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'''VIP - VOLTTRON™ Interconnect Protocol implementation
See https://volttron.readthedocs.io/en/develop/core_services/messagebus/VIP/VIP-Overview.html
for protocol specification.
This module is for use within gevent. It provides some locking around
send operations to protect the VIP state. It should be safe to use a
single socket in multiple greenlets without any kind of locking.
'''
from contextlib import contextmanager as _contextmanager
from gevent import sleep as _sleep
from gevent.local import local as _local
from gevent.lock import RLock as _RLock
from zmq.green import NOBLOCK, POLLOUT
from zmq import green as _green
from . import *
from .router import BaseRouter as _BaseRouter
from .socket import _Socket
[docs]class Socket(_Socket, _green.Socket):
_context_class = _green.Context
_local_class = _local
def __init__(self, *args, **kwargs):
super(Socket, self).__init__(*args, **kwargs)
object.__setattr__(self, '_Socket__send_lock', _RLock())
@_contextmanager
def _sending(self, flags):
flags |= getattr(self._Socket__local, 'flags', 0)
lock = self._Socket__send_lock
while not lock.acquire(not flags & NOBLOCK):
if not self.poll(0, POLLOUT):
raise _green.Again()
_sleep(0)
try:
yield flags
finally:
lock.release()
[docs]class BaseRouter(_BaseRouter):
_context_class = _green.Context
_socket_class = _green.Socket