Create a connection using the Cloud SQL Python Connector

Open a connection to Cloud SQL for PostgreSQL by using the Cloud SQL Python Connector.

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For detailed documentation that includes this code sample, see the following:

Code sample

Python

To authenticate to Cloud SQL for PostgreSQL, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

import os

from google.cloud.sql.connector import Connector, IPTypes
import pg8000

import sqlalchemy


def connect_with_connector() -> sqlalchemy.engine.base.Engine:
    """
    Initializes a connection pool for a Cloud SQL instance of Postgres.

    Uses the Cloud SQL Python Connector package.
    """
    # 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.

    instance_connection_name = os.environ[
        "INSTANCE_CONNECTION_NAME"
    ]  # e.g. 'project:region:instance'
    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'

    ip_type = IPTypes.PRIVATE if os.environ.get("PRIVATE_IP") else IPTypes.PUBLIC

    # initialize Cloud SQL Python Connector object
    connector = Connector(refresh_strategy="LAZY")

    def getconn() -> pg8000.dbapi.Connection:
        conn: pg8000.dbapi.Connection = connector.connect(
            instance_connection_name,
            "pg8000",
            user=db_user,
            password=db_pass,
            db=db_name,
            ip_type=ip_type,
        )
        return conn

    # The Cloud SQL Python Connector can be used with SQLAlchemy
    # using the 'creator' argument to 'create_engine'
    pool = sqlalchemy.create_engine(
        "postgresql+pg8000://",
        creator=getconn,
        # ...
    )
    return pool

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