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client.py
249 lines | 7.3 KiB | text/x-python | PythonLexer
""" Defines a KernelClient that provides signals and slots.
"""
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
from IPython.external.qt import QtCore
# Local imports
from IPython.utils.traitlets import Type, Instance
from IPython.kernel.channels import HBChannel
from IPython.kernel import KernelClient
from .kernel_mixins import QtKernelClientMixin
from .util import SuperQObject
class QtHBChannel(SuperQObject, HBChannel):
# A longer timeout than the base class
time_to_dead = 3.0
# Emitted when the kernel has died.
kernel_died = QtCore.Signal(object)
def call_handlers(self, since_last_heartbeat):
""" Reimplemented to emit signals instead of making callbacks.
"""
# Emit the generic signal.
self.kernel_died.emit(since_last_heartbeat)
from IPython.core.release import kernel_protocol_version_info
major_protocol_version = kernel_protocol_version_info[0]
class InvalidPortNumber(Exception):
pass
class QtZMQSocketChannel(SuperQObject):
"""A ZMQ socket emitting a Qt signal when a message is received."""
session = None
socket = None
ioloop = None
stream = None
message_received = QtCore.Signal(object)
def process_events(self):
""" Process any pending GUI events.
"""
QtCore.QCoreApplication.instance().processEvents()
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(QtZMQSocketChannel, 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)
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.
"""
# Emit the generic signal.
self.message_received.emit(msg)
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 QtKernelClient(QtKernelClientMixin, KernelClient):
""" A KernelClient that provides signals and slots.
"""
_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.message_received.connect(self._check_kernel_info_reply)
self.ioloop_thread = IOLoopThread(self.ioloop)
self.ioloop_thread.start()
super(QtKernelClient, self).start_channels(shell, iopub, stdin, hb)
def _check_kernel_info_reply(self, msg):
if msg['msg_type'] == 'kernel_info_reply':
self._handle_kernel_info_reply(msg)
self.shell_channel.message_received.disconnect(self._check_kernel_info_reply)
def stop_channels(self):
super(QtKernelClient, self).stop_channels()
if self.ioloop_thread.is_alive():
self.ioloop_thread.stop()
iopub_channel_class = Type(QtZMQSocketChannel)
shell_channel_class = Type(QtZMQSocketChannel)
stdin_channel_class = Type(QtZMQSocketChannel)
hb_channel_class = Type(QtHBChannel)