How to implement thread termination and suspension in Python

The content of this article is about the implementation method of thread termination and suspension in Python. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

There is no method for a thread to force terminate or suspend. This is by design because writing threaded programs is inherently complex. For example: If a thread has acquired a lock, forcing it to terminate or suspend it before it can release the lock will cause a deadlock in the entire application. In addition, termination generally cannot simply "release all locks", because complex thread synchronization often involves locking and clear locking operations, and the order of these operations must be very precise when executed.

If you want to provide services for termination or suspend, you need to build these functions yourself. A common approach is to run the thread in a loop that periodically checks the thread's status to determine whether it should terminate. For example:

from threading import  Thread,Lock
class StoppableThread(Thread):
    def __init__(self):
        Thread.__init__(self)
        self._terminate=False
        self._suspend_lock=Lock()

    def terminate(self):
        self._terminate=True

    def suspend(self):
        self._suspend_lock.acquire()

    def resume(self):
        self._suspend_lock.release()

    def run(self):
        while True:
            if self._terminate:
                break
            self._suspend_lock.acquire()
            self._suspend_lock.release()
            ...

Remember, for this method to work reliably, the thread should be extremely careful not to perform any kind of blocking I/O operation. For example, if a thread blocks waiting for data to arrive, it will not terminate until the operation is awakened. Therefore, you need to use timeouts, non-blocking I/O, and other advanced features in practice to ensure that termination checks are performed frequently enough.

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