mirror of
https://github.com/avatao-content/baseimage-tutorial-framework
synced 2024-11-05 23:31:20 +00:00
89 lines
2.6 KiB
Python
89 lines
2.6 KiB
Python
# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
|
|
# All Rights Reserved. See LICENSE file for details.
|
|
|
|
from collections import defaultdict
|
|
|
|
from tfw import BroadcastingEventHandler
|
|
from tfw.config.logs import logging
|
|
|
|
LOG = logging.getLogger(__name__)
|
|
|
|
|
|
class FSMManagingEventHandler(BroadcastingEventHandler):
|
|
def __init__(self, key, fsm_type):
|
|
super().__init__(key)
|
|
self.fsm = fsm_type()
|
|
self.fsm_manager = FSMManager(self.fsm)
|
|
self._fsm_updater = FSMUpdater(self.fsm)
|
|
|
|
self.command_handlers = {
|
|
'trigger': self.handle_trigger,
|
|
'update': self.handle_update
|
|
}
|
|
|
|
def handle_event(self, message):
|
|
try:
|
|
data = message['data']
|
|
message['data'] = self.command_handlers[data['command']](data)
|
|
return message
|
|
except KeyError:
|
|
LOG.error('IGNORING MESSAGE: Invalid message received: %s', message)
|
|
|
|
def handle_trigger(self, data):
|
|
self.fsm_manager.trigger(data['value'])
|
|
return self.with_fsm_update(data)
|
|
|
|
def with_fsm_update(self, data):
|
|
return {
|
|
**data,
|
|
**self._fsm_updater.get_fsm_state_and_transitions()
|
|
}
|
|
|
|
def handle_update(self, data):
|
|
return self.with_fsm_update(data)
|
|
|
|
|
|
class FSMManager:
|
|
def __init__(self, fsm):
|
|
self.fsm = fsm
|
|
self.trigger_predicates = defaultdict(list)
|
|
|
|
def trigger(self, trigger):
|
|
predicate_results = [
|
|
predicate()
|
|
for predicate in self.trigger_predicates[trigger]
|
|
]
|
|
|
|
# TODO: think about what could we do when this prevents triggering
|
|
if all(predicate_results):
|
|
try:
|
|
self.fsm.trigger(trigger)
|
|
except AttributeError:
|
|
LOG.debug('FSM failed to execute nonexistent trigger: "%s"', trigger)
|
|
|
|
def subscribe_predicate(self, trigger, *predicates):
|
|
self.trigger_predicates[trigger].extend(predicates)
|
|
|
|
def unsubscribe_predicate(self, trigger, *predicates):
|
|
self.trigger_predicates[trigger] = [
|
|
predicate
|
|
for predicate in self.trigger_predicates[trigger]
|
|
not in predicates
|
|
]
|
|
|
|
|
|
class FSMUpdater:
|
|
def __init__(self, fsm):
|
|
self.fsm = fsm
|
|
|
|
def get_fsm_state_and_transitions(self):
|
|
state = self.fsm.state
|
|
valid_transitions = [
|
|
{'trigger': trigger}
|
|
for trigger in self.fsm.machine.get_triggers(self.fsm.state)
|
|
]
|
|
return {
|
|
'current_state': state,
|
|
'valid_transitions': valid_transitions
|
|
}
|