 projectId 
 , 
  
 topicId 
 ); 
  
 } 
  
 public 
  
 static 
  
 void 
  
 createTopicExample 
 ( 
 String 
  
 projectId 
 , 
  
 String 
  
 topicId 
 ) 
  
 throws 
  
 IOException 
  
 { 
  
 try 
  
 ( 
  TopicAdminClient 
 
  
 topicAdminClient 
  
 = 
  
  TopicAdminClient 
 
 . 
 create 
 ()) 
  
 { 
  
  TopicName 
 
  
 topicName 
  
 = 
  
  TopicName 
 
 . 
 of 
 ( 
 projectId 
 , 
  
 topicId 
 ); 
  
  Topic 
 
  
 topic 
  
 = 
  
 topicAdminClient 
 . 
 createTopic 
 ( 
 topicName 
 ); 
  
 System 
 . 
 out 
 . 
 println 
 ( 
 "Created topic: " 
  
 + 
  
 topic 
 . 
  getName 
 
 ()); 
  
 } 
  
 } 
 }

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 .

  # Includes the autoloader for libraries installed with composer 
 require __DIR__ . '/vendor/autoload.php'; 
 # Imports the Google Cloud client library 
 use Google\Cloud\PubSub\PubSubClient; 
 # Your Google Cloud Platform project ID 
 $projectId = 'YOUR_PROJECT_ID'; 
 # Instantiates a client 
 $pubsub = new PubSubClient([ 
 'projectId' => $projectId 
 ]); 
 # The name for the new topic 
 $topicName = 'my-new-topic-2'; 
 # Creates the new topic 
 $topic = $pubsub->createTopic($topicName); 
 echo 'Topic ' . $topic->name() . ' created.';

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 .

  # Imports the Google Cloud client library 
 require 
  
 "google/cloud/pubsub" 
 # Instantiates a client 
 pubsub 
  
 = 
  
 Google 
 :: 
 Cloud 
 :: 
  PubSub 
 
 . 
  new 
 
 topic_admin 
  
 = 
  
 pubsub 
 . 
  topic_admin 
 
 # The name for the new topic 
 # topic_id = "your-topic-id" 
 # Creates the new topic 
 topic 
  
 = 
  
 topic_admin 
 . 
 create_topic 
  
 name 
 : 
  
 pubsub 
 . 
 topic_path 
 ( 
 topic_id 
 ) 
 puts 
  
 "Topic 
 #{ 
 topic 
 . 
 name 
 } 
 created."

What's next

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Explore further

Code sample

C++

Go

Java

PHP

Ruby

What's next

Create topic quickstart