Cloud Spanner Client Libraries

Cloud Spanner Client Libraries

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

The Cloud Spanner client libraries mentioned on this page are supported on Compute Engine, App Engine flexible environment, Kubernetes Engine, and Cloud Functions. The Cloud Spanner client library for Java is supported on App Engine standard environment with Java 8.

If you are using App Engine standard environment with Java 7, or App Engine standard environment with Go, PHP, or Python, use the REST interface to access Cloud Spanner.

Installing the client library

C#

To install the Google.Cloud.Spanner.Data client library in Visual Studio, do the following:

  1. Right-click your solution in Visual Studio and select Manage Nuget packages for solution.

  2. Select the Include prerelease checkbox.

  3. Search for and install the package named Google.Cloud.Spanner.Data.

Go

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

Java

If you are using Maven, add this to your pom.xml file:
<dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-spanner</artifactId>
  <version>0.49.0-beta</version>
</dependency>
If you are using Gradle, add this to your dependencies:
compile 'com.google.cloud:google-cloud-spanner:0.49.0-beta'
If you are using SBT, add this to your dependencies:
libraryDependencies += "com.google.cloud" % "google-cloud-spanner" % "0.49.0-beta"

Node.js

npm install --save @google-cloud/spanner

PHP

composer require google/cloud-spanner

Python

For more on setting up your Python development environment, refer to Python Development Environment Setup Guide.
pip install --upgrade google-cloud-spanner

Ruby

gem install google-cloud-spanner

Setting up authentication

To run the client library, you must first set up authentication by creating a service account and setting an environment variable.

GCP Console

  1. Go to the Create service account key page in the GCP Console.

    Go to the Create Service Account Key page
  2. From the Service account drop-down list, select New service account.
  3. Enter a name into the Service account name field.
  4. From the Role drop-down list, select Project > Owner.

    Note: The Role field authorizes your service account to access resources. You can view and change this field later using GCP Console. If you are developing a production application, specify more granular permissions than Project > Owner. For more information, see granting roles to service accounts.
  5. Click Create. A JSON file that contains your key downloads to your computer.

Command line

You can run the following commands using the Cloud SDK on your local machine, or within Cloud Shell.

  1. Create the service account. Replace [NAME] with your desired service account name.

    gcloud iam service-accounts create [NAME]
  2. Grant permissions to the service account. Replace [PROJECT_ID] with your project ID.

    gcloud projects add-iam-policy-binding [PROJECT_ID] --member "serviceAccount:[NAME]@[PROJECT_ID].iam.gserviceaccount.com" --role "roles/owner"
    Note: The Role field authorizes your service account to access resources. You can view and change this field later using GCP Console. If you are developing a production application, specify more granular permissions than Project > Owner. For more information, see granting roles to service accounts.
  3. Generate the key file. Replace [FILE_NAME] with a name for the key file.

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

Provide authentication credentials to your application code by setting the environment variable GOOGLE_APPLICATION_CREDENTIALS. Replace [PATH] with the file path of the JSON file that contains your service account key, and [FILE_NAME] with the filename.

Linux or macOS

export GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

For example:

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

Windows

With PowerShell:

$env:GOOGLE_APPLICATION_CREDENTIALS="[PATH]"

For example:

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

With command prompt:

set GOOGLE_APPLICATION_CREDENTIALS=[PATH]

Using the client library

The following example shows how to use the client library.

C#

Read more in the C# API Reference Documentation for the Cloud Spanner API Client Library.

using Google.Cloud.Spanner.Data;
using System;
using System.Threading.Tasks;

namespace GoogleCloudSamples.Spanner
{
    public class QuickStart
    {
        static async Task MainAsync()
        {
            string projectId = "YOUR-PROJECT-ID";
            string instanceId = "my-instance";
            string databaseId = "my-database";
            string connectionString =
                $"Data Source=projects/{projectId}/instances/{instanceId}/"
                + $"databases/{databaseId}";
            // Create connection to Cloud Spanner.
            using (var connection = new SpannerConnection(connectionString))
            {
                // Execute a simple SQL statement.
                var cmd = connection.CreateSelectCommand(
                    @"SELECT ""Hello World"" as test");
                using (var reader = await cmd.ExecuteReaderAsync())
                {
                    while (await reader.ReadAsync())
                    {
                        Console.WriteLine(
                            reader.GetFieldValue<string>("test"));
                    }
                }
            }
        }
        public static void Main(string[] args)
        {
            MainAsync().Wait();
        }
    }
}

Go

Read more in the Go API Reference Documentation for the Cloud Spanner API Client Library.

// Sample spanner_quickstart is a basic program that uses Cloud Spanner.
package main

import (
	"fmt"
	"log"

	"cloud.google.com/go/spanner"
	"golang.org/x/net/context"
)

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

	// This database must exist.
	databaseName := "projects/your-project-id/instances/your-instance-id/databases/your-database-id"

	client, err := spanner.NewClient(ctx, databaseName)
	if err != nil {
		log.Fatalf("Failed to create client %v", err)
	}
	defer client.Close()

	stmt := spanner.Statement{SQL: "SELECT 1"}
	iter := client.Single().Query(ctx, stmt)
	defer iter.Stop()

	row, err := iter.Next()
	if err != nil {
		log.Fatalf("Query failed with %v", err)
	}

	var i int64
	if row.Columns(&i) != nil {
		log.Fatalf("Failed to parse row %v", err)
	}
	fmt.Printf("Got value %v\n", i)
}

Java

Read more in the Java API Reference Documentation for the Cloud Spanner API Client Library.

// Imports the Google Cloud client library
import com.google.cloud.spanner.DatabaseClient;
import com.google.cloud.spanner.DatabaseId;
import com.google.cloud.spanner.ResultSet;
import com.google.cloud.spanner.Spanner;
import com.google.cloud.spanner.SpannerOptions;
import com.google.cloud.spanner.Statement;

/**
 * A quick start code for Cloud Spanner. It demonstrates how to setup the Cloud Spanner client and
 * execute a simple query using it against an existing database.
 */
public class QuickstartSample {
  public static void main(String... args) throws Exception {

    if (args.length != 2) {
      System.err.println("Usage: QuickStartSample <instance_id> <database_id>");
      return;
    }
    // Instantiates a client
    SpannerOptions options = SpannerOptions.newBuilder().build();
    Spanner spanner = options.getService();

    // Name of your instance & database.
    String instanceId = args[0];
    String databaseId = args[1];
    try {
      // Creates a database client
      DatabaseClient dbClient = spanner.getDatabaseClient(DatabaseId.of(
          options.getProjectId(), instanceId, databaseId));
      // Queries the database
      ResultSet resultSet = dbClient.singleUse().executeQuery(Statement.of("SELECT 1"));

      System.out.println("\n\nResults:");
      // Prints the results
      while (resultSet.next()) {
        System.out.printf("%d\n\n", resultSet.getLong(0));
      }
    } finally {
      // Closes the client which will free up the resources used
      spanner.close();
    }
  }
}

Node.js

Read more in the Node.js API Reference Documentation for the Cloud Spanner API Client Library.

// Imports the Google Cloud client library
const Spanner = require('@google-cloud/spanner');

// Your Google Cloud Platform project ID
const projectId = 'YOUR_PROJECT_ID';

// Creates a client
const spanner = Spanner({
  projectId: projectId,
});

// Your Cloud Spanner instance ID
const instanceId = 'my-instance';

// Your Cloud Spanner database ID
const databaseId = 'my-database';

// Gets a reference to a Cloud Spanner instance and database
const instance = spanner.instance(instanceId);
const database = instance.database(databaseId);

// The query to execute
const query = {
  sql: 'SELECT 1',
};

// Execute a simple SQL statement
database
  .run(query)
  .then(results => {
    const rows = results[0];

    rows.forEach(row => console.log(row));
  })
  .catch(err => {
    console.error('ERROR:', err);
  });

PHP

Read more in the PHP API Reference Documentation for the Cloud Spanner API Client Library.

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

# Imports the Google Cloud client library
use Google\Cloud\Spanner\SpannerClient;

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

# Instantiates a client
$spanner = new SpannerClient([
    'projectId' => $projectId
]);

# Your Cloud Spanner instance ID.
$instanceId = 'your-instance-id';

# Get a Cloud Spanner instance by ID.
$instance = $spanner->instance($instanceId);

# Your Cloud Spanner database ID.
$databaseId = 'your-database-id';

# Get a Cloud Spanner database by ID.
$database = $instance->database($databaseId);

# Execute a simple SQL statement.
$results = $database->execute('SELECT "Hello World" as test');

foreach ($results as $row) {
    print($row['test'] . PHP_EOL);
}

Python

Read more in the Python API Reference Documentation for the Cloud Spanner API Client Library.

# Imports the Google Cloud Client Library.
from google.cloud import spanner

# Instantiate a client.
spanner_client = spanner.Client()

# Your Cloud Spanner instance ID.
instance_id = 'my-instance-id'

# Get a Cloud Spanner instance by ID.
instance = spanner_client.instance(instance_id)

# Your Cloud Spanner database ID.
database_id = 'my-database-id'

# Get a Cloud Spanner database by ID.
database = instance.database(database_id)

# Execute a simple SQL statement.
with database.snapshot() as snapshot:
    results = snapshot.execute_sql('SELECT 1')

    for row in results:
        print(row)

Ruby

Read more in the Ruby API Reference Documentation for the Cloud Spanner API Client Library.

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

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

# Instantiates a client
spanner = Google::Cloud::Spanner.new project: project_id

# Your Cloud Spanner instance ID
instance_id = "my-instance"

# Your Cloud Spanner database ID
database_id = "my-database"

# Gets a reference to a Cloud Spanner instance database
database_client = spanner.client instance_id, database_id

# Execute a simple SQL statement
database_client.transaction do |transaction|
  results = transaction.execute "SELECT 1"

  results.rows.each do |row|
    puts row
  end
end

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