python - 如何从运行 pyzmq 的进程捕获 SIGERM、SIGINT？

Question

我正在使用 PYZMQ，似乎我无法再捕获 SIGTERM。如何优雅地处理 SIGTERM ？

下面是代码片段:

from time import sleep
from signal import signal, SIGTERM, SIGINT
from threading import Lock, Thread
try:
    import cPickle as pickle
except ImportError:
    import pickle
import zmq


zmq_poller = None

class server(Thread, object):
    def __init__(self, transport):
        self.context = zmq.Context()
        self.zmq_socket = self.context.socket(zmq.PULL)
        self.zmq_socket.setsockopt(zmq.RCVTIMEO, 2000)
        self.zmq_socket.bind(transport)
        self.keep_running = True
        Thread.__init__(self)

    def process_data(self, data):
        data = self.decode(data)

    def decode(self, data):
        return pickle.loads(data)

    def run(self):
        while self.keep_running:
            try:
                data = self.zmq_socket.recv()
                self.process_data(data)
            except zmq.error.Again:
                pass
            except zmq.error as e:
                print e

    def stop(self):
        self.keep_running = False

def handle_stop(signum=None, frame=None):
    if zmq_poller:
        zmq_poller.stop()

if __name__ == '__main__':
    signal(SIGTERM, handle_stop)
    signal(SIGINT, handle_stop)
    mc = server('ipc:///tmp/abc')
    zmq_poller = mc
    mc.setDaemon(True)
    mc.start()
    mc.join()
    sleep(100)

正如我们所见，如果我向进程发送 SIGTERM、SIGINT，则不会调用 handle_stop 信号处理程序

Answer 1

问题的原因是您的主线程被 threading.Thread.join Execution of Python signal handlers 阻塞。 :

A Python signal handler does not get executed inside the low-level (C) signal handler. Instead, the low-level signal handler sets a flag which tells the virtual machine to execute the corresponding Python signal handler at a later point(for example at the next bytecode instruction)

…

A long-running calculation implemented purely in C (such as regular expression matching on a large body of text) may run uninterrupted for an arbitrary amount of time, regardless of any signals received. The Python signal handlers will be called when the calculation finishes.

在 3.3 之前，signal 模块绝对不会公开您自己解决此问题所需的工具。因此，如果您无法升级到 3.3，解决方案是等待可中断的事件，例如 Condition 或 Event。子线程在退出之前通知该事件，主线程在加入子线程之前等待该事件。