Custom Connection Creators

[luciengaitskell]

With SQLAlchemy it's possible to connect to a server using a custom connection creator like so:

def getconn():
    conn = connector.connect(
        "project:region:instance",
        "pg8000",
        user="postgres-iam-user@gmail.com",
        db="my_database",
        enable_iam_auth=True,
    )

    return conn

engine = sqlalchemy.create_engine(
    "postgres+pg8000://",
    creator=getconn,
)

This enables functionality such as connecting to a Google Cloud SQL server with Automatic IAM using the cloud-sql-python-connector library (shown above). Is it possible to configure the same in Alembic?

[zzzeek]

the create_engine logic is editable within your env.py file that's local to your environment, after running "alembic init". Go in there and set up the create_engine logic that you need.

in this case the code you would be augmenting is at:

alembic/alembic/templates/generic/env.py

Lines 59 to 64 in d95e15c

	connectable = engine_from_config(
	config.get_section(config.config_ini_section),
	prefix="sqlalchemy.",
	poolclass=pool.NullPool,
	)

that is the engine object. you'd replace this with your create_engine() code above.

https://alembic.sqlalchemy.org/en/latest/tutorial.html#the-migration-environment

[luciengaitskell]

Thank you for the quick response. I was able to pass the creator argument right there.

I appreciate the help!