214 lines
6.9 KiB
Python
214 lines
6.9 KiB
Python
"""Base classes to manage a Client's interaction with a running kernel"""
|
|
|
|
# Copyright (c) Jupyter Development Team.
|
|
# Distributed under the terms of the Modified BSD License.
|
|
|
|
import atexit
|
|
import errno
|
|
from threading import Thread, Event
|
|
import time
|
|
import asyncio
|
|
|
|
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 jupyter_client import protocol_version_info
|
|
|
|
from .channelsabc import HBChannelABC
|
|
|
|
#-----------------------------------------------------------------------------
|
|
# Constants and exceptions
|
|
#-----------------------------------------------------------------------------
|
|
|
|
major_protocol_version = protocol_version_info[0]
|
|
|
|
class InvalidPortNumber(Exception):
|
|
pass
|
|
|
|
class HBChannel(Thread):
|
|
"""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.
|
|
"""
|
|
context = None
|
|
session = None
|
|
socket = None
|
|
address = None
|
|
_exiting = False
|
|
|
|
time_to_dead = 1.
|
|
poller = None
|
|
_running = None
|
|
_pause = None
|
|
_beating = None
|
|
|
|
def __init__(self, context=None, session=None, address=None, loop=None):
|
|
"""Create the heartbeat monitor thread.
|
|
|
|
Parameters
|
|
----------
|
|
context : :class:`zmq.Context`
|
|
The ZMQ context to use.
|
|
session : :class:`session.Session`
|
|
The session to use.
|
|
address : zmq url
|
|
Standard (ip, port) tuple that the kernel is listening on.
|
|
"""
|
|
super(HBChannel, self).__init__()
|
|
self.daemon = True
|
|
|
|
self.loop = loop
|
|
|
|
self.context = context
|
|
self.session = session
|
|
if isinstance(address, tuple):
|
|
if address[1] == 0:
|
|
message = 'The port number for a channel cannot be 0.'
|
|
raise InvalidPortNumber(message)
|
|
address = "tcp://%s:%i" % address
|
|
self.address = address
|
|
|
|
# running is False until `.start()` is called
|
|
self._running = False
|
|
self._exit = Event()
|
|
# don't start paused
|
|
self._pause = False
|
|
self.poller = zmq.Poller()
|
|
|
|
@staticmethod
|
|
@atexit.register
|
|
def _notice_exit():
|
|
# Class definitions can be torn down during interpreter shutdown.
|
|
# We only need to set _exiting flag if this hasn't happened.
|
|
if HBChannel is not None:
|
|
HBChannel._exiting = True
|
|
|
|
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.linger = 1000
|
|
self.socket.connect(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."""
|
|
if self.loop is not None:
|
|
asyncio.set_event_loop(self.loop)
|
|
self._create_socket()
|
|
self._running = True
|
|
self._beating = True
|
|
|
|
while self._running:
|
|
if self._pause:
|
|
# just sleep, and skip the rest of the loop
|
|
self._exit.wait(self.time_to_dead)
|
|
continue
|
|
|
|
since_last_heartbeat = 0.0
|
|
# 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:
|
|
self._exit.wait(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
|
|
|
|
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):
|
|
"""Stop the channel's event loop and join its thread."""
|
|
self._running = False
|
|
self._exit.set()
|
|
self.join()
|
|
self.close()
|
|
|
|
def close(self):
|
|
if self.socket is not None:
|
|
try:
|
|
self.socket.close(linger=0)
|
|
except Exception:
|
|
pass
|
|
self.socket = None
|
|
|
|
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.
|
|
"""
|
|
pass
|
|
|
|
|
|
HBChannelABC.register(HBChannel)
|