Connect using the Cloud SQL Auth Proxy

This page describes how to connect to your Cloud SQL instance using the Cloud SQL Auth Proxy.

For more information about how the Cloud SQL Auth Proxy works, see About the Cloud SQL Auth Proxy.

Overview

Using the Cloud SQL Auth Proxy is the recommended method for connecting to a Cloud SQL instance. The Cloud SQL Auth Proxy:

• Works with both public and private IP endpoints
• Validates connections using credentials for a user or service account
• Wraps the connection in a SSL/TLS layer that's authorized for a Cloud SQL instance

Some Google Cloud services and applications use the Cloud SQL Auth Proxy to provide connections for public IP paths with encryption and authorization, including:

• App Engine standard environment
• App Engine flexible environment
• Cloud Run functions
• Cloud Run

Applications running in Google Kubernetes Engine can connect using the Cloud SQL Auth Proxy.

See the Quickstart for using the Cloud SQL Auth Proxy for a basic introduction to its usage.

You can also connect, with or without the Cloud SQL Auth Proxy, using a sqlcmd client from a local machine or Compute Engine.

Before you begin

Before you can connect to a Cloud SQL instance, do the following:

1. • For a user or service account, make sure the account has the Cloud SQL Client role. This role contains the cloudsql.instances.connect permission, which authorizes a principal to connect to all Cloud SQL instances in a project.

     Go to the IAM page

   • You can optionally include an IAM condition in the IAM policy binding that grants the account permission to connect only to one specific Cloud SQL instance.

2. Enable the Cloud SQL Admin API.

   Enable the API

3. Install and initialize the gcloud CLI.
4. Optional. Install the Cloud SQL Auth Proxy Docker client.

Download the Cloud SQL Auth Proxy

docker pull gcr.io/cloud-sql-connectors/cloud-sql-proxy:2.14.0

Start the Cloud SQL Auth Proxy

You can start the Cloud SQL Auth Proxy using TCP sockets or the Cloud SQL Auth Proxy Docker image. The Cloud SQL Auth Proxy binary connects to one or more Cloud SQL instances specified on the command line, and opens a local connection as a TCP socket. Other applications and services, such as your application code or database management client tools, can connect to Cloud SQL instances through that TCP socket connection.

./cloud-sql-proxy --address 0.0.0.0 --port 1234 INSTANCE_CONNECTION_NAME

gcloud sql instances describe INSTANCE_NAME

docker run -d \\
  -v PATH_TO_KEY_FILE:/path/to/service-account-key.json \\
  -p 127.0.0.1:1433:1433 \\
  gcr.io/cloud-sql-connectors/cloud-sql-proxy:2.14.0 \\
  --address 0.0.0.0 --port 1433 \\
  --credentials-file /path/to/service-account-key.json INSTANCE_CONNECTION_NAME

docker run -d -v /cloudsql:/cloudsql \\
  -v PATH_TO_KEY_FILE:/path/to/service-account-key.json \\
  gcr.io/cloud-sql-connectors/cloud-sql-proxy:2.14.0 --unix-socket=/cloudsql \\
  --credentials-file /path/to/service-account-key.json INSTANCE_CONNECTION_NAME

-v /mnt/stateful_partition/cloudsql:/cloudsql

Connect with the sqlcmd client

The connection string you use depends on whether you started the Cloud SQL Auth Proxy using a TCP socket or Docker.

Need help? For help troubleshooting the proxy, see Troubleshooting Cloud SQL Auth Proxy connections, or see our Cloud SQL Support page.

Connect with an application

You can connect to the Cloud SQL Auth Proxy from any language that enables you to connect to a TCP socket. Below are some code snippets from complete examples on GitHub to help you understand how they work together in your application.

./cloud-sql-proxy INSTANCE_CONNECTION_NAME &

import os

import sqlalchemy


def connect_tcp_socket() -> sqlalchemy.engine.base.Engine:
    """Initializes a TCP connection pool for a Cloud SQL instance of SQL Server."""
    # Note: Saving credentials in environment variables is convenient, but not
    # secure - consider a more secure solution such as
    # Cloud Secret Manager (https://cloud.google.com/secret-manager) to help
    # keep secrets safe.
    db_host = os.environ[
        "INSTANCE_HOST"
    ]  # e.g. '127.0.0.1' ('172.17.0.1' if deployed to GAE Flex)
    db_user = os.environ["DB_USER"]  # e.g. 'my-db-user'
    db_pass = os.environ["DB_PASS"]  # e.g. 'my-db-password'
    db_name = os.environ["DB_NAME"]  # e.g. 'my-database'
    db_port = os.environ["DB_PORT"]  # e.g. 1433

    pool = sqlalchemy.create_engine(
        # Equivalent URL:
        # mssql+pytds://<db_user>:<db_pass>@<db_host>:<db_port>/<db_name>
        sqlalchemy.engine.url.URL.create(
            drivername="mssql+pytds",
            username=db_user,
            password=db_pass,
            database=db_name,
            host=db_host,
            port=db_port,
        ),
        # ...
    )

    return pool

import com.zaxxer.hikari.HikariConfig;
import com.zaxxer.hikari.HikariDataSource;
import javax.sql.DataSource;

public class TcpConnectionPoolFactory extends ConnectionPoolFactory {

  // Note: Saving credentials in environment variables is convenient, but not
  // secure - consider a more secure solution such as
  // Cloud Secret Manager (https://cloud.google.com/secret-manager) to help
  // keep secrets safe.
  private static final String DB_USER = System.getenv("DB_USER");
  private static final String DB_PASS = System.getenv("DB_PASS");
  private static final String DB_NAME = System.getenv("DB_NAME");

  private static final String INSTANCE_HOST = System.getenv("INSTANCE_HOST");
  private static final String DB_PORT = System.getenv("DB_PORT");


  public static DataSource createConnectionPool() {
    // The configuration object specifies behaviors for the connection pool.
    HikariConfig config = new HikariConfig();

    // Configure which instance and what database user to connect with.
    config.setJdbcUrl(
        String.format("jdbc:sqlserver://%s:%s;databaseName=%s", INSTANCE_HOST, DB_PORT, DB_NAME));
    config.setUsername(DB_USER); // e.g. "root", "sqlserver"
    config.setPassword(DB_PASS); // e.g. "my-password"


    // ... Specify additional connection properties here.
    // ...

    // Initialize the connection pool using the configuration object.
    return new HikariDataSource(config);
  }
}

const mssql = require('mssql');

// createTcpPool initializes a TCP connection pool for a Cloud SQL
// instance of SQL Server.
const createTcpPool = async config => {
  // Note: Saving credentials in environment variables is convenient, but not
  // secure - consider a more secure solution such as
  // Cloud Secret Manager (https://cloud.google.com/secret-manager) to help
  // keep secrets safe.
  const dbConfig = {
    server: process.env.INSTANCE_HOST, // e.g. '127.0.0.1'
    port: parseInt(process.env.DB_PORT), // e.g. 1433
    user: process.env.DB_USER, // e.g. 'my-db-user'
    password: process.env.DB_PASS, // e.g. 'my-db-password'
    database: process.env.DB_NAME, // e.g. 'my-database'
    options: {
      trustServerCertificate: true,
    },
    // ... Specify additional properties here.
    ...config,
  };
  // Establish a connection to the database.
  return mssql.connect(dbConfig);
};

package cloudsql

import (
	"database/sql"
	"fmt"
	"log"
	"os"
	"strings"

	_ "github.com/denisenkom/go-mssqldb"
)

// connectTCPSocket initializes a TCP connection pool for a Cloud SQL
// instance of SQL Server.
func connectTCPSocket() (*sql.DB, error) {
	mustGetenv := func(k string) string {
		v := os.Getenv(k)
		if v == "" {
			log.Fatalf("Fatal Error in connect_tcp.go: %s environment variable not set.\n", k)
		}
		return v
	}
	// Note: Saving credentials in environment variables is convenient, but not
	// secure - consider a more secure solution such as
	// Cloud Secret Manager (https://cloud.google.com/secret-manager) to help
	// keep secrets safe.
	var (
		dbUser    = mustGetenv("DB_USER")       // e.g. 'my-db-user'
		dbPwd     = mustGetenv("DB_PASS")       // e.g. 'my-db-password'
		dbTCPHost = mustGetenv("INSTANCE_HOST") // e.g. '127.0.0.1' ('172.17.0.1' if deployed to GAE Flex)
		dbPort    = mustGetenv("DB_PORT")       // e.g. '1433'
		dbName    = mustGetenv("DB_NAME")       // e.g. 'my-database'
	)

	dbURI := fmt.Sprintf("server=%s;user id=%s;password=%s;port=%s;database=%s;",
		dbTCPHost, dbUser, dbPwd, dbPort, dbName)


	// dbPool is the pool of database connections.
	dbPool, err := sql.Open("sqlserver", dbURI)
	if err != nil {
		return nil, fmt.Errorf("sql.Open: %w", err)
	}

	// ...

	return dbPool, nil
}

using Microsoft.Data.SqlClient;
using System;

namespace CloudSql
{
    public class SqlServerTcp
    {
        public static SqlConnectionStringBuilder NewSqlServerTCPConnectionString()
        {
            // Equivalent connection string:
            // "User Id=<DB_USER>;Password=<DB_PASS>;Server=<INSTANCE_HOST>;Database=<DB_NAME>;"
            var connectionString = new SqlConnectionStringBuilder()
            {
                // Note: Saving credentials in environment variables is convenient, but not
                // secure - consider a more secure solution such as
                // Cloud Secret Manager (https://cloud.google.com/secret-manager) to help
                // keep secrets safe.
                DataSource = Environment.GetEnvironmentVariable("INSTANCE_HOST"), // e.g. '127.0.0.1'
                // Set Host to 'cloudsql' when deploying to App Engine Flexible environment
                UserID = Environment.GetEnvironmentVariable("DB_USER"),         // e.g. 'my-db-user'
                Password = Environment.GetEnvironmentVariable("DB_PASS"),       // e.g. 'my-db-password'
                InitialCatalog = Environment.GetEnvironmentVariable("DB_NAME"), // e.g. 'my-database'

                // The Cloud SQL proxy provides encryption between the proxy and instance
                Encrypt = false,
            };
            connectionString.Pooling = true;
            // Specify additional properties here.
            return connectionString;
        }
    }
}

tcp: &tcp
  adapter: sqlserver
  # Configure additional properties here.
  # Note: Saving credentials in environment variables is convenient, but not
  # secure - consider a more secure solution such as
  # Cloud Secret Manager (https://cloud.google.com/secret-manager) to help
  # keep secrets safe.
  username: <%= ENV["DB_USER"] %>  # e.g. "my-database-user"
  password: <%= ENV["DB_PASS"] %> # e.g. "my-database-password"
  database: <%= ENV.fetch("DB_NAME") { "vote_development" } %>
  host: <%= ENV.fetch("INSTANCE_HOST") { "127.0.0.1" }%> # '172.17.0.1' if deployed to GAE Flex
  port: <%= ENV.fetch("DB_PORT") { 1433 }%> 

namespace Google\Cloud\Samples\CloudSQL\SQLServer;

use PDO;
use PDOException;
use RuntimeException;
use TypeError;

class DatabaseTcp
{
    public static function initTcpDatabaseConnection(): PDO
    {
        try {
            // Note: Saving credentials in environment variables is convenient, but not
            // secure - consider a more secure solution such as
            // Cloud Secret Manager (https://cloud.google.com/secret-manager) to help
            // keep secrets safe.
            $username = getenv('DB_USER'); // e.g. 'your_db_user'
            $password = getenv('DB_PASS'); // e.g. 'your_db_password'
            $dbName = getenv('DB_NAME'); // e.g. 'your_db_name'
            $instanceHost = getenv('INSTANCE_HOST'); // e.g. '127.0.0.1' ('172.17.0.1' for GAE Flex)

            // Connect using TCP
            $dsn = sprintf(
                'sqlsrv:server=%s;Database=%s',
                $instanceHost,
                $dbName
            );

            // Connect to the database
            $conn = new PDO(
                $dsn,
                $username,
                $password,
                # ...
            );
        } catch (TypeError $e) {
            throw new RuntimeException(
                sprintf(
                    'Invalid or missing configuration! Make sure you have set ' .
                        '$username, $password, $dbName, and $instanceHost (for TCP mode). ' .
                        'The PHP error was %s',
                    $e->getMessage()
                ),
                $e->getCode(),
                $e
            );
        } catch (PDOException $e) {
            throw new RuntimeException(
                sprintf(
                    'Could not connect to the Cloud SQL Database. Check that ' .
                        'your username and password are correct, that the Cloud SQL ' .
                        'proxy is running, and that the database exists and is ready ' .
                        'for use. For more assistance, refer to %s. The PDO error was %s',
                    'https://cloud.google.com/sql/docs/sqlserver/connect-external-app',
                    $e->getMessage()
                ),
                (int) $e->getCode(),
                $e
            );
        }

        return $conn;
    }
}

Additional topics

Cloud SQL Auth Proxy command-line arguments

The examples above cover the most common use cases, but the Cloud SQL Auth Proxy also has other configuration options that can be set with command-line arguments. For help on command-line arguments, use the --help flag to view the latest documentation:

./cloud-sql-proxy --help

See the README on the Cloud SQL Auth Proxy GitHub repository for additional examples of how to use Cloud SQL Auth Proxy command-line options.

Options for authenticating the Cloud SQL Auth Proxy

All of these options use an INSTANCE_CONNECTION_NAME as the connection string to identify a Cloud SQL instance. You can find the INSTANCE_CONNECTION_NAME on the Overview page for your instance in the Google Cloud console. or by running the following command:

gcloud sql instances describe --project PROJECT_ID INSTANCE_CONNECTION_NAME.

For example: gcloud sql instances describe --project myproject myinstance .

Some of these options use a JSON credentials file that includes the RSA private key for the account. For instructions on creating a JSON credentials file for a service account, see Creating a service account.

The Cloud SQL Auth Proxy provides several alternatives for authentication, depending on your environment. The Cloud SQL Auth Proxy checks for each of the following items, in the following order, using the first one it finds to attempt to authenticate:

1. Credentials supplied by the credentials-file flag.

   Use a service account to create and download the associated JSON file, and set the --credentials-file flag to the path of the file when you start the Cloud SQL Auth Proxy. The service account must have the required permissions for the Cloud SQL instance.

   To use this option on the command-line, invoke the cloud-sql-proxy command with the --credentials-file flag set to the path and filename of a JSON credential file. The path can be absolute, or relative to the current working directory. For example:

   ./cloud-sql-proxy --credentials-file PATH_TO_KEY_FILE \
   INSTANCE_CONNECTION_NAME
     

   For detailed instructions about adding IAM roles to a service account, see Granting Roles to Service Accounts.

   For more information about the roles Cloud SQL supports, see IAM roles for Cloud SQL.

2. Credentials supplied by an access token.

   Create an access token and invoke the cloud-sql-proxy command with the --token flag set to an OAuth 2.0 access token. For example:

   ./cloud-sql-proxy --token ACCESS_TOKEN \
   INSTANCE_CONNECTION_NAME
     

3. Credentials supplied by an environment variable.

   This option is similar to using the --credentials-file flag, except you specify the JSON credential file you set in the GOOGLE_APPLICATION_CREDENTIALS environment variable instead of using the --credentials-file command-line argument.

4. Credentials from an authenticated gcloud CLI client.

   If you have installed the gcloud CLI and have authenticated with your personal account, the Cloud SQL Auth Proxy can use the same account credentials. This method is especially helpful for getting a development environment up and running.

   To enable the Cloud SQL Auth Proxy to use your gcloud CLI credentials, use the following command to authenticate the gcloud CLI:

   gcloud auth application-default login

5. Credentials associated with the Compute Engine instance.

   If you are connecting to Cloud SQL from a Compute Engine instance, the Cloud SQL Auth Proxy can use the service account associated with the Compute Engine instance. If the service account has the required permissions for the Cloud SQL instance, the Cloud SQL Auth Proxy authenticates successfully.

   If the Compute Engine instance is in the same project as the Cloud SQL instance, the default service account for the Compute Engine instance has the necessary permissions for authenticating the Cloud SQL Auth Proxy. If the two instances are in different projects, you must add the Compute Engine instance's service account to the project containing the Cloud SQL instance.

6. Environment's default service account

   If the Cloud SQL Auth Proxy cannot find credentials in any of the places covered earlier, it follows the logic documented in Setting Up Authentication for Server to Server Production Applications. Some environment (such as Compute Engine, App Engine, and others) provide a default service account that your application can use to authenticate by default. If you use a default service account, it must have the permissions outlined in roles and permissions For more information about Google Cloud's approach to authentication, see Authentication overview.

Create a service account

1. In the Google Cloud console, go to the Service accounts page.

   Go to Service accounts

2. Select the project that contains your Cloud SQL instance.
3. Click Create service account.
4. In the Service account name field, enter a descriptive name for the service account.
5. Change the Service account ID to a unique, recognizable value and then click Create and continue.
6. Click the Select a role field and select one of the following roles:
   • Cloud SQL > Cloud SQL Client
   • Cloud SQL > Cloud SQL Editor
   • Cloud SQL > Cloud SQL Admin

7. Click Done to finish creating the service account.
8. Click the action menu for your new service account and then select Manage keys.
9. Click the Add key drop-down menu and then click Create new key.
10. Confirm that the key type is JSON and then click Create.

    The private key file is downloaded to your machine. You can move it to another location. Keep the key file secure.

Use the Cloud SQL Auth Proxy with private IP

To connect to a Cloud SQL instance using private IP, the Cloud SQL Auth Proxy must be on a resource with access to the same VPC network as the instance.

The Cloud SQL Auth Proxy uses IP to establish a connection with your Cloud SQL instance. By default, the Cloud SQL Auth Proxy attempts to connect using a public IPv4 address.

If your Cloud SQL instance has only private IP or the instance has both public and private IP configured, and you want the Cloud SQL Auth Proxy to use the private IP address, then you must provide the following option when you start the Cloud SQL Auth Proxy:

--private-ip

Use the Cloud SQL Auth Proxy with instances that have Private Service Connect enabled

You can use the Cloud SQL Auth Proxy to connect to a Cloud SQL instance with Private Service Connect enabled.

The Cloud SQL Auth Proxy is a connector that provides secure access to this instance without a need for authorized networks or for configuring SSL.

To allow Cloud SQL Auth Proxy client connections, you must set up a DNS record which matches the recommended DNS name that's provided for the instance. The DNS record is a mapping between a DNS resource and a domain name.

For more information about using the Cloud SQL Auth Proxy to connect to instances with Private Service Connect enabled, see Connect using the Cloud SQL Auth Proxy.

Run the Cloud SQL Auth Proxy in a separate process

Running the Cloud SQL Auth Proxy in a separate Cloud Shell terminal process can be useful, to avoid mixing its console output with output from other programs. Use the syntax shown below to invoke the Cloud SQL Auth Proxy in a separate process.

./cloud-sql-proxy INSTANCE_CONNECTION_NAME
  --credentials-file PATH_TO_KEY_FILE &

Start-Process --filepath "cloud-sql-proxy.exe"
  --ArgumentList "
  --credentials-file PATH_TO_KEY_FILEINSTANCE_CONNECTION_NAME"

Run the Cloud SQL Auth Proxy in a Docker container

To run the Cloud SQL Auth Proxy in a Docker container, use the Cloud SQL Auth Proxy Docker image available from the Google Container Registry. You can install the Cloud SQL Auth Proxy Docker image with this gcloud command:

docker pull gcr.io/cloud-sql-connectors/cloud-sql-proxy:2.14.0

You can start the Cloud SQL Auth Proxy using either TCP sockets or Unix sockets, with the commands shown below.

    docker run -d \
      -v PATH_TO_KEY_FILE:/path/to/service-account-key.json \
      -p 127.0.0.1:1433:1433 \
      gcr.io/cloud-sql-connectors/cloud-sql-proxy:2.14.0 \
      --address 0.0.0.0 \
      --credentials-file /path/to/service-account-key.json \
      INSTANCE_CONNECTION_NAME

    docker run -d \
      -v /PATH_TO_HOST_TARGET:/PATH_TO_GUEST_TARGET \
      -v PATH_TO_KEY_FILE:/path/to/service-account-key.json \
      gcr.io/cloud-sql-connectors/cloud-sql-proxy:2.14.0 --unix-socket /cloudsql \
      --credentials-file /path/to/service-account-key.json/PATH_TO_KEY_FILE \
      INSTANCE_CONNECTION_NAME

If you are using a container optimized image, use a writeable directory in place of /cloudsql, for example:

v /mnt/stateful_partition/cloudsql:/cloudsql

If you are using the credentials provided by your Compute Engine instance, do not include the credential_file parameter and the -v PATH_TO_KEY_FILE:/path/to/service-account-key.json line.

Running the Cloud SQL Auth Proxy as a service

Running the Cloud SQL Auth Proxy as a background service is an option for local development and production workloads. In development, when you need to access your Cloud SQL instance, you can start the service in the background and stop it when you're finished.

For production workloads, the Cloud SQL Auth Proxy doesn't currently provide built-in support for running as a Windows service, but third-party service managers can be used to run it as a service. For example, you can use NSSM to configure the Cloud SQL Auth Proxy as a Windows service, and NSSM monitors the Cloud SQL Auth Proxy and restarts it automatically if it stops responding. See the NSSM documentation for more information.

Connect when SSL is required

Enforce the use of the Cloud SQL Auth Proxy

Enable the use of the Cloud SQL Auth Proxy in Cloud SQL using ConnectorEnforcement.

If you're using a Private Service Connect-enabled instance, then there's a limitation. If the instance has connector enforcement enabled, then you can't create read replicas for the instance. Similarly, if the instance has read replicas, then you can't enable connector enforcement for the instance.

    gcloud sql instances patch INSTANCE_NAME \
    --connector-enforcement REQUIRED
  

PATCH https://sqladmin.googleapis.com/v1/projects/project-id/instances/instance-id

{
  "settings": {                     
    "connectorEnforcement": "REQUIRED"    
  }                                             
}   

curl -X PATCH \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json; charset=utf-8" \
     -d @request.json \
     "https://sqladmin.googleapis.com/v1/projects/project-id/instances/instance-id"

$cred = gcloud auth print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
    -Method PATCH `
    -Headers $headers `
    -ContentType: "application/json; charset=utf-8" `
    -InFile request.json `
    -Uri "https://sqladmin.googleapis.com/v1/projects/project-id/instances/instance-id" | Select-Object -Expand Content

{
  "kind": "sql#operation",
  "targetLink": "https://sqladmin.googleapis.com/v1/projects/project-id/instances/instance-id",
  "status": "PENDING",
  "user": "user@example.com",
  "insertTime": "2020-01-16T02:32:12.281Z",
  "operationType": "UPDATE",
  "name": "operation-id",
  "targetId": "instance-id",
  "selfLink": "https://sqladmin.googleapis.com/v1/projects/project-id/operations/operation-id",
  "targetProject": "project-id"
}

PATCH https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id

{
  "settings": {
    "connectorEnforcement": "REQUIRED"
  }
}

curl -X PATCH \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json; charset=utf-8" \
     -d @request.json \
     "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id"

$cred = gcloud auth print-access-token
$headers = @{ "Authorization" = "Bearer $cred" }

Invoke-WebRequest `
    -Method PATCH `
    -Headers $headers `
    -ContentType: "application/json; charset=utf-8" `
    -InFile request.json `
    -Uri "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id" | Select-Object -Expand Content

{
  "kind": "sql#operation",
  "targetLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/instances/instance-id",
  "status": "PENDING",
  "user": "user@example.com",
  "insertTime": "2020-01-16T02:32:12.281Z",
  "operationType": "UPDATE",
  "name": "operation-id",
  "targetId": "instance-id",
  "selfLink": "https://sqladmin.googleapis.com/sql/v1beta4/projects/project-id/operations/operation-id",
  "targetProject": "project-id"
}

Tips for working with Cloud SQL Auth Proxy

Use the Cloud SQL Auth Proxy to connect to multiple instances

You can use one local Cloud SQL Auth Proxy client to connect to multiple Cloud SQL instances. The way you do this depends on whether you are using Unix sockets or TCP.

    # Start the Cloud SQL Auth Proxy to connect to two different Cloud SQL instances.
    # Give the Cloud SQL Auth Proxy a unique port on your machine to use for each Cloud SQL instance.

    ./cloud-sql-proxy "myProject:us-central1:myInstance?port=1433" \
    "myProject:us-central1:myInstance2?port=1234"

    # Connect to "myInstance" using port 1433 on your machine:
    sqlcmd -U myUser -S "127.0.0.1,1433"

    # Connect to "myInstance2" using port 1234 on your machine:
    sqlcmd -U myUser -S "127.0.0.1,1234"
  

Troubleshoot Cloud SQL Auth Proxy connections

The Cloud SQL Auth Proxy Docker image is based on a specific version of the Cloud SQL Auth Proxy. When a new version of the Cloud SQL Auth Proxy becomes available, pull the new version of the Cloud SQL Auth Proxy Docker image to keep your environment up to date. You can see the current version of the Cloud SQL Auth Proxy by checking the Cloud SQL Auth Proxy GitHub releases page.

If you are having trouble connecting to your Cloud SQL instance using the Cloud SQL Auth Proxy, here are a few things to try to find what's causing the problem.

• Verify that you're using the IP address to connect to the instance, and not the write endpoint.

• Check the Cloud SQL Auth Proxy output.

  Often, the Cloud SQL Auth Proxy output can help you determine the source of the problem and how to solve it. Pipe the output to a file, or watch the Cloud Shell terminal where you started the Cloud SQL Auth Proxy.

• If you are getting a 403 notAuthorized error, and you are using a service account to authenticate the Cloud SQL Auth Proxy, make sure the service account has the correct permissions.

  You can check the service account by searching for its ID on the IAM page. It must have the cloudsql.instances.connect permission. The Cloud SQL Admin, Client and Editor predefined roles have this permission.

• If you are connecting from App Engine and are getting a 403 notAuthorized error, check the app.yaml value cloud_sql_instances for a misspelled or incorrect instance connection name. Instance connection names are always in the format PROJECT:REGION:INSTANCE.

  Also, check that the App Engine service account (for example, $PROJECT_ID@appspot.gserviceaccount.com) has the Cloud SQL Client IAM role.

  If the App Engine service lives in one project (project A) and the database lives in another (project B), this error means the App Engine service account has not been given the Cloud SQL Client IAM role in the project with the database (project B).

• Make sure to enable the Cloud SQL Admin API.

  If it is not, you see output like Error 403: Access Not Configured in your Cloud SQL Auth Proxy logs.

• If you are including multiple instances in your instances list, make sure you are using a comma as a delimiter, with no spaces. If you are using TCP, make sure you are specifying different ports for each instance.

• If you are connecting using UNIX sockets, confirm that the sockets were created by listing the directory you provided when you started the Cloud SQL Auth Proxy.

• If you have an outbound firewall policy, make sure it allows connections to port 3307 on the target Cloud SQL instance.

• You can confirm that the Cloud SQL Auth Proxy started correctly by looking in the logs under the Operations > Logging > Logs explorer section of the Google Cloud console. A successful operation looks like the following:

  2021/06/14 15:47:56 Listening on /cloudsql/$PROJECT_ID:$REGION:$INSTANCE_NAME/1433 for $PROJECT_ID:$REGION:$INSTANCE_NAME
  2021/06/14 15:47:56 Ready for new connections
  

• Quota issues: When the Cloud SQL Admin API quota is breached, the Cloud SQL Auth Proxy starts up with the following error message:

  There was a problem when parsing a instance configuration but ignoring due
  to the configuration. Error: googleapi: Error 429: Quota exceeded for quota
  metric 'Queries' and limit 'Queries per minute per user' of service
  'sqladmin.googleapis.com' for consumer 'project_number:$PROJECT_ID.,
  rateLimitExceeded
  

  Once an application connects to the proxy, the proxy reports the following error:

  failed to refresh the ephemeral certificate for $INSTANCE_CONNECTION_NAME:
  googleapi: Error 429: Quota exceeded for quota metric 'Queries' and limit
  'Queries per minute per user' of service 'sqladmin.googleapis.com' for
  consumer 'project_number:$PROJECT_ID., rateLimitExceeded
  

  Solution: Either identify the source of the quota problem, for example, an application is misusing the connector and unnecessarily creating new connections, or contact support to request an increase to the Cloud SQL Admin API quota. If the quota error appears on startup, you must re-deploy the application to restart the proxy. If the quota error appears after startup, a re-deploy is unnecessary.

What's next

• Learn more about the Cloud SQL Auth Proxy.
• Learn more about Identity and Access Management (IAM).
• Learn more about Service Accounts.
• Learn about the two levels of access control for Cloud SQL instances.
• Create users and databases.
• Learn about connecting to your instance from your application.
• Learn about options for support.