How to autorun migrations in sqlalchemy 2.0?

[jtpavlock]

Previously, I used the following code so a user's databases (local sqlite) could be automatically upgraded when a new migration is present.

# Config object in my_app,py

def _init_db(self, create_tables: bool = True):
    """Initializes the database.

    Args:
        create_tables: Whether or not to create and update the db tables.
            If doing db migrations manually, e.g. in alembic, this should be False.
    """
    db_path = self.config_dir / "library.db"

    if not self.engine:
        self.engine = create_engine("sqlite:///" + str(db_path))

    session_factory.configure(bind=self.engine)

    # create and update database tables
    if create_tables:
        config_path = Path(__file__)
        alembic_cfg = alembic.config.Config(
            str(config_path.parents[1] / "alembic" / "alembic.ini")
        )
        alembic_cfg.attributes["configure_logger"] = False
        with self.engine.begin() as connection:
            alembic_cfg.attributes["connection"] = connection
            alembic.command.upgrade(alembic_cfg, "head")

# env.py
def run_migrations_online():
    """Run migrations in 'online' mode.

    In this scenario we need to create an Engine and associate a connection
    with the context.
    """
    connectable = config.attributes.get("connection", None)
    if not connectable:
        # only create Engine if we don't have a Connection from the outside
        moe_config = Config(init_db=False)
        moe_config._init_db(create_tables=False)
        connectable = moe_config.engine

    # When connectable is already a Connection object, calling
    # connect() gives us a *branched connection*.
    with connectable.connect() as connection:
        context.configure(
            connection=connection, target_metadata=target_metadata, render_as_batch=True
        )

        with context.begin_transaction():
            context.run_migrations()

run_migrations_online()

But this used "connection branching" which was allowed in 1.4, but has since been deprecated. I'm failing to find an equivalent way of achieving what I want in 2.0, do you have any suggestions?

[zzzeek]

yes take a look at the modern example for connection sharing which was modified some time ago to no longer use the deprecated "branch" pattern.

[jtpavlock]

Perfect, thanks for pointing me in the right direction.