Datastore mode Client Libraries

This page shows how to get started with the Cloud Client Libraries for the Datastore API. Read more about the client libraries for Cloud APIs, including the older Google APIs Client Libraries, in Client Libraries Explained.

Installing the client library

C#

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

Install-Package Google.Cloud.Datastore.V1

Go

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

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

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>20.6.0</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

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

implementation platform('com.google.cloud:libraries-bom:20.6.0')

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

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-datastore" % "1.106.5-sp.1"

如果您使用的是 IntelliJ 或 Eclipse，请通过以下 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.

npm install --save @google-cloud/datastore

PHP

For more information, see Using PHP on Google Cloud.

composer require google/cloud-datastore

Python

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

pip install --upgrade google-cloud-datastore

Ruby

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

gem install google-cloud-datastore

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

创建服务帐号：

1. 在 Cloud Console 中，转到创建服务帐号页面。

   转到“创建服务帐号”
2. 选择一个项目。

3. 在服务帐号名称字段中，输入一个名称。 Cloud Console 会根据此名称填充服务帐号 ID 字段。

   在服务帐号说明字段中，输入说明。例如，Service account for quickstart。

4. 点击创建。

5. 点击选择角色字段。

   在快速访问下，点击基本，然后点击所有者。

   注意：角色字段会影响您的服务帐号可以访问项目中的哪些资源。您可以撤消这些角色或稍后授予其他角色。在生产环境中，请勿授予 Owner、Editor 或 Viewer 角色。如需了解详情，请参阅授予、更改和撤消对资源的访问权限。
6. 点击继续。

7. 点击完成以完成服务帐号的创建过程。

   不要关闭浏览器窗口。您将在下一步骤中用到它。

创建服务帐号密钥：

1. 在 Cloud Console 中，点击您创建的服务帐号的电子邮件地址。
2. 点击密钥。
3. 依次点击添加密钥和创建新密钥。
4. 点击创建。JSON 密钥文件将下载到您的计算机上。
5. 点击关闭。

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：--role 标志会影响您的服务帐号可以访问项目中的哪些资源。您可以撤消这些角色或稍后授予其他角色。在生产环境中，请勿授予 Owner、Editor 或 Viewer 角色。如需了解详情，请参阅授予、更改和撤消对资源的访问权限。

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。 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="KEY_PATH"

将 KEY_PATH 替换为包含您的服务帐号密钥的 JSON 文件的路径。

例如：

export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/service-account-file.json"

Windows

对于 PowerShell：

$env:GOOGLE_APPLICATION_CREDENTIALS="KEY_PATH"

将 KEY_PATH 替换为包含您的服务帐号密钥的 JSON 文件的路径。

例如：

$env:GOOGLE_APPLICATION_CREDENTIALS="C:\Users\username\Downloads\service-account-file.json"

对于命令提示符：

set GOOGLE_APPLICATION_CREDENTIALS=KEY_PATH

将 KEY_PATH 替换为包含您的服务帐号密钥的 JSON 文件的路径。

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 Setting Up a C# Development Environment. For more information, see the Datastore mode C# API reference documentation.

View on GitHub Feedback

using Google.Cloud.Datastore.V1;

namespace GoogleCloudSamples
{
    public class QuickStart
    {
        public static void Main(string[] args)
        {
            // Your Google Cloud Platform project ID
            string projectId = "YOUR-PROJECT-ID";

            // Instantiates a client
            DatastoreDb db = DatastoreDb.Create(projectId);

            // The kind for the new entity
            string kind = "Task";
            // The name/ID for the new entity
            string name = "sampletask1";
            KeyFactory keyFactory = db.CreateKeyFactory(kind);
            // The Cloud Datastore key for the new entity
            Key key = keyFactory.CreateKey(name);

            var task = new Entity
            {
                Key = key,
                ["description"] = "Buy milk"
            };
            using (DatastoreTransaction transaction = db.BeginTransaction())
            {
                // Saves the task
                transaction.Upsert(task);
                transaction.Commit();

                Console.WriteLine($"Saved {task.Key.Path[0].Name}: {(string)task["description"]}");
            }
        }
    }
}

Go

To use this sample, prepare your machine for Go development, and complete the Datastore mode quickstart. For more information, see the Datastore mode Go API reference documentation.

View on GitHub Feedback

// Sample datastore-quickstart fetches an entity from Google Cloud Datastore.
package main

import (
	"context"
	"fmt"
	"log"

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

type Task struct {
	Description string
}

func main() {
	ctx := context.Background()

	// Set your Google Cloud Platform project ID.
	projectID := "YOUR_PROJECT_ID"

	// Creates a client.
	client, err := datastore.NewClient(ctx, projectID)
	if err != nil {
		log.Fatalf("Failed to create client: %v", err)
	}
	defer client.Close()

	// Sets the kind for the new entity.
	kind := "Task"
	// Sets the name/ID for the new entity.
	name := "sampletask1"
	// Creates a Key instance.
	taskKey := datastore.NameKey(kind, name, nil)

	// Creates a Task instance.
	task := Task{
		Description: "Buy milk",
	}

	// Saves the new entity.
	if _, err := client.Put(ctx, taskKey, &task); err != nil {
		log.Fatalf("Failed to save task: %v", err)
	}

	fmt.Printf("Saved %v: %v\n", taskKey, task.Description)
}

Java

Before trying this sample, follow the Java setup instructions in Setting Up a Java Development Environment. For more information, see the Datastore mode Java API reference documentation.

View on GitHub Feedback

// Imports the Google Cloud client library
import com.google.cloud.datastore.Datastore;
import com.google.cloud.datastore.DatastoreOptions;
import com.google.cloud.datastore.Entity;
import com.google.cloud.datastore.Key;

public class QuickstartSample {
  public static void main(String... args) throws Exception {
    // Instantiates a client
    Datastore datastore = DatastoreOptions.getDefaultInstance().getService();

    // The kind for the new entity
    String kind = "Task";
    // The name/ID for the new entity
    String name = "sampletask1";
    // The Cloud Datastore key for the new entity
    Key taskKey = datastore.newKeyFactory().setKind(kind).newKey(name);

    // Prepares the new entity
    Entity task = Entity.newBuilder(taskKey)
        .set("description", "Buy milk")
        .build();

    // Saves the entity
    datastore.put(task);

    System.out.printf("Saved %s: %s%n", task.getKey().getName(), task.getString("description"));

    //Retrieve entity
    Entity retrieved = datastore.get(taskKey);

    System.out.printf("Retrieved %s: %s%n", taskKey.getName(), retrieved.getString("description"));

  }
}

Node.js

Before trying this sample, follow the Node.js setup instructions in Setting Up a Node.js Development Environment. For more information, see the Datastore mode Node.js API reference documentation.

View on GitHub Feedback

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

// Creates a client
const datastore = new Datastore();

async function quickstart() {
  // The kind for the new entity
  const kind = 'Task';

  // The name/ID for the new entity
  const name = 'sampletask1';

  // The Cloud Datastore key for the new entity
  const taskKey = datastore.key([kind, name]);

  // Prepares the new entity
  const task = {
    key: taskKey,
    data: {
      description: 'Buy milk',
    },
  };

  // Saves the entity
  await datastore.save(task);
  console.log(`Saved ${task.key.name}: ${task.data.description}`);
}
quickstart();

PHP

To use this sample, prepare your machine for PHP development, and complete the Datastore mode quickstart. For more information, see the Datastore mode PHP API reference documentation.

View on GitHub Feedback

# Includes the autoloader for libraries installed with composer
require __DIR__ . '/vendor/autoload.php';

# Imports the Google Cloud client library
use Google\Cloud\Datastore\DatastoreClient;

# Your Google Cloud Platform project ID
$projectId = 'YOUR_PROJECT_ID';

# Instantiates a client
$datastore = new DatastoreClient([
    'projectId' => $projectId
]);

# The kind for the new entity
$kind = 'Task';

# The name/ID for the new entity
$name = 'sampletask1';

# The Cloud Datastore key for the new entity
$taskKey = $datastore->key($kind, $name);

# Prepares the new entity
$task = $datastore->entity($taskKey, ['description' => 'Buy milk']);

# Saves the entity
$datastore->upsert($task);

echo 'Saved ' . $task->key() . ': ' . $task['description'] . PHP_EOL;

Python

Before trying this sample, follow the Python setup instructions in Setting Up a Python Development Environment. For more information, see the Datastore mode Python API reference documentation.

View on GitHub Feedback

# Imports the Google Cloud client library
from google.cloud import datastore

# Instantiates a client
datastore_client = datastore.Client()

# The kind for the new entity
kind = "Task"
# The name/ID for the new entity
name = "sampletask1"
# The Cloud Datastore key for the new entity
task_key = datastore_client.key(kind, name)

# Prepares the new entity
task = datastore.Entity(key=task_key)
task["description"] = "Buy milk"

# Saves the entity
datastore_client.put(task)

print(f"Saved {task.key.name}: {task['description']}")

Ruby

Before trying this sample, follow the Ruby setup instructions in Setting Up a Ruby Development Environment. For more information, see the Datastore mode Ruby API reference documentation.

View on GitHub Feedback

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

# Instantiate a client
datastore = Google::Cloud::Datastore.new

# The kind for the new entity
kind = "Task"
# The name/ID for the new entity
# task_name = "sampleTask"
# The Cloud Datastore key for the new entity
task_key = datastore.key kind, task_name

# Prepares the new entity
task = datastore.entity task_key do |t|
  t["description"] = "Buy milk"
end

# Saves the entity
datastore.save task

puts "Saved #{task.key.name}: #{task['description']}"
task_key = datastore.find task_key

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

Dependency on App Engine application

If you are using a Google Cloud library to access Datastore mode, your Cloud project requires an active App Engine application. Open the App Engine dashboard and confirm your Cloud project has an active App Engine app. Create an App Engine app if needed. The app must not be disabled.

Google App Engine Standard Environment Client Libraries

Integrate Firestore in Datastore mode with your App Engine Standard Environment applications by using the App Engine client libraries.

Language	Library
Go	Google App Engine SDK for Go
Java	Google App Engine SDK for Java
Python 2	Google Datastore NDB Client Library
Python 3	Google Cloud Datastore client library.

Note: For App Engine applications that are written in Python 2, the Google Datastore DB Client Library is no longer recommended; use the Google Datastore NDB Client Library instead.

Third-party Datastore API client libraries

In addition to the Google-supported client libraries listed in the tables above, a set of third-party libraries are available.

Language	Library
Java	Objectify
Java	Catatumbo
PHP	Datastore Library for PHP
Node.js	js-data-cloud-datastore