advanced-python-homework-2023/scada_system/noblocking_turtle_shell.py

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import cmd
import threading
from queue import Queue
from equipment.turtle_device import TurtleDevice
class TurtleDeviceThread(threading.Thread):
def __init__(self):
super().__init__()
self.device = TurtleDevice()
self.queue = Queue()
self.device.open()
def add_task(self, action: str, *args, **kwargs):
self.queue.put((action, args, kwargs))
def run(self):
while True:
action, args, kwargs = self.queue.get()
if action == "stop":
self.queue.task_done()
break
self.device.execute(action, *args, **kwargs)
self.queue.task_done()
class NoBlockingTurtleShell(cmd.Cmd):
intro = 'Welcome to the turtle shell. Type help or ? to list commands.\n'
prompt = '(turtle) '
file = None
def __init__(self, turtle_thread: TurtleDeviceThread):
super().__init__()
self.turtle_thread = turtle_thread
def do_execute(self, arg):
'Executes a command with the given arguments: EXECUTE forward 100'
command_and_args = parse(arg)
if len(command_and_args) == 1:
self.turtle_thread.add_task(command_and_args[0])
return None
self.turtle_thread.add_task(command_and_args[0], *command_and_args[1:])
def do_exit(self, arg):
'Stops the message processing thread: EXIT'
print('The message processing thread has stopped.')
self.turtle_thread.add_task('stop')
return True
def parse(arg):
'Convert a series of zero or more numbers to an argument tuple'
def perform_elem(elem: str):
return int(elem) if elem.isdecimal() else elem
return tuple(map(perform_elem, arg.split()))
if __name__ == '__main__':
turtle_thread = TurtleDeviceThread()
turtle_thread.daemon = True
thread_shell = threading.Thread(target=NoBlockingTurtleShell(turtle_thread).cmdloop)
thread_shell.start()
turtle_thread.run()
thread_shell.join()