fix `zmq` module conflict

IPython/kernel/threaded.py

@@ -1,229 +1,230
 """ Defines a KernelClient that provides thread-safe sockets with async callbacks on message replies.
 """
+from __future__ import absolute_import
 import atexit
 import errno
 from threading import Thread
 import time
 
 import zmq
 # import ZMQError in top-level namespace, to avoid ugly attribute-error messages
 # during garbage collection of threads at exit:
 from zmq import ZMQError
 from zmq.eventloop import ioloop, zmqstream
 
 # Local imports
 from IPython.utils.traitlets import Type, Instance
 from IPython.kernel.channels import HBChannel
 from IPython.kernel import KernelClient
 from IPython.kernel.channels import HBChannel
 
 class ThreadedZMQSocketChannel(object):
     """A ZMQ socket invoking a callback in the ioloop"""
     session = None
     socket = None
     ioloop = None
     stream = None
     _inspect = None
 
     def __init__(self, socket, session, loop):
         """Create a channel.
 
         Parameters
         ----------
         socket : :class:`zmq.Socket`
             The ZMQ socket to use.
         session : :class:`session.Session`
             The session to use.
         loop
             A pyzmq ioloop to connect the socket to using a ZMQStream
         """
         super(ThreadedZMQSocketChannel, self).__init__()
 
         self.socket = socket
         self.session = session
         self.ioloop = loop
 
         self.stream = zmqstream.ZMQStream(self.socket, self.ioloop)
         self.stream.on_recv(self._handle_recv)
 
     _is_alive = False
     def is_alive(self):
         return self._is_alive
 
     def start(self):
         self._is_alive = True
 
     def stop(self):
         self._is_alive = False
 
     def close(self):
         if self.socket is not None:
             try:
                 self.socket.close(linger=0)
             except Exception:
                 pass
             self.socket = None
 
     def send(self, msg):
         """Queue a message to be sent from the IOLoop's thread.
 
         Parameters
         ----------
         msg : message to send
 
         This is threadsafe, as it uses IOLoop.add_callback to give the loop's
         thread control of the action.
         """
         def thread_send():
             self.session.send(self.stream, msg)
         self.ioloop.add_callback(thread_send)
 
     def _handle_recv(self, msg):
         """Callback for stream.on_recv.
 
         Unpacks message, and calls handlers with it.
         """
         ident,smsg = self.session.feed_identities(msg)
         msg = self.session.deserialize(smsg)
         # let client inspect messages
         if self._inspect:
             self._inspect(msg)
         self.call_handlers(msg)
 
     def call_handlers(self, msg):
         """This method is called in the ioloop thread when a message arrives.
 
         Subclasses should override this method to handle incoming messages.
         It is important to remember that this method is called in the thread
         so that some logic must be done to ensure that the application level
         handlers are called in the application thread.
         """
         pass
 
     def process_events(self):
         """Subclasses should override this with a method
         processing any pending GUI events.
         """
         pass
 
 
     def flush(self, timeout=1.0):
         """Immediately processes all pending messages on this channel.
 
         This is only used for the IOPub channel.
 
         Callers should use this method to ensure that :meth:`call_handlers`
         has been called for all messages that have been received on the
         0MQ SUB socket of this channel.
 
         This method is thread safe.
 
         Parameters
         ----------
         timeout : float, optional
             The maximum amount of time to spend flushing, in seconds. The
             default is one second.
         """
         # We do the IOLoop callback process twice to ensure that the IOLoop
         # gets to perform at least one full poll.
         stop_time = time.time() + timeout
         for i in range(2):
             self._flushed = False
             self.ioloop.add_callback(self._flush)
             while not self._flushed and time.time() < stop_time:
                 time.sleep(0.01)
 
     def _flush(self):
         """Callback for :method:`self.flush`."""
         self.stream.flush()
         self._flushed = True
 
 
 class IOLoopThread(Thread):
     """Run a pyzmq ioloop in a thread to send and receive messages
     """
     def __init__(self, loop):
         super(IOLoopThread, self).__init__()
         self.daemon = True
         atexit.register(self._notice_exit)
         self.ioloop = loop or ioloop.IOLoop()
 
     def _notice_exit(self):
         self._exiting = True
 
     def run(self):
         """Run my loop, ignoring EINTR events in the poller"""
         while True:
             try:
                 self.ioloop.start()
             except ZMQError as e:
                 if e.errno == errno.EINTR:
                     continue
                 else:
                     raise
             except Exception:
                 if self._exiting:
                     break
                 else:
                     raise
             else:
                 break
 
     def stop(self):
         """Stop the channel's event loop and join its thread.
 
         This calls :meth:`~threading.Thread.join` and returns when the thread
         terminates. :class:`RuntimeError` will be raised if
         :meth:`~threading.Thread.start` is called again.
         """
         if self.ioloop is not None:
             self.ioloop.stop()
         self.join()
         self.close()
 
     def close(self):
         if self.ioloop is not None:
             try:
                 self.ioloop.close(all_fds=True)
             except Exception:
                 pass
 
 
 class ThreadedKernelClient(KernelClient):
     """ A KernelClient that provides thread-safe sockets with async callbacks on message replies.
     """
 
     _ioloop = None
     @property
     def ioloop(self):
         if self._ioloop is None:
             self._ioloop = ioloop.IOLoop()
         return self._ioloop
 
     ioloop_thread = Instance(IOLoopThread)
 
     def start_channels(self, shell=True, iopub=True, stdin=True, hb=True):
         if shell:
             self.shell_channel._inspect = self._check_kernel_info_reply
 
         self.ioloop_thread = IOLoopThread(self.ioloop)
         self.ioloop_thread.start()
 
         super(ThreadedKernelClient, self).start_channels(shell, iopub, stdin, hb)
 
     def _check_kernel_info_reply(self, msg):
         """This is run in the ioloop thread when the kernel info reply is recieved
         """
         if msg['msg_type'] == 'kernel_info_reply':
             self._handle_kernel_info_reply(msg)
             self.shell_channel._inspect = None
 
     def stop_channels(self):
         super(ThreadedKernelClient, self).stop_channels()
         if self.ioloop_thread.is_alive():
             self.ioloop_thread.stop()
 
     iopub_channel_class = Type(ThreadedZMQSocketChannel)
     shell_channel_class = Type(ThreadedZMQSocketChannel)
     stdin_channel_class = Type(ThreadedZMQSocketChannel)
     hb_channel_class = Type(HBChannel)