Python多线程安全关闭：避免重写join()方法触发线程退出

import threading
import time

class Logger(threading.Thread):
    def __init__(self) -> None:
        super().__init__()
        self.shutdown = False # 用于控制线程循环的标志

    def run(self):
        while not self.shutdown:
            time.sleep(1) # 模拟耗时操作
            print("I am busy")
        self.cleanup() # 线程退出前执行清理

    def cleanup(self):
        print("cleaning up")

    # 重写join方法，使其在等待前设置关闭标志
    def join(self, timeout=None):
        self.shutdown = True # 在这里触发关闭
        return super().join(timeout=timeout) # 调用父类的join方法等待线程结束


if __name__ == "__main__":
    my_logger = Logger()
    my_logger.start()

    try:
        while True:
            time.sleep(5)
            print("Outside loop")
    except KeyboardInterrupt:
        print("\nKeyboardInterrupt detected. Shutting down logger...")
        my_logger.join() # 调用重写后的join方法，既触发关闭又等待结束
        print("Logger shut down successfully.")

import threading
import time

class WorkerThread(threading.Thread):
    def __init__(self) -> None:
        super().__init__()
        # 使用Event对象作为关闭信号，比简单的布尔值更灵活和安全
        self._shutdown_event = threading.Event() 

    def run(self):
        print(f"{self.name} started.")
        # 循环检查关闭事件，同时执行任务
        while not self._shutdown_event.is_set():
            # 模拟耗时操作，并定期检查关闭信号
            print(f"{self.name}: I am busy...")
            # wait(timeout) 会阻塞最多timeout秒，如果事件在这期间被设置，则立即返回True
            # 这样线程可以响应关闭信号，而不需要等待time.sleep()完成
            if self._shutdown_event.wait(timeout=1): 
                break # 如果事件被设置，则跳出循环
        self.cleanup()
        print(f"{self.name} finished.")

    def cleanup(self):
        print(f"{self.name}: cleaning up resources...")

    # 提供一个显式的方法来触发线程关闭
    def stop(self):
        print(f"{self.name}: received stop signal.")
        self._shutdown_event.set() # 设置事件，通知线程停止


if __name__ == "__main__":
    my_worker = WorkerThread()
    my_worker.start()

    try:
        while True:
            time.sleep(5)
            print("Main thread: Working outside loop...")
    except KeyboardInterrupt:
        print("\nKeyboardInterrupt detected. Initiating graceful shutdown...")
        my_worker.stop() # 显式地触发线程关闭
        my_worker.join() # 纯粹地等待线程结束
        print("Main thread: WorkerThread shut down successfully.")
    except Exception as e:
        print(f"Main thread: An unexpected error occurred: {e}")
        my_worker.stop()
        my_worker.join()
    finally:
        print("Main thread: Exiting.")