Enable Multithreading about python-statemachine

[svenwanzenried]

I would be interested in the also.
Currently I am thinking that I would run the whole state machine in a separate thread, and that I have to queue the incoming event myself?

[fgmacedo]

The best approach depends on the demand. Since we don't have an internal loop that "run forever", one can implement that method that reads from a stream of events and send the events to the state machine, and this method can live in a dedicated thread.

Do you have a problem idea so I can work on an example?

[fgmacedo]

We've improved the support for threading with a mutex that does multi-threading synchronization on 2.3.2 (not released yet), but basic threading (run on another thread) is possible even on older versions.

Please take a look at tests/test_threading.py for a few examples.

python-statemachine/tests/test_threading.py

Lines 78 to 127 in d446d99

	def test_regression_443_with_modifications():
	"""
	Test for https://github.com/fgmacedo/python-statemachine/issues/443
	"""
	time_collecting = 0.2
	time_to_send = 0.125
	time_sampling_current_state = 0.05
	class TrafficLightMachine(StateMachine):
	"A traffic light machine"
	green = State(initial=True)
	yellow = State()
	red = State()
	cycle = green.to(yellow) | yellow.to(red) | red.to(green)
	def __init__(self, name):
	self.name = name
	self.statuses_history = []
	super().__init__()
	def beat(self):
	waiting_time = 0
	sent = False
	while waiting_time < time_collecting:
	if waiting_time >= time_to_send and not sent:
	self.cycle()
	sent = True
	self.statuses_history.append(f"{self.name}.{self.current_state.id}")
	time.sleep(time_sampling_current_state)
	waiting_time += time_sampling_current_state
	class Controller:
	def __init__(self, name):
	self.fsm = TrafficLightMachine(name)
	# set up thread
	t = threading.Thread(target=self.fsm.beat)
	t.start()
	c1 = Controller("c1")
	c2 = Controller("c2")
	c3 = Controller("c3")
	time.sleep(time_collecting + 0.01)
	assert c1.fsm.statuses_history == ["c1.green", "c1.green", "c1.green", "c1.yellow"]
	assert c2.fsm.statuses_history == ["c2.green", "c2.green", "c2.green", "c2.yellow"]
	assert c3.fsm.statuses_history == ["c3.green", "c3.green", "c3.green", "c3.yellow"]