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"""Base classes to manage the interaction with a running kernel.
TODO
* Create logger to handle debugging and console messages.
"""
#-----------------------------------------------------------------------------
# Copyright (C) 2008-2011 The IPython Development Team
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------
# Standard library imports.
import atexit
import errno
import json
from subprocess import Popen
import os
import signal
import sys
from threading import Thread
import time
# System library imports.
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.config.loader import Config
from IPython.utils.localinterfaces import LOCALHOST, LOCAL_IPS
from IPython.utils.traitlets import (
HasTraits, Any, Instance, Type, Unicode, Integer, Bool
)
from IPython.utils.py3compat import str_to_bytes
from IPython.zmq.entry_point import write_connection_file
from session import Session
#-----------------------------------------------------------------------------
# Constants and exceptions
#-----------------------------------------------------------------------------
class InvalidPortNumber(Exception):
pass
#-----------------------------------------------------------------------------
# Utility functions
#-----------------------------------------------------------------------------
# some utilities to validate message structure, these might get moved elsewhere
# if they prove to have more generic utility
def validate_string_list(lst):
"""Validate that the input is a list of strings.
Raises ValueError if not."""
if not isinstance(lst, list):
raise ValueError('input %r must be a list' % lst)
for x in lst:
if not isinstance(x, basestring):
raise ValueError('element %r in list must be a string' % x)
def validate_string_dict(dct):
"""Validate that the input is a dict with string keys and values.
Raises ValueError if not."""
for k,v in dct.iteritems():
if not isinstance(k, basestring):
raise ValueError('key %r in dict must be a string' % k)
if not isinstance(v, basestring):
raise ValueError('value %r in dict must be a string' % v)
#-----------------------------------------------------------------------------
# ZMQ Socket Channel classes
#-----------------------------------------------------------------------------
class ZMQSocketChannel(Thread):
"""The base class for the channels that use ZMQ sockets.
"""
context = None
session = None
socket = None
ioloop = None
stream = None
_address = None
_exiting = False
def __init__(self, context, session, address):
"""Create a channel
Parameters
----------
context : :class:`zmq.Context`
The ZMQ context to use.
session : :class:`session.Session`
The session to use.
address : tuple
Standard (ip, port) tuple that the kernel is listening on.
"""
super(ZMQSocketChannel, self).__init__()
self.daemon = True
self.context = context
self.session = session
if address[1] == 0:
message = 'The port number for a channel cannot be 0.'
raise InvalidPortNumber(message)
self._address = address
atexit.register(self._notice_exit)
def _notice_exit(self):
self._exiting = True
def _run_loop(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 activity.
This calls :method:`Thread.join` and returns when the thread
terminates. :class:`RuntimeError` will be raised if
:method:`self.start` is called again.
"""
self.join()
@property
def address(self):
"""Get the channel's address as an (ip, port) tuple.
By the default, the address is (localhost, 0), where 0 means a random
port.
"""
return self._address
def _queue_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)
self.call_handlers(self.session.unserialize(smsg))
class ShellSocketChannel(ZMQSocketChannel):
"""The DEALER channel for issues request/replies to the kernel.
"""
command_queue = None
# flag for whether execute requests should be allowed to call raw_input:
allow_stdin = True
def __init__(self, context, session, address):
super(ShellSocketChannel, self).__init__(context, session, address)
self.ioloop = ioloop.IOLoop()
def run(self):
"""The thread's main activity. Call start() instead."""
self.socket = self.context.socket(zmq.DEALER)
self.socket.setsockopt(zmq.IDENTITY, self.session.bsession)
self.socket.connect('tcp://%s:%i' % self.address)
self.stream = zmqstream.ZMQStream(self.socket, self.ioloop)
self.stream.on_recv(self._handle_recv)
self._run_loop()
try:
self.socket.close()
except:
pass
def stop(self):
self.ioloop.stop()
super(ShellSocketChannel, self).stop()
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 leve
handlers are called in the application thread.
"""
raise NotImplementedError('call_handlers must be defined in a subclass.')
def execute(self, code, silent=False,
user_variables=None, user_expressions=None, allow_stdin=None):
"""Execute code in the kernel.
Parameters
----------
code : str
A string of Python code.
silent : bool, optional (default False)
If set, the kernel will execute the code as quietly possible.
user_variables : list, optional
A list of variable names to pull from the user's namespace. They
will come back as a dict with these names as keys and their
:func:`repr` as values.
user_expressions : dict, optional
A dict with string keys and to pull from the user's
namespace. They will come back as a dict with these names as keys
and their :func:`repr` as values.
allow_stdin : bool, optional
Flag for
A dict with string keys and to pull from the user's
namespace. They will come back as a dict with these names as keys
and their :func:`repr` as values.
Returns
-------
The msg_id of the message sent.
"""
if user_variables is None:
user_variables = []
if user_expressions is None:
user_expressions = {}
if allow_stdin is None:
allow_stdin = self.allow_stdin
# Don't waste network traffic if inputs are invalid
if not isinstance(code, basestring):
raise ValueError('code %r must be a string' % code)
validate_string_list(user_variables)
validate_string_dict(user_expressions)
# Create class for content/msg creation. Related to, but possibly
# not in Session.
content = dict(code=code, silent=silent,
user_variables=user_variables,
user_expressions=user_expressions,
allow_stdin=allow_stdin,
)
msg = self.session.msg('execute_request', content)
self._queue_send(msg)
return msg['header']['msg_id']
def complete(self, text, line, cursor_pos, block=None):
"""Tab complete text in the kernel's namespace.
Parameters
----------
text : str
The text to complete.
line : str
The full line of text that is the surrounding context for the
text to complete.
cursor_pos : int
The position of the cursor in the line where the completion was
requested.
block : str, optional
The full block of code in which the completion is being requested.
Returns
-------
The msg_id of the message sent.
"""
content = dict(text=text, line=line, block=block, cursor_pos=cursor_pos)
msg = self.session.msg('complete_request', content)
self._queue_send(msg)
return msg['header']['msg_id']
def object_info(self, oname, detail_level=0):
"""Get metadata information about an object.
Parameters
----------
oname : str
A string specifying the object name.
detail_level : int, optional
The level of detail for the introspection (0-2)
Returns
-------
The msg_id of the message sent.
"""
content = dict(oname=oname, detail_level=detail_level)
msg = self.session.msg('object_info_request', content)
self._queue_send(msg)
return msg['header']['msg_id']
def history(self, raw=True, output=False, hist_access_type='range', **kwargs):
"""Get entries from the history list.
Parameters
----------
raw : bool
If True, return the raw input.
output : bool
If True, then return the output as well.
hist_access_type : str
'range' (fill in session, start and stop params), 'tail' (fill in n)
or 'search' (fill in pattern param).
session : int
For a range request, the session from which to get lines. Session
numbers are positive integers; negative ones count back from the
current session.
start : int
The first line number of a history range.
stop : int
The final (excluded) line number of a history range.
n : int
The number of lines of history to get for a tail request.
pattern : str
The glob-syntax pattern for a search request.
Returns
-------
The msg_id of the message sent.
"""
content = dict(raw=raw, output=output, hist_access_type=hist_access_type,
**kwargs)
msg = self.session.msg('history_request', content)
self._queue_send(msg)
return msg['header']['msg_id']
def shutdown(self, restart=False):
"""Request an immediate kernel shutdown.
Upon receipt of the (empty) reply, client code can safely assume that
the kernel has shut down and it's safe to forcefully terminate it if
it's still alive.
The kernel will send the reply via a function registered with Python's
atexit module, ensuring it's truly done as the kernel is done with all
normal operation.
"""
# Send quit message to kernel. Once we implement kernel-side setattr,
# this should probably be done that way, but for now this will do.
msg = self.session.msg('shutdown_request', {'restart':restart})
self._queue_send(msg)
return msg['header']['msg_id']
class SubSocketChannel(ZMQSocketChannel):
"""The SUB channel which listens for messages that the kernel publishes.
"""
def __init__(self, context, session, address):
super(SubSocketChannel, self).__init__(context, session, address)
self.ioloop = ioloop.IOLoop()
def run(self):
"""The thread's main activity. Call start() instead."""
self.socket = self.context.socket(zmq.SUB)
self.socket.setsockopt(zmq.SUBSCRIBE,b'')
self.socket.setsockopt(zmq.IDENTITY, self.session.bsession)
self.socket.connect('tcp://%s:%i' % self.address)
self.stream = zmqstream.ZMQStream(self.socket, self.ioloop)
self.stream.on_recv(self._handle_recv)
self._run_loop()
try:
self.socket.close()
except:
pass
def stop(self):
self.ioloop.stop()
super(SubSocketChannel, self).stop()
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 leve
handlers are called in the application thread.
"""
raise NotImplementedError('call_handlers must be defined in a subclass.')
def flush(self, timeout=1.0):
"""Immediately processes all pending messages on the SUB channel.
Callers should use this method to ensure that :method:`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 xrange(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 StdInSocketChannel(ZMQSocketChannel):
"""A reply channel to handle raw_input requests that the kernel makes."""
msg_queue = None
def __init__(self, context, session, address):
super(StdInSocketChannel, self).__init__(context, session, address)
self.ioloop = ioloop.IOLoop()
def run(self):
"""The thread's main activity. Call start() instead."""
self.socket = self.context.socket(zmq.DEALER)
self.socket.setsockopt(zmq.IDENTITY, self.session.bsession)
self.socket.connect('tcp://%s:%i' % self.address)
self.stream = zmqstream.ZMQStream(self.socket, self.ioloop)
self.stream.on_recv(self._handle_recv)
self._run_loop()
try:
self.socket.close()
except:
pass
def stop(self):
self.ioloop.stop()
super(StdInSocketChannel, self).stop()
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 leve
handlers are called in the application thread.
"""
raise NotImplementedError('call_handlers must be defined in a subclass.')
def input(self, string):
"""Send a string of raw input to the kernel."""
content = dict(value=string)
msg = self.session.msg('input_reply', content)
self._queue_send(msg)
class HBSocketChannel(ZMQSocketChannel):
"""The heartbeat channel which monitors the kernel heartbeat.
Note that the heartbeat channel is paused by default. As long as you start
this channel, the kernel manager will ensure that it is paused and un-paused
as appropriate.
"""
time_to_dead = 3.0
socket = None
poller = None
_running = None
_pause = None
_beating = None
def __init__(self, context, session, address):
super(HBSocketChannel, self).__init__(context, session, address)
self._running = False
self._pause =True
self.poller = zmq.Poller()
def _create_socket(self):
if self.socket is not None:
# close previous socket, before opening a new one
self.poller.unregister(self.socket)
self.socket.close()
self.socket = self.context.socket(zmq.REQ)
self.socket.setsockopt(zmq.LINGER, 0)
self.socket.connect('tcp://%s:%i' % self.address)
self.poller.register(self.socket, zmq.POLLIN)
def _poll(self, start_time):
"""poll for heartbeat replies until we reach self.time_to_dead
Ignores interrupts, and returns the result of poll(), which
will be an empty list if no messages arrived before the timeout,
or the event tuple if there is a message to receive.
"""
until_dead = self.time_to_dead - (time.time() - start_time)
# ensure poll at least once
until_dead = max(until_dead, 1e-3)
events = []
while True:
try:
events = self.poller.poll(1000 * until_dead)
except ZMQError as e:
if e.errno == errno.EINTR:
# ignore interrupts during heartbeat
# this may never actually happen
until_dead = self.time_to_dead - (time.time() - start_time)
until_dead = max(until_dead, 1e-3)
pass
else:
raise
except Exception:
if self._exiting:
break
else:
raise
else:
break
return events
def run(self):
"""The thread's main activity. Call start() instead."""
self._create_socket()
self._running = True
self._beating = True
while self._running:
if self._pause:
# just sleep, and skip the rest of the loop
time.sleep(self.time_to_dead)
continue
since_last_heartbeat = 0.0
# io.rprint('Ping from HB channel') # dbg
# no need to catch EFSM here, because the previous event was
# either a recv or connect, which cannot be followed by EFSM
self.socket.send(b'ping')
request_time = time.time()
ready = self._poll(request_time)
if ready:
self._beating = True
# the poll above guarantees we have something to recv
self.socket.recv()
# sleep the remainder of the cycle
remainder = self.time_to_dead - (time.time() - request_time)
if remainder > 0:
time.sleep(remainder)
continue
else:
# nothing was received within the time limit, signal heart failure
self._beating = False
since_last_heartbeat = time.time() - request_time
self.call_handlers(since_last_heartbeat)
# and close/reopen the socket, because the REQ/REP cycle has been broken
self._create_socket()
continue
try:
self.socket.close()
except:
pass
def pause(self):
"""Pause the heartbeat."""
self._pause = True
def unpause(self):
"""Unpause the heartbeat."""
self._pause = False
def is_beating(self):
"""Is the heartbeat running and responsive (and not paused)."""
if self.is_alive() and not self._pause and self._beating:
return True
else:
return False
def stop(self):
self._running = False
super(HBSocketChannel, self).stop()
def call_handlers(self, since_last_heartbeat):
"""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.
"""
raise NotImplementedError('call_handlers must be defined in a subclass.')
#-----------------------------------------------------------------------------
# Main kernel manager class
#-----------------------------------------------------------------------------
class KernelManager(HasTraits):
""" Manages a kernel for a frontend.
The SUB channel is for the frontend to receive messages published by the
kernel.
The REQ channel is for the frontend to make requests of the kernel.
The REP channel is for the kernel to request stdin (raw_input) from the
frontend.
"""
# config object for passing to child configurables
config = Instance(Config)
# The PyZMQ Context to use for communication with the kernel.
context = Instance(zmq.Context)
def _context_default(self):
return zmq.Context.instance()
# The Session to use for communication with the kernel.
session = Instance(Session)
# The kernel process with which the KernelManager is communicating.
kernel = Instance(Popen)
# The addresses for the communication channels.
connection_file = Unicode('')
ip = Unicode(LOCALHOST)
def _ip_changed(self, name, old, new):
if new == '*':
self.ip = '0.0.0.0'
shell_port = Integer(0)
iopub_port = Integer(0)
stdin_port = Integer(0)
hb_port = Integer(0)
# The classes to use for the various channels.
shell_channel_class = Type(ShellSocketChannel)
sub_channel_class = Type(SubSocketChannel)
stdin_channel_class = Type(StdInSocketChannel)
hb_channel_class = Type(HBSocketChannel)
# Protected traits.
_launch_args = Any
_shell_channel = Any
_sub_channel = Any
_stdin_channel = Any
_hb_channel = Any
_connection_file_written=Bool(False)
def __init__(self, **kwargs):
super(KernelManager, self).__init__(**kwargs)
if self.session is None:
self.session = Session(config=self.config)
def __del__(self):
self.cleanup_connection_file()
#--------------------------------------------------------------------------
# Channel management methods:
#--------------------------------------------------------------------------
def start_channels(self, shell=True, sub=True, stdin=True, hb=True):
"""Starts the channels for this kernel.
This will create the channels if they do not exist and then start
them. If port numbers of 0 are being used (random ports) then you
must first call :method:`start_kernel`. If the channels have been
stopped and you call this, :class:`RuntimeError` will be raised.
"""
if shell:
self.shell_channel.start()
if sub:
self.sub_channel.start()
if stdin:
self.stdin_channel.start()
self.shell_channel.allow_stdin = True
else:
self.shell_channel.allow_stdin = False
if hb:
self.hb_channel.start()
def stop_channels(self):
"""Stops all the running channels for this kernel.
"""
if self.shell_channel.is_alive():
self.shell_channel.stop()
if self.sub_channel.is_alive():
self.sub_channel.stop()
if self.stdin_channel.is_alive():
self.stdin_channel.stop()
if self.hb_channel.is_alive():
self.hb_channel.stop()
@property
def channels_running(self):
"""Are any of the channels created and running?"""
return (self.shell_channel.is_alive() or self.sub_channel.is_alive() or
self.stdin_channel.is_alive() or self.hb_channel.is_alive())
#--------------------------------------------------------------------------
# Kernel process management methods:
#--------------------------------------------------------------------------
def cleanup_connection_file(self):
"""cleanup connection file *if we wrote it*
Will not raise if the connection file was already removed somehow.
"""
if self._connection_file_written:
# cleanup connection files on full shutdown of kernel we started
self._connection_file_written = False
try:
os.remove(self.connection_file)
except OSError:
pass
def load_connection_file(self):
"""load connection info from JSON dict in self.connection_file"""
with open(self.connection_file) as f:
cfg = json.loads(f.read())
self.ip = cfg['ip']
self.shell_port = cfg['shell_port']
self.stdin_port = cfg['stdin_port']
self.iopub_port = cfg['iopub_port']
self.hb_port = cfg['hb_port']
self.session.key = str_to_bytes(cfg['key'])
def write_connection_file(self):
"""write connection info to JSON dict in self.connection_file"""
if self._connection_file_written:
return
self.connection_file,cfg = write_connection_file(self.connection_file,
ip=self.ip, key=self.session.key,
stdin_port=self.stdin_port, iopub_port=self.iopub_port,
shell_port=self.shell_port, hb_port=self.hb_port)
# write_connection_file also sets default ports:
self.shell_port = cfg['shell_port']
self.stdin_port = cfg['stdin_port']
self.iopub_port = cfg['iopub_port']
self.hb_port = cfg['hb_port']
self._connection_file_written = True
def start_kernel(self, **kw):
"""Starts a kernel process and configures the manager to use it.
If random ports (port=0) are being used, this method must be called
before the channels are created.
Parameters:
-----------
launcher : callable, optional (default None)
A custom function for launching the kernel process (generally a
wrapper around ``entry_point.base_launch_kernel``). In most cases,
it should not be necessary to use this parameter.
**kw : optional
See respective options for IPython and Python kernels.
"""
if self.ip not in LOCAL_IPS:
raise RuntimeError("Can only launch a kernel on a local interface. "
"Make sure that the '*_address' attributes are "
"configured properly. "
"Currently valid addresses are: %s"%LOCAL_IPS
)
# write connection file / get default ports
self.write_connection_file()
self._launch_args = kw.copy()
launch_kernel = kw.pop('launcher', None)
if launch_kernel is None:
from ipkernel import launch_kernel
self.kernel = launch_kernel(fname=self.connection_file, **kw)
def shutdown_kernel(self, restart=False):
""" Attempts to the stop the kernel process cleanly. If the kernel
cannot be stopped, it is killed, if possible.
"""
# FIXME: Shutdown does not work on Windows due to ZMQ errors!
if sys.platform == 'win32':
self.kill_kernel()
return
# Pause the heart beat channel if it exists.
if self._hb_channel is not None:
self._hb_channel.pause()
# Don't send any additional kernel kill messages immediately, to give
# the kernel a chance to properly execute shutdown actions. Wait for at
# most 1s, checking every 0.1s.
self.shell_channel.shutdown(restart=restart)
for i in range(10):
if self.is_alive:
time.sleep(0.1)
else:
break
else:
# OK, we've waited long enough.
if self.has_kernel:
self.kill_kernel()
if not restart and self._connection_file_written:
# cleanup connection files on full shutdown of kernel we started
self._connection_file_written = False
try:
os.remove(self.connection_file)
except IOError:
pass
def restart_kernel(self, now=False, **kw):
"""Restarts a kernel with the arguments that were used to launch it.
If the old kernel was launched with random ports, the same ports will be
used for the new kernel.
Parameters
----------
now : bool, optional
If True, the kernel is forcefully restarted *immediately*, without
having a chance to do any cleanup action. Otherwise the kernel is
given 1s to clean up before a forceful restart is issued.
In all cases the kernel is restarted, the only difference is whether
it is given a chance to perform a clean shutdown or not.
**kw : optional
Any options specified here will replace those used to launch the
kernel.
"""
if self._launch_args is None:
raise RuntimeError("Cannot restart the kernel. "
"No previous call to 'start_kernel'.")
else:
# Stop currently running kernel.
if self.has_kernel:
if now:
self.kill_kernel()
else:
self.shutdown_kernel(restart=True)
# Start new kernel.
self._launch_args.update(kw)
self.start_kernel(**self._launch_args)
# FIXME: Messages get dropped in Windows due to probable ZMQ bug
# unless there is some delay here.
if sys.platform == 'win32':
time.sleep(0.2)
@property
def has_kernel(self):
"""Returns whether a kernel process has been specified for the kernel
manager.
"""
return self.kernel is not None
def kill_kernel(self):
""" Kill the running kernel. """
if self.has_kernel:
# Pause the heart beat channel if it exists.
if self._hb_channel is not None:
self._hb_channel.pause()
# Attempt to kill the kernel.
try:
self.kernel.kill()
except OSError, e:
# In Windows, we will get an Access Denied error if the process
# has already terminated. Ignore it.
if sys.platform == 'win32':
if e.winerror != 5:
raise
# On Unix, we may get an ESRCH error if the process has already
# terminated. Ignore it.
else:
from errno import ESRCH
if e.errno != ESRCH:
raise
self.kernel = None
else:
raise RuntimeError("Cannot kill kernel. No kernel is running!")
def interrupt_kernel(self):
""" Interrupts the kernel. Unlike ``signal_kernel``, this operation is
well supported on all platforms.
"""
if self.has_kernel:
if sys.platform == 'win32':
from parentpoller import ParentPollerWindows as Poller
Poller.send_interrupt(self.kernel.win32_interrupt_event)
else:
self.kernel.send_signal(signal.SIGINT)
else:
raise RuntimeError("Cannot interrupt kernel. No kernel is running!")
def signal_kernel(self, signum):
""" Sends a signal to the kernel. Note that since only SIGTERM is
supported on Windows, this function is only useful on Unix systems.
"""
if self.has_kernel:
self.kernel.send_signal(signum)
else:
raise RuntimeError("Cannot signal kernel. No kernel is running!")
@property
def is_alive(self):
"""Is the kernel process still running?"""
if self.has_kernel:
if self.kernel.poll() is None:
return True
else:
return False
elif self._hb_channel is not None:
# We didn't start the kernel with this KernelManager so we
# use the heartbeat.
return self._hb_channel.is_beating()
else:
# no heartbeat and not local, we can't tell if it's running,
# so naively return True
return True
#--------------------------------------------------------------------------
# Channels used for communication with the kernel:
#--------------------------------------------------------------------------
@property
def shell_channel(self):
"""Get the REQ socket channel object to make requests of the kernel."""
if self._shell_channel is None:
self._shell_channel = self.shell_channel_class(self.context,
self.session,
(self.ip, self.shell_port))
return self._shell_channel
@property
def sub_channel(self):
"""Get the SUB socket channel object."""
if self._sub_channel is None:
self._sub_channel = self.sub_channel_class(self.context,
self.session,
(self.ip, self.iopub_port))
return self._sub_channel
@property
def stdin_channel(self):
"""Get the REP socket channel object to handle stdin (raw_input)."""
if self._stdin_channel is None:
self._stdin_channel = self.stdin_channel_class(self.context,
self.session,
(self.ip, self.stdin_port))
return self._stdin_channel
@property
def hb_channel(self):
"""Get the heartbeat socket channel object to check that the
kernel is alive."""
if self._hb_channel is None:
self._hb_channel = self.hb_channel_class(self.context,
self.session,
(self.ip, self.hb_port))
return self._hb_channel
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