如果TCPServer在另一个线程中运行,Python 2不处理信号

在使用标准库时,我发现python2和python3之间存在一些奇怪的区别.如果我尝试在python2中捕获信号,而Tcpserver在不同的线程中运行,则信号不会被处理,但在python3中它确实如此.

这是一个重现问题的脚本

import signal
import threading
import sys 
if sys.version_info > (3,0):
    from socketserver import Tcpserver,BaseRequestHandler
else:
    from SocketServer import Tcpserver,BaseRequestHandler

def shutdown(signum,frame):
    print("Shutting down server thread")
    server.shutdown()

server = Tcpserver(
    ('127.0.0.1',7654),BaseRequestHandler
)
signal.signal(signal.SIGTERM,shutdown)
signal.signal(signal.SIGINT,shutdown)
server_thread = threading.Thread(target=server.serve_forever)
print("Starting server thread")
server_thread.start()
print("Waiting for server thread to shut down")
server_thread.join()
print("Server thread terminated")

这是python3的输出：

Starting server thread
Waiting for server thread to shut down
^CShutting down server thread
Server thread terminated

这是来自python2：

Starting server thread
Waiting for server thread to shut down
^CKilled

“^ C”是键盘中断,“Killed”是我发送给进程的sigkill.

为什么没有调用关机？

最佳答案

对我来说似乎thread.join()会产生一些锁定并阻止捕获信号.

我在Python 2.7中测试了以下代码,它似乎工作：

import time
import signal
import threading
import sys 
if sys.version_info > (3,frame):
    print("Shutting down server thread")
    server.running = False
    server.shutdown()

server = Tcpserver(
    ('127.0.0.1',shutdown)
server_thread = threading.Thread(target=server.serve_forever)
print("Starting server thread")
server_thread.start()
server.running = True
print("Waiting for server thread to shut down")

while server.running:
    time.sleep(1)

server_thread.join()
print("Server thread terminated")