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Guide de démarrage rapide pour la publication

Exemple de démarrage rapide pour la publication de messages dans un sujet.

En savoir plus

Pour obtenir une documentation détaillée incluant cet exemple de code, consultez la page suivante :

Guide de démarrage rapide : publier et recevoir des messages dans Pub/Sub à l'aide d'une bibliothèque cliente

Exemple de code

C++

Avant d'essayer cet exemple, suivez les instructions de configuration pour C++ du guide de démarrage rapide de Pub/Sub à l'aide de bibliothèques clientes. Pour en savoir plus, consultez la documentation de référence sur l'API Pub/Sub pour C++.

Pour vous authentifier auprès de Pub/Sub, configurez le service Identifiants par défaut de l'application. Pour en savoir plus, consultez Configurer l'authentification pour un environnement de développement local.

#include "google/cloud/pubsub/publisher.h"
#include <iostream>

int main(int argc, char* argv[]) try {
  if (argc != 3) {
    std::cerr << "Usage: " << argv[0] << " <project-id> <topic-id>\n";
    return 1;
  }

  std::string const project_id = argv[1];
  std::string const topic_id = argv[2];

  // Create a namespace alias to make the code easier to read.
  namespace pubsub = ::google::cloud::pubsub;

  auto publisher = pubsub::Publisher(
      pubsub::MakePublisherConnection(pubsub::Topic(project_id, topic_id)));
  auto id =
      publisher
          .Publish(pubsub::MessageBuilder{}.SetData("Hello World!").Build())
          .get();
  if (!id) throw std::move(id).status();
  std::cout << "Hello World published with id=" << *id << "\n";

  return 0;
} catch (google::cloud::Status const& status) {
  std::cerr << "google::cloud::Status thrown: " << status << "\n";
  return 1;
}

C#

Avant d'essayer cet exemple, suivez les instructions de configuration pour C# du guide de démarrage rapide de Pub/Sub à l'aide de bibliothèques clientes. Pour en savoir plus, consultez la documentation de référence sur l'API Pub/Sub pour C#.


using Google.Cloud.PubSub.V1;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

public class PublishMessagesAsyncSample
{
    public async Task<int> PublishMessagesAsync(string projectId, string topicId, IEnumerable<string> messageTexts)
    {
        TopicName topicName = TopicName.FromProjectTopic(projectId, topicId);
        PublisherClient publisher = await PublisherClient.CreateAsync(topicName);

        int publishedMessageCount = 0;
        var publishTasks = messageTexts.Select(async text =>
        {
            try
            {
                string message = await publisher.PublishAsync(text);
                Console.WriteLine($"Published message {message}");
                Interlocked.Increment(ref publishedMessageCount);
            }
            catch (Exception exception)
            {
                Console.WriteLine($"An error occurred when publishing message {text}: {exception.Message}");
            }
        });
        await Task.WhenAll(publishTasks);
        // PublisherClient instance should be shutdown after use.
        // The TimeSpan specifies for how long to attempt to publish locally queued messages.
        await publisher.ShutdownAsync(TimeSpan.FromSeconds(15));
        return publishedMessageCount;
    }
}

Go

Avant d'essayer cet exemple, suivez les instructions de configuration pour Go du guide de démarrage rapide de Pub/Sub à l'aide de bibliothèques clientes. Pour en savoir plus, consultez la documentation de référence sur l'API Pub/Sub pour Go.

import (
	"context"
	"fmt"
	"io"

	"cloud.google.com/go/pubsub/v2"
)

func publish(w io.Writer, projectID, topicID, msg string) error {
	// projectID := "my-project-id"
	// topicID := "my-topic"
	// msg := "Hello World"
	ctx := context.Background()
	client, err := pubsub.NewClient(ctx, projectID)
	if err != nil {
		return fmt.Errorf("pubsub: NewClient: %w", err)
	}
	defer client.Close()

	// client.Publisher can be passed a topic ID (e.g. "my-topic") or
	// a fully qualified name (e.g. "projects/my-project/topics/my-topic").
	// If a topic ID is provided, the project ID from the client is used.
	// Reuse this publisher for all publish calls to send messages in batches.
	publisher := client.Publisher(topicID)
	result := publisher.Publish(ctx, &pubsub.Message{
		Data: []byte(msg),
	})
	// Block until the result is returned and a server-generated
	// ID is returned for the published message.
	id, err := result.Get(ctx)
	if err != nil {
		return fmt.Errorf("pubsub: result.Get: %w", err)
	}
	fmt.Fprintf(w, "Published a message; msg ID: %v\n", id)
	return nil
}

Java

Avant d'essayer cet exemple, suivez les instructions de configuration pour Java du guide de démarrage rapide de Pub/Sub à l'aide de bibliothèques clientes. Pour en savoir plus, consultez la documentation de référence sur l'API Pub/Sub pour Java.


import com.google.api.core.ApiFuture;
import com.google.cloud.pubsub.v1.Publisher;
import com.google.protobuf.ByteString;
import com.google.pubsub.v1.PubsubMessage;
import com.google.pubsub.v1.TopicName;
import java.io.IOException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;

public class PublisherExample {
  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";

    publisherExample(projectId, topicId);
  }

  public static void publisherExample(String projectId, String topicId)
      throws IOException, ExecutionException, InterruptedException {
    TopicName topicName = TopicName.of(projectId, topicId);

    Publisher publisher = null;
    try {
      // Create a publisher instance with default settings bound to the topic
      publisher = Publisher.newBuilder(topicName).build();

      String message = "Hello World!";
      ByteString data = ByteString.copyFromUtf8(message);
      PubsubMessage pubsubMessage = PubsubMessage.newBuilder().setData(data).build();

      // Once published, returns a server-assigned message id (unique within the topic)
      ApiFuture<String> messageIdFuture = publisher.publish(pubsubMessage);
      String messageId = messageIdFuture.get();
      System.out.println("Published message ID: " + messageId);
    } finally {
      if (publisher != null) {
        // When finished with the publisher, shutdown to free up resources.
        publisher.shutdown();
        publisher.awaitTermination(1, TimeUnit.MINUTES);
      }
    }
  }
}

Kotlin

import com.google.api.gax.rpc.ApiException
import com.google.api.gax.rpc.NotFoundException
import com.google.cloud.pubsub.v1.Publisher
import com.google.protobuf.ByteString
import com.google.pubsub.v1.PubsubMessage
import com.google.pubsub.v1.TopicName
import java.io.IOException
import java.util.concurrent.ExecutionException
import java.util.concurrent.TimeUnit

/**
 * Publishes a UTF-8 message payload with custom attributes to a Pub/Sub topic.
 *
 * @param projectId Google Cloud project identifier (for example, "example-project-id").
 * @param topicId Target Pub/Sub topic identifier (for example, "example-topic-id").
 */
fun publishMessage(projectId: String, topicId: String) {
  val topicName = TopicName.of(projectId, topicId)
  val payloadText = "Example Pub/Sub message payload"
  val messageData = ByteString.copyFromUtf8(payloadText)
  val messageAttributes =
    mapOf("environment" to "production", "origin" to "example-kotlin-publisher")
  val pubsubMessage =
    PubsubMessage.newBuilder()
      .setData(messageData)
      .putAllAttributes(messageAttributes)
      .build()

  var publisher: Publisher? = null
  try {
    publisher = Publisher.newBuilder(topicName).build()
    println("Publishing message to topic '${topicName}'...")
    val messageIdFuture = publisher.publish(pubsubMessage)
    val messageId = messageIdFuture.get()

    println("Resource ID: $messageId")
    println("Attributes: $messageAttributes")
    println("Topic: $topicName")
  } catch (err: ExecutionException) {
    val message =
      when (val cause = err.cause) {
        is NotFoundException ->
          "error: topic '$topicId' not found in project '$projectId': ${cause.message}"
        is ApiException ->
          "error: failed to publish message to topic '$topicId' in project '$projectId': ${cause.message}"
        else ->
          "error: execution failed while publishing to topic '$topicId' in project '$projectId': ${err.message}"
      }
    System.err.println(message)
  } catch (err: InterruptedException) {
    Thread.currentThread().interrupt()
    System.err.println(
      "error: interrupted while publishing to topic '$topicId' in project '$projectId': ${err.message}"
    )
  } catch (err: IOException) {
    System.err.println(
      "error: failed to initialize Publisher for topic '$topicId' in project '$projectId': ${err.message}"
    )
  } finally {
    if (publisher != null) {
      publisher.shutdown()
      try {
        publisher.awaitTermination(1, TimeUnit.MINUTES)
      } catch (err: InterruptedException) {
        Thread.currentThread().interrupt()
      }
    }
  }
}

PHP

Avant d'essayer cet exemple, suivez les instructions de configuration pour PHP du guide de démarrage rapide de Pub/Sub à l'aide de bibliothèques clientes. Pour en savoir plus, consultez la documentation de référence sur l'API Pub/Sub pour PHP.

use Google\Cloud\PubSub\MessageBuilder;
use Google\Cloud\PubSub\PubSubClient;

/**
 * Publishes a message for a Pub/Sub topic.
 *
 * @param string $projectId  The Google project ID.
 * @param string $topicName  The Pub/Sub topic name.
 * @param string $message  The message to publish.
 */
function publish_message($projectId, $topicName, $message)
{
    $pubsub = new PubSubClient([
        'projectId' => $projectId,
    ]);

    $topic = $pubsub->topic($topicName);
    $topic->publish((new MessageBuilder)->setData($message)->build());

    print('Message published' . PHP_EOL);
}

Ruby

Avant d'essayer cet exemple, suivez les instructions de configuration pour Ruby du guide de démarrage rapide de Pub/Sub à l'aide de bibliothèques clientes. Pour en savoir plus, consultez la documentation de référence sur l'API Pub/Sub pour Ruby.

# topic_id = "your-topic-id"

pubsub = Google::Cloud::PubSub.new
publisher = pubsub.publisher topic_id

publisher.publish "This is a test message."

puts "Message published."

Rust

use google_cloud_pubsub::client::Publisher;
use google_cloud_pubsub::model::Message;

pub async fn sample(project_id: &str, topic_id: &str) -> anyhow::Result<()> {
    let topic_name = format!("projects/{project_id}/topics/{topic_id}");
    let publisher = Publisher::builder(topic_name).build().await?;

    let message = Message::new().set_data("Hello, World!");
    let message_id = publisher.publish(message).await?;

    println!("published message with ID: {message_id}");
    Ok(())
}

Étapes suivantes

Pour rechercher et filtrer des exemples de code pour d'autres produits Google Cloud , consultez l'explorateur d'exemplesGoogle Cloud .

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