I've run into strange behavior involving a blocking call to a socket accept()
on the main thread and thread.interrupt_main() being called on a worker thread.
Here's my code:
# BEGIN exception_test.py
import socket
import thread
import threading
import time
def worker():
time.sleep(2)
print 'Interrupting main'
thread.interrupt_main()
print 'main interrupted!'
sock = socket.socket()
sock.bind(('127.0.0.1', 8080))
sock.settimeout(5)
sock.listen(0)
t = threading.Thread(target=worker)
t.start()
try:
connection, _ = sock.accept()
except KeyboardInterrupt:
print 'KeyboardInterrupt!'
except socket.timeout:
print 'Socket timeout!'
print 'exiting'
# END exception_test.py
I would expect this output:
Interrupting main
main interrupted!
KeyboardInterrupt caught!
exiting
But instead, I'm seeing this:
Interrupting main
main interrupted!
Traceback (most recent call last):
File "exception_test.py", line 23, in <module>
connection, _ = sock.accept()
KeyboardInterrupt
Despite my "except KeyboardInterrupt", the KeyboardInterrupt forced by the
thread.interrupt_main() in the worker thread isn't being caught.
Other things worth noting is that the exception takes about 3 seconds after the
call to thread.interrupt_main(). It appears to not actually happen until the
sock.accept() times out. If the call to sock.settimeout(5) is removed, the
KeyboardInterrupt never appears and flow is still blocked on the sock.accept().
My Python version is 2.7.3. I know its out of date, but I don't really have a
choice.
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