baseimage-tutorial-framework/lib/tfw/builtins/fsm_aware_event_handler.py

from tfw.components import FSMAware
from tfw.networking import Scope

from .event_handler import EventHandler


class FSMAwareEventHandler(EventHandler, FSMAware):
    # pylint: disable=abstract-method
    """
    Abstract base class for EventHandlers which automatically
    keep track of the state of the TFW FSM.
    """
    def __init__(self, key, scope=Scope.ZMQ):
        EventHandler.__init__(self, key, scope=scope)
        FSMAware.__init__(self)
        self.subscribe('fsm_update')

    def dispatch_handling(self, message):
        if not self.refresh_on_fsm_update(message):
            super().dispatch_handling(message)