Occasionally hangs in ssl do_handshake()

[ojensen5115]

I've been experiencing a lot of "hangs" recently, where the server simply stops responding to anything. I set my code to dump the stack on SIGINT I get the following:

File: "chat.py", line 856, in <module>
  server.serveforever()
File: "SimpleWebSocketServer/SimpleWebSocketServer.py", line 609, in serveforever
  super(SimpleSSLWebSocketServer, self).serveforever()
File: "SimpleWebSocketServer/SimpleWebSocketServer.py", line 530, in serveforever
  newsock = self.decorateSocket(sock)
File: "SimpleWebSocketServer/SimpleWebSocketServer.py", line 600, in decorateSocket
  ssl_version=self.version)
File: "/usr/lib/python2.7/ssl.py", line 381, in wrap_socket
  ciphers=ciphers)
File: "/usr/lib/python2.7/ssl.py", line 143, in __init__
  self.do_handshake()
File: "/usr/lib/python2.7/ssl.py", line 305, in do_handshake
  self._sslobj.do_handshake()
File: "chat.py", line 845, in close_sig_handler
  for filename, lineno, name, line in traceback.extract_stack(stack):

Looking around Google, it seems that a number of people (particularly on Debian and using OpenSSL, which is my setup) are experiencing occasional hangs in ssl.py's do_handshake() so this isn't really a SimpleWebSocketServer issue. However, the only solution I've found so far is to modify SimpleWebSocketServer.py to set a timeout on the decorateSocket() call, using something akin to what is suggested here: http://stackoverflow.com/a/2282656/146587

[dpallot]

Ok so it appears its taking too long to complete and not timing out. I'll look at a fix.

[dpallot]

Very hard to reproduce.

[ojensen5115]

It is. I solved it in my system with the following:

timeout.py

from functools import wraps
import errno
import os
import signal

class TimeoutError(Exception):
    pass

def timeout(seconds=10, error_message=os.strerror(errno.ETIME)):
    def decorator(func):
        def _handle_timeout(signum, frame):
            raise TimeoutError(error_message)

        def wrapper(*args, **kwargs):
            signal.signal(signal.SIGALRM, _handle_timeout)
            signal.alarm(seconds)
            try:
                result = func(*args, **kwargs)
            finally:
                signal.alarm(0)
            return result

        return wraps(func)(wrapper)

    return decorator

and then throwing a "@timeout(5)" decorator on the decorateSocket function in SimpleWebServerSocket.py. From what I understand this isn't platform independent though.

[dpallot]

Ok glad you solved it for your system. I will have a look and see if this can be merged and if its a good idea. Thanks.