是否有可能终止一个正在运行的线程而不设置/检查任何标志/信号/等等?
当前回答
正如@Kozyarchuk的回答中提到的,安装跟踪工作。由于这个答案不包含代码,下面是一个工作就绪的示例:
import sys, threading, time
class TraceThread(threading.Thread):
def __init__(self, *args, **keywords):
threading.Thread.__init__(self, *args, **keywords)
self.killed = False
def start(self):
self._run = self.run
self.run = self.settrace_and_run
threading.Thread.start(self)
def settrace_and_run(self):
sys.settrace(self.globaltrace)
self._run()
def globaltrace(self, frame, event, arg):
return self.localtrace if event == 'call' else None
def localtrace(self, frame, event, arg):
if self.killed and event == 'line':
raise SystemExit()
return self.localtrace
def f():
while True:
print('1')
time.sleep(2)
print('2')
time.sleep(2)
print('3')
time.sleep(2)
t = TraceThread(target=f)
t.start()
time.sleep(2.5)
t.killed = True
它在输出1和2之后停止。3不打印。
其他回答
如果您试图终止整个程序,您可以将线程设置为“守护进程”。看到 Thread.daemon
这里还有另一种方法,但代码非常干净和简单,适用于2021年的Python 3.7:
import ctypes
def kill_thread(thread):
"""
thread: a threading.Thread object
"""
thread_id = thread.ident
res = ctypes.pythonapi.PyThreadState_SetAsyncExc(thread_id, ctypes.py_object(SystemExit))
if res > 1:
ctypes.pythonapi.PyThreadState_SetAsyncExc(thread_id, 0)
print('Exception raise failure')
改编自:https://www.geeksforgeeks.org/python-different-ways-to-kill-a-thread/
Pieter Hintjens (ØMQ-project的创始人之一)表示,使用ØMQ并避免使用锁、互斥对象、事件等同步原语,是编写多线程程序最明智、最安全的方法:
http://zguide.zeromq.org/py:all#Multithreading-with-ZeroMQ
这包括告诉子线程,它应该取消它的工作。这可以通过为线程配备ØMQ-socket并轮询该套接字以获得一条表示它应该取消的消息来实现。
该链接还提供了一个使用ØMQ的多线程python代码示例。
可以通过在将退出线程的线程中安装trace来终止线程。请参阅所附的链接,了解一种可能的实现。
在Python中杀死一个线程
虽然它相当古老,但对一些人来说这可能是一个方便的解决方案:
一个扩展线程模块功能的小模块—— 允许一个线程在另一个线程的上下文中引发异常 线程。通过触发SystemExit,你最终可以杀死python线程。
import threading
import ctypes
def _async_raise(tid, excobj):
res = ctypes.pythonapi.PyThreadState_SetAsyncExc(tid, ctypes.py_object(excobj))
if res == 0:
raise ValueError("nonexistent thread id")
elif res > 1:
# """if it returns a number greater than one, you're in trouble,
# and you should call it again with exc=NULL to revert the effect"""
ctypes.pythonapi.PyThreadState_SetAsyncExc(tid, 0)
raise SystemError("PyThreadState_SetAsyncExc failed")
class Thread(threading.Thread):
def raise_exc(self, excobj):
assert self.isAlive(), "thread must be started"
for tid, tobj in threading._active.items():
if tobj is self:
_async_raise(tid, excobj)
return
# the thread was alive when we entered the loop, but was not found
# in the dict, hence it must have been already terminated. should we raise
# an exception here? silently ignore?
def terminate(self):
# must raise the SystemExit type, instead of a SystemExit() instance
# due to a bug in PyThreadState_SetAsyncExc
self.raise_exc(SystemExit)
因此,它允许“线程在另一个线程的上下文中引发异常”,通过这种方式,被终止的线程可以处理终止,而无需定期检查中止标志。
然而,根据其原始来源,这段代码有一些问题。
The exception will be raised only when executing python bytecode. If your thread calls a native/built-in blocking function, the exception will be raised only when execution returns to the python code. There is also an issue if the built-in function internally calls PyErr_Clear(), which would effectively cancel your pending exception. You can try to raise it again. Only exception types can be raised safely. Exception instances are likely to cause unexpected behavior, and are thus restricted. For example: t1.raise_exc(TypeError) and not t1.raise_exc(TypeError("blah")). IMHO it's a bug, and I reported it as one. For more info, http://mail.python.org/pipermail/python-dev/2006-August/068158.html I asked to expose this function in the built-in thread module, but since ctypes has become a standard library (as of 2.5), and this feature is not likely to be implementation-agnostic, it may be kept unexposed.
推荐文章
- 如何禁用标准错误流的日志记录?
- 用Matplotlib在Python中绘制时间
- 类中的Python装饰器
- 在Python中锁定文件
- 得到熊猫栏目的总数
- 从pandas DataFrame中删除名称包含特定字符串的列
- Mock vs MagicMock
- 如何阅读一个。xlsx文件使用熊猫库在iPython?
- 如何访问熊猫组由数据帧按键
- Pandas和NumPy+SciPy在Python中的区别是什么?
- 将列表转换为集合会改变元素的顺序
- 如何在matplotlib更新一个情节
- TypeError: ` NoneType `对象在Python中不可迭代
- 如何在Vim注释掉一个Python代码块
- python标准库中的装饰符(特别是@deprecated)