Datastore mode Client Libraries

This page shows how to get started with the Cloud Client Libraries for the Google Cloud 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

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

Java

For more information, see Setting Up a Java Development Environment. 如果您是使用 Maven,請在 pom.xml 檔案中新增以下指令:
<dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-datastore</artifactId>
  <version>1.75.0</version>
</dependency>
如果您是使用 Gradle,請在相依元件中新增以下指令:
compile 'com.google.cloud:google-cloud-datastore:1.75.0'
如果您是使用 SBT,請在相依元件中新增以下指令:
libraryDependencies += "com.google.cloud" % "google-cloud-datastore" % "1.75.0"

如果您使用 IntelliJ 或 Eclipse,可以使用以下 IDE 外掛程式將用戶端程式庫加入專案中:

外掛程式還提供其他功能,例如服務帳戶適用的金鑰管理。詳情請參閱各外掛程式的說明文件。

Node.js

For more information, see Setting Up a Node.js Development Environment.
npm install --save @google-cloud/datastore

PHP

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 more information, see the GCP authentication documentation .

GCP 主控台

  1. 在 GCP 主控台中,前往「Create service account key」(建立服務帳戶金鑰) 頁面。

    前往「Create Service Account Key」(建立服務帳戶金鑰) 頁面
  2. 從 [Service account] (服務帳戶) 清單中選取 [New service account] (新增服務帳戶)
  3. 在 [Service account name] (服務帳戶名稱) 欄位中輸入一個名稱。
  4. 從 [Role] (角色) 清單中,選取 [Project] (專案) > [Owner] (擁有者)

    附註:「Role」(角色) 欄位會授權服務帳戶存取資源。以後您可以使用 GCP 主控台查看及變更這個欄位。如果您要開發正式版應用程式,請指定比 [Project] (專案) > [Owner] (擁有者) 更精細的權限。詳情請參閱為服務帳戶授予角色一文。
  5. 點選 [建立]。一個包含您金鑰的 JSON 檔案會下載到電腦中。

指令列

您可以使用本機電腦上的 Cloud SDK,或在 Cloud Shell 內執行下列指令。

  1. 建立服務帳戶。將 [NAME] 換成服務帳戶的名稱。

    gcloud iam service-accounts create [NAME]
  2. 向服務帳戶授予權限。用您的專案 ID 取代 [PROJECT_ID]

    gcloud projects add-iam-policy-binding [PROJECT_ID] --member "serviceAccount:[NAME]@[PROJECT_ID].iam.gserviceaccount.com" --role "roles/owner"
    附註:「Role」(角色) 欄位會授權服務帳戶存取資源。您稍後可以使用 GCP 主控台查看及變更這個欄位。如果您要開發正式版應用程式,請指定比 [Project] (專案) > [Owner] (擁有者) 更精細的權限。詳情請參閱為服務帳戶授予角色一文。
  3. 產生金鑰檔案。用金鑰檔案的名稱取代 [FILE_NAME]

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

設定環境變數 GOOGLE_APPLICATION_CREDENTIALS 來為應用程式程式碼提供驗證憑證。 將 [PATH] 改成包含您的服務帳戶金鑰的 JSON 檔案路徑,並將 [FILE_NAME] 改成檔案名稱。 此變數僅適用於您目前的殼層工作階段,所以如果您開啟新的工作階段,請再次設定變數。

Linux 或 macOS

export GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

例如:

export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/[FILE_NAME].json"

Windows

使用 PowerShell:

$env:GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

例如:

$env:GOOGLE_APPLICATION_CREDENTIALS="C:\Users\username\Downloads\[FILE_NAME].json"

使用命令提示字元:

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

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 .

// 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)
	}

	// 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 .

// 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 .

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

async function quickStart() {
  // Your Google Cloud Platform project ID
  const projectId = 'YOUR_PROJECT_ID';

  // Creates a client
  const datastore = new Datastore({
    projectId: projectId,
  });

  // 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().catch(console.error);

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 .

# 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 .

# 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('Saved {}: {}'.format(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 .

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

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

# Instantiates a client
datastore = Google::Cloud::Datastore.new project: project_id

# 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.key kind, 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']}"

Additional Resources

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 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.

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

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