Pub/Sub Client Libraries

This page shows how to get started with the Cloud Client Libraries for the Pub/Sub API.

Read more about the client libraries for Cloud APIs in Client Libraries Explained.

Installing the client library

C++

For more information about installing the C++ library, see the GitHub README.

C#

For more information, see Setting Up a C# Development Environment.

Install-Package Google.Cloud.PubSub.V1 -Pre

Go

For more information, see Setting Up a Go Development Environment.

go get -u cloud.google.com/go/pubsub

Java

For more information, see Setting Up a Java Development Environment.

Se você estiver usando o Maven, adicione o código abaixo ao arquivo pom.xml. Para mais informações sobre BOMs, consulte BOM das bibliotecas do Google Cloud Platform.

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>com.google.cloud</groupId>
      <artifactId>libraries-bom</artifactId>
      <version>16.4.0</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

<dependencies>
  <dependency>
    <groupId>com.google.cloud</groupId>
    <artifactId>google-cloud-pubsub</artifactId>
  </dependency>

Se você estiver usando o Gradle, adicione isto às dependências:

implementation platform('com.google.cloud:libraries-bom:16.4.0')

compile 'com.google.cloud:google-cloud-pubsub'

Se você estiver usando o sbt, adicione o seguinte às suas dependências:

libraryDependencies += "com.google.cloud" % "google-cloud-pubsub" % "1.111.0"

Caso você esteja usando o IntelliJ ou o Eclipse, poderá adicionar bibliotecas de cliente ao seu projeto usando estes plug-ins de ambiente de desenvolvimento integrado:

Os plug-ins também oferecem outras funcionalidades, como gerenciamento de chaves de contas de serviço. Consulte a documentação de cada plug-in para mais detalhes.

Node.js

For more information, see Setting Up a Node.js Development Environment.

npm install --save @google-cloud/pubsub

PHP

For more information, see Using PHP on Google Cloud.

composer require google/cloud-pubsub

Python

For more information, see Setting Up a Python Development Environment.

pip install --upgrade google-cloud-pubsub

Ruby

For more information, see Setting Up a Ruby Development Environment.

gem install google-cloud-pubsub

Setting up authentication

To run the client library, you must first set up authentication by creating a service account and setting an environment variable. Complete the following steps to set up authentication. For other ways to authenticate, see the GCP authentication documentation.

Console do Cloud

  1. No Console do Cloud, acesse a página Criar chave da conta de serviço.

    Acessar página "Criar chave da conta de serviço"
  2. Na lista Conta de serviço, selecione Nova conta de serviço.
  3. No campo Nome da conta de serviço, insira um nome.

  4. Na lista Papel, selecione Projeto > Proprietário.

  5. Clique em Criar. O download de um arquivo JSON que contém sua chave é feito no seu computador.

Linha de comando

É possível executar os seguintes comandos usando o SDK do Cloud na máquina local ou no Cloud Shell.

  1. Crie a conta de serviço. Substitua NAME por um nome para a conta de serviço. 

    gcloud iam service-accounts create NAME

  2. Conceda permissões à conta de serviço. Substitua PROJECT_ID pelo ID do seu projeto. 

    gcloud projects add-iam-policy-binding PROJECT_ID --member="serviceAccount:NAME@PROJECT_ID.iam.gserviceaccount.com" --role="roles/owner"

  3. Gere o arquivo de chave. Substitua FILE_NAME pelo nome do arquivo de chave. 

    gcloud iam service-accounts keys create FILE_NAME.json --iam-account=NAME@PROJECT_ID.iam.gserviceaccount.com

Forneça credenciais de autenticação ao código do aplicativo definindo a variável de ambiente GOOGLE_APPLICATION_CREDENTIALS. Substitua [PATH] pelo caminho do arquivo JSON que contém sua chave da conta de serviço. Essa variável só se aplica à sessão de shell atual. Assim, se você abrir uma nova sessão, precisará definir a variável novamente.

Linux ou macOS

export GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

Exemplo:

export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/my-key.json"

Windows

Com o PowerShell:

$env:GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

Exemplo:

$env:GOOGLE_APPLICATION_CREDENTIALS="C:\Users\username\Downloads\my-key.json"

Com prompt de comando:

set GOOGLE_APPLICATION_CREDENTIALS=[PATH]

Using the client library

The following example shows how to use the client library.

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. 

namespace pubsub = google::cloud::pubsub;
[](pubsub::TopicAdminClient client, std::string project_id,
   std::string topic_id) {
  auto topic = client.CreateTopic(pubsub::TopicBuilder(
      pubsub::Topic(std::move(project_id), std::move(topic_id))));
  // 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::runtime_error(topic.status().message());

  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. 


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

public class CreateTopicSample
{
    public Topic CreateTopic(string projectId, string topicId)
    {
        PublisherServiceApiClient publisher = PublisherServiceApiClient.Create();
        var topicName = TopicName.FromProjectTopic(projectId, topicId);
        Topic topic = null;

        try
        {
            topic = publisher.CreateTopic(topicName);
            Console.WriteLine($"Topic {topic.Name} created.");
        }
        catch (RpcException e) when (e.Status.StatusCode == StatusCode.AlreadyExists)
        {
            Console.WriteLine($"Topic {topicName} already exists.");
        }
        return topic;
    }
}

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.

If you're using the first generation of the App Engine standard runtime, we recommend using the older Google APIs Client Libraries. See this GitHub issue for more details. 

// Sample pubsub-quickstart creates a Google Cloud Pub/Sub topic.
package main

import (
	"context"
	"fmt"
	"log"

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

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)
	}

	// Sets the id for the new topic.
	topicID := "my-topic"

	// Creates the new topic.
	topic, err := client.CreateTopic(ctx, topicID)
	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. 


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());
    }
  }
}

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. 

// Imports the Google Cloud client library
const {PubSub} = require('@google-cloud/pubsub');

async function quickstart(
  projectId = 'your-project-id', // Your Google Cloud Platform project ID
  topicName = 'my-topic', // Name for the new topic to create
  subscriptionName = 'my-sub' // Name for the new subscription to create
) {
  // Instantiates a client
  const pubsub = new PubSub({projectId});

  // Creates a new topic
  const [topic] = await pubsub.createTopic(topicName);
  console.log(`Topic ${topic.name} created.`);

  // Creates a subscription on that new topic
  const [subscription] = await topic.createSubscription(subscriptionName);

  // Receive callbacks for new messages on the subscription
  subscription.on('message', message => {
    console.log('Received message:', message.data.toString());
    process.exit(0);
  });

  // Receive callbacks for errors on the subscription
  subscription.on('error', error => {
    console.error('Received error:', error);
    process.exit(1);
  });

  // Send a message to the topic
  topic.publish(Buffer.from('Test message!'));
}

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. 

# 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.';

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. 

from google.cloud import pubsub_v1

# TODO(developer)
# project_id = "your-project-id"
# topic_id = "your-topic-id"

publisher = pubsub_v1.PublisherClient()
topic_path = publisher.topic_path(project_id, topic_id)

topic = publisher.create_topic(request={"name": topic_path})

print("Created topic: {}".format(topic.name))

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. 

# Imports the Google Cloud client library
require "google/cloud/pubsub"

# Instantiates a client
pubsub = Google::Cloud::Pubsub.new

# The name for the new topic
# topic_id = "your-topic-id"

# Creates the new topic
topic = pubsub.create_topic topic_id

puts "Topic #{topic.name} created."

Additional resources