Flask-SQLAlchemy has some nice built-ins (e.g. accessing query directly on classes). To continue leveraging these nicities while still inside of a Celery worker, we need to make sure we setup/teardown in a similar fashion to Flask-SQLAlchemy does on Flask.
Flask-SQLAlchemy uses create_scoped_session at startup which avoids any setup on a per-request basis.
https://github.com/mitsuhiko/flask-sqlalchemy/blob/2.0/flask_sqlalchemy/__init__.py#L668
This means Celery can piggyback off of this initialization.