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heartmonitor.py
193 lines | 7.1 KiB | text/x-python | PythonLexer
#!/usr/bin/env python
"""
A multi-heart Heartbeat system using PUB and ROUTER sockets. pings are sent out on the PUB,
and hearts are tracked based on their DEALER identities.
"""
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
from __future__ import print_function
import time
import uuid
import zmq
from zmq.devices import ThreadDevice, ThreadMonitoredQueue
from zmq.eventloop import ioloop, zmqstream
from IPython.config.configurable import LoggingConfigurable
from IPython.utils.py3compat import str_to_bytes
from IPython.utils.traitlets import Set, Instance, CFloat, Integer, Dict, Bool
from IPython.parallel.util import log_errors
class Heart(object):
"""A basic heart object for responding to a HeartMonitor.
This is a simple wrapper with defaults for the most common
Device model for responding to heartbeats.
It simply builds a threadsafe zmq.FORWARDER Device, defaulting to using
SUB/DEALER for in/out.
You can specify the DEALER's IDENTITY via the optional heart_id argument."""
device=None
id=None
def __init__(self, in_addr, out_addr, mon_addr=None, in_type=zmq.SUB, out_type=zmq.DEALER, mon_type=zmq.PUB, heart_id=None):
if mon_addr is None:
self.device = ThreadDevice(zmq.FORWARDER, in_type, out_type)
else:
self.device = ThreadMonitoredQueue(in_type, out_type, mon_type, in_prefix=b"", out_prefix=b"")
# do not allow the device to share global Context.instance,
# which is the default behavior in pyzmq > 2.1.10
self.device.context_factory = zmq.Context
self.device.daemon=True
self.device.connect_in(in_addr)
self.device.connect_out(out_addr)
if mon_addr is not None:
self.device.connect_mon(mon_addr)
if in_type == zmq.SUB:
self.device.setsockopt_in(zmq.SUBSCRIBE, b"")
if heart_id is None:
heart_id = uuid.uuid4().bytes
self.device.setsockopt_out(zmq.IDENTITY, heart_id)
self.id = heart_id
def start(self):
return self.device.start()
class HeartMonitor(LoggingConfigurable):
"""A basic HeartMonitor class
pingstream: a PUB stream
pongstream: an ROUTER stream
period: the period of the heartbeat in milliseconds"""
debug = Bool(False, config=True,
help="""Whether to include every heartbeat in debugging output.
Has to be set explicitly, because there will be *a lot* of output.
"""
)
period = Integer(3000, config=True,
help='The frequency at which the Hub pings the engines for heartbeats '
'(in ms)',
)
max_heartmonitor_misses = Integer(10, config=True,
help='Allowed consecutive missed pings from controller Hub to engine before unregistering.',
)
pingstream=Instance('zmq.eventloop.zmqstream.ZMQStream')
pongstream=Instance('zmq.eventloop.zmqstream.ZMQStream')
loop = Instance('zmq.eventloop.ioloop.IOLoop')
def _loop_default(self):
return ioloop.IOLoop.instance()
# not settable:
hearts=Set()
responses=Set()
on_probation=Dict()
last_ping=CFloat(0)
_new_handlers = Set()
_failure_handlers = Set()
lifetime = CFloat(0)
tic = CFloat(0)
def __init__(self, **kwargs):
super(HeartMonitor, self).__init__(**kwargs)
self.pongstream.on_recv(self.handle_pong)
def start(self):
self.tic = time.time()
self.caller = ioloop.PeriodicCallback(self.beat, self.period, self.loop)
self.caller.start()
def add_new_heart_handler(self, handler):
"""add a new handler for new hearts"""
self.log.debug("heartbeat::new_heart_handler: %s", handler)
self._new_handlers.add(handler)
def add_heart_failure_handler(self, handler):
"""add a new handler for heart failure"""
self.log.debug("heartbeat::new heart failure handler: %s", handler)
self._failure_handlers.add(handler)
def beat(self):
self.pongstream.flush()
self.last_ping = self.lifetime
toc = time.time()
self.lifetime += toc-self.tic
self.tic = toc
if self.debug:
self.log.debug("heartbeat::sending %s", self.lifetime)
goodhearts = self.hearts.intersection(self.responses)
missed_beats = self.hearts.difference(goodhearts)
newhearts = self.responses.difference(goodhearts)
for heart in newhearts:
self.handle_new_heart(heart)
heartfailures, on_probation = self._check_missed(missed_beats, self.on_probation,
self.hearts)
for failure in heartfailures:
self.handle_heart_failure(failure)
self.on_probation = on_probation
self.responses = set()
#print self.on_probation, self.hearts
# self.log.debug("heartbeat::beat %.3f, %i beating hearts", self.lifetime, len(self.hearts))
self.pingstream.send(str_to_bytes(str(self.lifetime)))
# flush stream to force immediate socket send
self.pingstream.flush()
def _check_missed(self, missed_beats, on_probation, hearts):
"""Update heartbeats on probation, identifying any that have too many misses.
"""
failures = []
new_probation = {}
for cur_heart in (b for b in missed_beats if b in hearts):
miss_count = on_probation.get(cur_heart, 0) + 1
self.log.info("heartbeat::missed %s : %s" % (cur_heart, miss_count))
if miss_count > self.max_heartmonitor_misses:
failures.append(cur_heart)
else:
new_probation[cur_heart] = miss_count
return failures, new_probation
def handle_new_heart(self, heart):
if self._new_handlers:
for handler in self._new_handlers:
handler(heart)
else:
self.log.info("heartbeat::yay, got new heart %s!", heart)
self.hearts.add(heart)
def handle_heart_failure(self, heart):
if self._failure_handlers:
for handler in self._failure_handlers:
try:
handler(heart)
except Exception as e:
self.log.error("heartbeat::Bad Handler! %s", handler, exc_info=True)
pass
else:
self.log.info("heartbeat::Heart %s failed :(", heart)
self.hearts.remove(heart)
@log_errors
def handle_pong(self, msg):
"a heart just beat"
current = str_to_bytes(str(self.lifetime))
last = str_to_bytes(str(self.last_ping))
if msg[1] == current:
delta = time.time()-self.tic
if self.debug:
self.log.debug("heartbeat::heart %r took %.2f ms to respond", msg[0], 1000*delta)
self.responses.add(msg[0])
elif msg[1] == last:
delta = time.time()-self.tic + (self.lifetime-self.last_ping)
self.log.warn("heartbeat::heart %r missed a beat, and took %.2f ms to respond", msg[0], 1000*delta)
self.responses.add(msg[0])
else:
self.log.warn("heartbeat::got bad heartbeat (possibly old?): %s (current=%.3f)", msg[1], self.lifetime)