Pub/Sub Client Libraries

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

Note: Instructions on this page apply to the Python 3 and Java 8 App Engine standard environments. To use Python 2 with App Engine Standard, see this sample. To use Java 7, see the Google API Client Library for Java.

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

Installing the client library

C#

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

The sample below uses latest version of Pub/Sub package (beta).

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.

如果您使用的是 Maven，请将以下代码添加到您的 pom.xml 文件中。如需详细了解 BOM，请参阅 Google Cloud Platform 库 BOM。

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>com.google.cloud</groupId>
      <artifactId>libraries-bom</artifactId>
      <version>8.0.0</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

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

如果您使用的是 Gradle，请将以下代码添加到您的依赖项中：

compile 'com.google.cloud:google-cloud-pubsub:1.107.0'

如果您使用的是 sbt，请将以下代码添加到您的依赖项中：

libraryDependencies += "com.google.cloud" % "google-cloud-pubsub" % "1.107.0"

如果您使用的是 IntelliJ 或 Eclipse，可通过以下 IDE 插件将客户端库添加到您的项目中：

• Cloud Code for IntelliJ
• Cloud Tools for Eclipse

上述插件还提供其他功能，例如服务帐号密钥管理。如需了解详情，请参阅各个插件相应的文档。

注意：Cloud Java 客户端库目前不支持 Android。

Node.js

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

Beta: This is a beta release of the Node.js Cloud Client Library for the Cloud Pub/Sub API. This library might be changed in backward-incompatible ways and is not subject to any SLA or deprecation policy.

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.

Cloud Console

1. 在 Cloud Console 中，转到创建服务帐号密钥页面。

   转到“创建服务帐号密钥”页面
2. 从服务帐号列表中，选择新的服务帐号。
3. 在服务帐号名称字段中，输入一个名称。

4. 从角色列表中，选择项目 > Owner。

   注意：角色字段会为您的服务帐号授予资源访问权限。您稍后可以使用 Cloud Console 查看和更改此字段。如果您开发的是正式版应用，请指定比项目 > Owner 更为精细的权限。如需了解详情，请参阅为服务帐号授予角色。
5. 点击创建。包含密钥的 JSON 文件就会下载到计算机。

命令行

您可以使用本地机器上的 Cloud SDK 或在 Cloud Shell 中运行以下命令。

1. 创建服务帐号。将 [NAME] 替换为服务帐号的名称。

   gcloud iam service-accounts create [NAME]

2. 向服务帐号授予权限。将 [PROJECT_ID] 替换为您的项目 ID。

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

   注意：角色字段会为您的服务帐号授予资源访问权限。您稍后可以使用 Cloud Console 查看和更改此字段。如果您开发的是正式版应用，请指定比项目 > Owner 更为精细的权限。如需了解详情，请参阅向服务帐号授予角色。

3. 生成密钥文件。将 [FILE_NAME] 替换为密钥文件的名称。

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

通过设置环境变量 GOOGLE_APPLICATION_CREDENTIALS 向应用代码提供身份验证凭据。 将 [PATH] 替换为包含您的服务帐号密钥的 JSON 文件的路径。此变量仅适用于当前的 Shell 会话，因此，如果您打开新的会话，请重新设置该变量。

Linux 或 macOS

export GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

例如：

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

Windows

使用 PowerShell：

$env:GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

例如：

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

使用命令提示符：

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.

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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.

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// 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.

View on GitHub Feedback

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.

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// 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
) {
  // Instantiates a client
  const pubsub = new PubSub({projectId});

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

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.

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# 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.

View on GitHub Feedback

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(topic_path)

print("Topic created: {}".format(topic))

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.

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

# Your Google Cloud Platform project ID
project_id = "YOUR_PROJECT_ID"

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

# The name for the new topic
topic_name = "my-new-topic"

# Creates the new topic
topic = pubsub.create_topic topic_name

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

Additional resources

C#

• API Reference Documentation
• Source Code
• GitHub Issue Tracker
• Stack Overflow

Go

• API Reference Documentation
• Source Code
• GitHub Issue Tracker
• Stack Overflow

Java

• API Reference Documentation
• Source Code
• GitHub Issue Tracker
• Stack Overflow

Node.js

• API Reference Documentation
• Source Code
• GitHub Issue Tracker
• Stack Overflow

PHP

• API Reference Documentation
• Source Code
• GitHub Issue Tracker
• Stack Overflow

Python

• API Reference Documentation
• Source Code
• GitHub Issue Tracker
• Stack Overflow

Ruby

• API Reference Documentation
• Source Code
• GitHub Issue Tracker
• Stack Overflow