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avoid executing code in utils.localinterfaces at import time...
avoid executing code in utils.localinterfaces at import time moves away from global constants to utility functions. The code is still only executed once, but instead of at import time, it is executed at first request.

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heartbeat.py
67 lines | 2.3 KiB | text/x-python | PythonLexer
"""The client and server for a basic ping-pong style heartbeat.
"""
#-----------------------------------------------------------------------------
# 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
#-----------------------------------------------------------------------------
import errno
import os
import socket
from threading import Thread
import zmq
from IPython.utils.localinterfaces import localhost
#-----------------------------------------------------------------------------
# Code
#-----------------------------------------------------------------------------
class Heartbeat(Thread):
"A simple ping-pong style heartbeat that runs in a thread."
def __init__(self, context, addr=None):
if addr is None:
addr = ('tcp', localhost(), 0)
Thread.__init__(self)
self.context = context
self.transport, self.ip, self.port = addr
if self.port == 0:
if addr[0] == 'tcp':
s = socket.socket()
# '*' means all interfaces to 0MQ, which is '' to socket.socket
s.bind(('' if self.ip == '*' else self.ip, 0))
self.port = s.getsockname()[1]
s.close()
elif addr[0] == 'ipc':
self.port = 1
while os.path.exists("%s-%s" % (self.ip, self.port)):
self.port = self.port + 1
else:
raise ValueError("Unrecognized zmq transport: %s" % addr[0])
self.addr = (self.ip, self.port)
self.daemon = True
def run(self):
self.socket = self.context.socket(zmq.REP)
c = ':' if self.transport == 'tcp' else '-'
self.socket.bind('%s://%s' % (self.transport, self.ip) + c + str(self.port))
while True:
try:
zmq.device(zmq.FORWARDER, self.socket, self.socket)
except zmq.ZMQError as e:
if e.errno == errno.EINTR:
continue
else:
raise
else:
break