Connect using IAM database authentication

This snippet creates a SQLAlchemy connection pool that uses the AlloyDB Connector to connect to a database. It demonstrates how to enable IAM database authentication, allowing for secure, password-less connections.

Code sample

Python

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

import sqlalchemy

from google.cloud.alloydbconnector import Connector


def create_sqlalchemy_engine(
    inst_uri: str, user: str, db: str, refresh_strategy: str = "background"
) -> tuple[sqlalchemy.engine.Engine, Connector]:
    """Creates a connection pool for an AlloyDB instance and returns the pool
    and the connector. Callers are responsible for closing the pool and the
    connector.

    A sample invocation looks like:

        engine, connector = create_sqlalchemy_engine(
            inst_uri,
            user,
            db,
        )
        with engine.connect() as conn:
            time = conn.execute(sqlalchemy.text("SELECT NOW()")).fetchone()
            conn.commit()
            curr_time = time[0]
            # do something with query result
            connector.close()

    Args:
        instance_uri (str):
            The instance URI specifies the instance relative to the project,
            region, and cluster. For example:
            "projects/my-project/locations/us-central1/clusters/my-cluster/instances/my-instance"
        user (str):
            The formatted IAM database username.
            e.g., [e-mail], [e-mail]
        db (str):
            The name of the database, e.g., mydb
        refresh_strategy (Optional[str]):
            Refresh strategy for the AlloyDB Connector. Can be one of "lazy"
            or "background". For serverless environments use "lazy" to avoid
            errors resulting from CPU being throttled.
    """
    connector = Connector(refresh_strategy=refresh_strategy)

    # create SQLAlchemy connection pool
    engine = sqlalchemy.create_engine(
        "postgresql+psycopg://",
        creator=lambda: connector.connect(
            inst_uri,
            "psycopg",
            user=user,
            db=db,
            enable_iam_auth=True,
        ),
    )
    return engine, connector

What's next

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