Python SimPy - 请求资源一段时间，如果没有给出则退出

Question

所以基本上，要请求资源并且在等待时，如果 X 秒内没有资源给予请求，我们基本上什么都不做。“客户没有得到帮助”等。

来自他们的示例代码：

print('%s arrives at the carwash at %.2f.' % (name, env.now))
with cw.machine.request() as request:
    yield request

所以.. 当它请求 cw.machine.request() 时，只在删除请求之前执行一定的持续时间，例如不做任何事情。

print('%s arrives at the carwash at %.2f.' % (name, env.now))
with cw.machine.request() as request:
    waiting for X seconds before exiting... is it a continous loop or how does it work?

    yield request

Answer 1

我认为您的示例是 simpy 示例的一部分。要在进程（事件）之间实现条件，可以使用：

& 和 | 运算符 ---> 示例：yield first_process & second_process

和

AnyOf() AllOf() 在 simpy.events 命名空间中提供 ---> 示例：yield AnyOf(env, list_of_events)

关于一次等待多个事件的更多信息：READ THIS

此外，您可以中断另一个进程，捕获中断异常，并在进程中断时做任何您想做的事情。 READ THIS

我尝试按照您要求的方式完成资源请求：

with self.machine.request() as request:
    print(f"{car.name} requested machine at {self.env.now}")
    # waiting_threshold for 45 time
    waiting_threshold = self.env.timeout(45)

    # yield request or waiting_threshold, whichever happens earlier
    yield request | waiting_threshold

    # if (didn't get the resource) or waiting_threshold is triggered:
    if not request.triggered:
        # Interrupt washing process
        print(f"{car.name} has waited enough. Leaving carwash at {self.env.now}.")
    else:
        print(f"{car.name} started to be washed at {self.env.now}")
        # washing time 30
        yield self.env.timeout(30)
        print(f"{car.name} finished to be washed at {self.env.now}")