71 lines
2.1 KiB
Python
71 lines
2.1 KiB
Python
import threading
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import time
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from datetime import datetime
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from enum import Enum
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from circuitbreaker import circuit
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# Default switching time in seconds
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SWITCHING_TIME = 120
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# Scale speed of switching by factor x
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SCALING = 100
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class TrafficLight:
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class Color(Enum):
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GREEN = 0
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RED = 1
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# id of traffic light
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tlid: str
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# time between switches in seconds
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switching_time: int
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# timestamp of last switch
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last_switch: datetime
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# currently lit color
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current_color: Color
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# marks if traffic light started
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running: bool = False
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# stores starting color
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_starting_color: Color
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# stores runner thread
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_t: threading.Thread
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def __init__(self,
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tlid: str,
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switching_time: int = SWITCHING_TIME,
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starting_color: Color = Color.RED):
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self.tlid = tlid
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self.switching_time = switching_time
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self._starting_color = starting_color
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def start(self):
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self.running = True
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def switcher():
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num_colors = len(self.Color)
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# set current color to the one before starting color, because switch immediately happens in loop
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# therefore it sleeps on the end of the loop and first status is immediately sent to msg broker
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self.current_color = TrafficLight.Color((self._starting_color.value - 1) % num_colors)
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while self.running:
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self.current_color = self.Color((self.current_color.value + 1) % num_colors)
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self.last_switch = datetime.now()
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self.send_status_update()
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time.sleep(self.switching_time / SCALING)
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self._t = threading.Thread(target=switcher)
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self._t.start()
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def stop(self):
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self.running = False
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@circuit(failure_threshold=10, expected_exception=ConnectionError)
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def send_status_update(self):
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# TODO inform the message broker about the current status
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print(self.tlid, self.current_color, self.last_switch)
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if __name__ == '__main__':
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tl1 = TrafficLight(tlid='tl1')
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tl1.start()
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