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"""Blocking channels
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Useful for test suites and blocking terminal interfaces.
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"""
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#-----------------------------------------------------------------------------
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# Copyright (C) 2013 The IPython Development Team
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#
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# Distributed under the terms of the BSD License. The full license is in
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# the file COPYING.txt, distributed as part of this software.
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#-----------------------------------------------------------------------------
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#-----------------------------------------------------------------------------
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# Imports
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#-----------------------------------------------------------------------------
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try:
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from queue import Queue, Empty # Py 3
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except ImportError:
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from Queue import Queue, Empty # Py 2
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from IPython.kernel.channels import IOPubChannel, HBChannel, \
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ShellChannel, StdInChannel
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#-----------------------------------------------------------------------------
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# Blocking kernel manager
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#-----------------------------------------------------------------------------
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class BlockingChannelMixin(object):
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def __init__(self, *args, **kwds):
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super(BlockingChannelMixin, self).__init__(*args, **kwds)
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self._in_queue = Queue()
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def call_handlers(self, msg):
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self._in_queue.put(msg)
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def get_msg(self, block=True, timeout=None):
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""" Gets a message if there is one that is ready. """
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if timeout is None:
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# Queue.get(timeout=None) has stupid uninteruptible
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# behavior, so wait for a week instead
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timeout = 604800
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return self._in_queue.get(block, timeout)
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def get_msgs(self):
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""" Get all messages that are currently ready. """
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msgs = []
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while True:
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try:
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msgs.append(self.get_msg(block=False))
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except Empty:
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break
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return msgs
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def msg_ready(self):
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""" Is there a message that has been received? """
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return not self._in_queue.empty()
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class BlockingIOPubChannel(BlockingChannelMixin, IOPubChannel):
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pass
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class BlockingShellChannel(BlockingChannelMixin, ShellChannel):
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pass
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class BlockingStdInChannel(BlockingChannelMixin, StdInChannel):
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pass
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class BlockingHBChannel(HBChannel):
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# This kernel needs quicker monitoring, shorten to 1 sec.
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# less than 0.5s is unreliable, and will get occasional
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# false reports of missed beats.
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time_to_dead = 1.
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def call_handlers(self, since_last_heartbeat):
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""" Pause beating on missed heartbeat. """
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pass
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