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
"""
    Ensures that certain subfolders of AIRFLOW_HOME are on the classpath
    """
    if DAGS_FOLDER not in sys.path:
        sys.path.append(DAGS_FOLDER)
    # Add ./config/ for loading custom log parsers etc, or
    # airflow_local_settings etc.
    config_path = os.path.join(AIRFLOW_HOME, 'config')
    if config_path not in sys.path:
        sys.path.append(config_path)
    if PLUGINS_FOLDER not in sys.path:
        sys.path.append(PLUGINS_FOLDER)
def import_local_settings():
    """Import airflow_local_settings.py files to allow overriding any configs in settings.py file"""
    try:  # pylint
        import airflow_local_settings
        if hasattr(airflow_local_settings, "__all__"):
            for i in airflow_local_settings.__all__:  # pylint
                globals()[i] = getattr(airflow_local_settings, i)
        else:
            for k, v in airflow_local_settings.__dict__.items():
                if not k.startswith("__"):
                    globals()[k] = v
        log.info("Loaded airflow_local_settings from %s .", airflow_local_settings.__file__)
    except ImportError:
        log.debug("Failed to import airflow_local_settings.", exc_info=True)
def initialize():