""" 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 jupyter_client.channels import HBChannel from jupyter_client import KernelClient from jupyter_client.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, allow_none=True) 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)