Diese Seite wurde von der Cloud Translation API übersetzt.

Thema bearbeiten, um ein Schema zu verknüpfen

Thema bearbeiten Verknüpfen Sie ein Schema und geben Sie Versionen an.

Weitere Informationen

Eine ausführliche Dokumentation, die dieses Codebeispiel enthält, finden Sie hier:

Schema mit einem Thema verknüpfen

Codebeispiel

C++

Folgen Sie der Einrichtungsanleitung für C++ in der Kurzanleitung zur Verwendung von Clientbibliotheken, bevor Sie dieses Beispiel anwenden. Weitere Informationen finden Sie in der Pub/Sub C++ API Referenzdokumentation.

Richten Sie Standardanmeldedaten für Anwendungen ein, um sich bei Pub/Sub zu authentifizieren. Weitere Informationen finden Sie unter Authentifizierung für eine lokale Entwicklungsumgebung einrichten.

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,
   std::string const& first_revision_id,
   std::string const& last_revision_id) {
  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);
  request.mutable_schema_settings()->set_first_revision_id(first_revision_id);
  request.mutable_schema_settings()->set_last_revision_id(last_revision_id);
  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#

Folgen Sie der Einrichtungsanleitung für C# in der Kurzanleitung zur Verwendung von Clientbibliotheken, bevor Sie dieses Beispiel anwenden. Weitere Informationen finden Sie in der Referenzdokumentation zur Pub/Sub C# API.


using Google.Cloud.PubSub.V1;
using Grpc.Core;
using System;

public class CreateTopicWithSchemaRevisionsSample
{
    public Topic CreateTopicWithSchemaRevisions(string projectId, string topicId, string schemaId, string firstRevisionId, string lastRevisionId, 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),
                FirstRevisionId = firstRevisionId,
                LastRevisionId = lastRevisionId,
                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

Bevor Sie dieses Beispiel ausprobieren, folgen Sie der Einrichtungsanleitung für Go in der Pub/Sub-Schnellstart mit Clientbibliotheken. Weitere Informationen finden Sie in der Referenzdokumentation zur Pub/Sub Go API.

Richten Sie die Standardanmeldedaten für Anwendungen ein, um sich bei Pub/Sub zu authentifizieren. Weitere Informationen finden Sie unter Authentifizierung für eine lokale Entwicklungsumgebung einrichten.

import (
	"context"
	"fmt"
	"io"

	"cloud.google.com/go/pubsub"
)

func createTopicWithSchemaRevisions(w io.Writer, projectID, topicID, schemaID, firstRevisionID, lastRevisionID string, encoding pubsub.SchemaEncoding) error {
	// projectID := "my-project-id"
	// topicID := "my-topic"
	// schemaID := "my-schema-id"
	// firstRevisionID := "my-revision-id"
	// lastRevisionID := "my-revision-id"
	// encoding := pubsub.EncodingJSON
	ctx := context.Background()
	client, err := pubsub.NewClient(ctx, projectID)
	if err != nil {
		return fmt.Errorf("pubsub.NewClient: %w", err)
	}

	tc := &pubsub.TopicConfig{
		SchemaSettings: &pubsub.SchemaSettings{
			Schema:          fmt.Sprintf("projects/%s/schemas/%s", projectID, schemaID),
			FirstRevisionID: firstRevisionID,
			LastRevisionID:  lastRevisionID,
			Encoding:        encoding,
		},
	}
	t, err := client.CreateTopicWithConfig(ctx, topicID, tc)
	if err != nil {
		return fmt.Errorf("CreateTopicWithConfig: %w", err)
	}
	fmt.Fprintf(w, "Created topic with schema revision: %#v\n", t)
	return nil
}

Java

Folgen Sie der Einrichtungsanleitung für Java in der Kurzanleitung zur Verwendung von Clientbibliotheken, bevor Sie dieses Beispiel anwenden. Weitere Informationen finden Sie in der Referenzdokumentation zur Pub/Sub Java API.


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 CreateTopicWithSchemaRevisionsExample {

  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;
    // Set the minimum and maximum revsion ID
    String firstRevisionId = "your-revision-id";
    String lastRevisionId = "your-revision-id";

    createTopicWithSchemaRevisionsExample(
        projectId, topicId, schemaId, firstRevisionId, lastRevisionId, encoding);
  }

  public static void createTopicWithSchemaRevisionsExample(
      String projectId,
      String topicId,
      String schemaId,
      String firstRevisionid,
      String lastRevisionId,
      Encoding encoding)
      throws IOException {
    TopicName topicName = TopicName.of(projectId, topicId);
    SchemaName schemaName = SchemaName.of(projectId, schemaId);

    SchemaSettings schemaSettings =
        SchemaSettings.newBuilder()
            .setSchema(schemaName.toString())
            .setFirstRevisionId(firstRevisionid)
            .setLastRevisionId(lastRevisionId)
            .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

/**
 * 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';
// 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 createTopicWithSchemaRevisions(
  topicNameOrId,
  schemaNameOrId,
  encodingType,
  firstRevisionId,
  lastRevisionId
) {
  // 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,
      firstRevisionId,
      lastRevisionId,
    },
  });
  console.log(`Topic ${topicNameOrId} created with schema ${fullName}.`);
}

Node.js

/**
 * 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';
// const firstRevisionId = 'YOUR_REVISION_ID';
// const lastRevisionId = 'YOUR_REVISION_ID';

// 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 createTopicWithSchemaRevisions(
  topicNameOrId: string,
  schemaNameOrId: string,
  encodingType: 'BINARY' | 'JSON',
  firstRevisionId: string,
  lastRevisionId: string
) {
  // 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,
      firstRevisionId,
      lastRevisionId,
    },
  });
  console.log(`Topic ${topicNameOrId} created with schema ${fullName}.`);
}

PHP

Bevor Sie dieses Beispiel ausprobieren, folgen Sie der Einrichtungsanleitung für PHP in der Pub/Sub-Schnellstart mit Clientbibliotheken. Weitere Informationen finden Sie in der Referenzdokumentation zur Pub/Sub PHP API.

use Google\Cloud\PubSub\PubSubClient;
use Google\Cloud\PubSub\Schema;

/**
 * Create a topic with schema revisions.
 *
 * @param string $projectId Your Google Cloud Project ID.
 * @param string $topicId Topic ID for the new topic.
 * @param string $schemaId Existing schema id
 * @param string $firstRevisionId Minimum revision Id
 * @param string $lastRevisionId Maximum revision Id
 * @param string $encoding Either BINARY or JSON
 */
function create_topic_with_schema_revisions(
    string $projectId,
    string $topicId,
    string $schemaId,
    string $firstRevisionId,
    string $lastRevisionId,
    string $encoding
) {
    $pubsub = new PubSubClient([
        'projectId' => $projectId,
    ]);

    $schema = $pubsub->schema($schemaId);

    $topic = $pubsub->createTopic($topicId, [
        'schemaSettings' => [
            'schema' => $schema,
            'encoding' => $encoding,
            'firstRevisionId' => $firstRevisionId,
            'lastRevisionId' => $lastRevisionId,
        ]
    ]);

    printf('Topic %s created', $topic->name());
}

Python

Bevor Sie dieses Beispiel ausprobieren, folgen Sie der Einrichtungsanleitung für Python in der Pub/Sub-Schnellstart mit Clientbibliotheken. Weitere Informationen finden Sie in der Pub/Sub Python API Referenzdokumentation.

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"
# first_revision_id = "your-revision-id"
# last_revision_id = "your-revision-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,
                "first_revision_id": first_revision_id,
                "last_revision_id": last_revision_id,
            },
        }
    )
    print(f"Created a topic:\n{response}")

except AlreadyExists:
    print(f"{topic_id} already exists.")
except InvalidArgument:
    print("Please choose either BINARY or JSON as a valid message encoding type.")

Nächste Schritte

Informationen zum Suchen und Filtern von Codebeispielen für andere Google Cloud-Produkte finden Sie im Google Cloud-Beispielbrowser.