SQLAlchemy engine configuration is not passed to FAB based UI. Faced this issue when running Airflow with MySQL metadata store with wait_timeout = 120. Webserver is failing with Internal Server Error due to "[MySQL Server has gone away](https://docs.sqlalchemy.org/en/13/faq/connections.html#mysql-server-has-gone-away)" error. Settings like `sql_alchemy_pool_recycle` and  `sql_alchemy_pool_pre_ping` have no impact on FAB internal communication with MySQL.

**Apache Airflow version**: 1.10.12
airflow/settings.py
"""Validate ORM Session"""
    worker_precheck = conf.getboolean('core', 'worker_precheck', fallback=False)
    if not worker_precheck:
        return True
    else:
        check_session = sessionmaker(bind=engine)
        session = check_session()
        try:
            session.execute("select 1")  # pylint
            conn_status = True
        except exc.DBAPIError as err:
            log.error(err)
            conn_status = False
        session.close()  # pylint
        return conn_status
def configure_action_logging():
    """
    Any additional configuration (register callback) for airflow.utils.action_loggers
    module
    :rtype: None
    """
def prepare_syspath():