"""MySQL Connector.

Manages interactions with MySQL.
"""

from contextlib import contextmanager


@contextmanager
def db_session(session):
    """Provide a transactional scope around a series of operations.
    Taken from http://docs.sqlalchemy.org/en/latest/orm/session_basics.html.
    This handles rollback and closing of session, so there is no need
    to do that throughout the code.
    Usage:
        with db_session() as session:
            session.execute(query)
    """
    try:
        yield session
        session.commit()
    except: # noqa
        session.rollback()
        raise
    finally:
        session.close()