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