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import logging
import weakref
from .base import SubsystemBase
from ..errors import VIPError
from ..results import ResultsDictionary
from volttron.platform.vip.socket import Message
from zmq import ZMQError
from zmq.green import ENOTSOCK
__all__ = ['Ping']
_log = logging.getLogger(__name__)
[docs]class Ping(SubsystemBase):
def __init__(self, core):
self.core = weakref.ref(core)
self._results = ResultsDictionary()
core.register('ping', self._handle_ping, self._handle_error)
[docs] def ping(self, peer, *args):
result = next(self._results)
args = list(args)
args.insert(0, 'ping')
connection = self.core().connection
try:
connection.send_vip('',
'ping',
args=['drop', peer],
msg_id=result.ident)
except ZMQError as exc:
if exc.errno == ENOTSOCK:
_log.debug("Socket send on non socket {}".format(self.core().identity))
return result
__call__ = ping
def _handle_ping(self, message):
connection = self.core().connection
try:
op = message.args[0]
except IndexError:
_log.error('missing ping subsystem operation')
return
if op == 'ping':
message.user = ''
message.args[0] = 'pong'
connection.send_vip_object(message, copy=False)
elif op == 'pong':
try:
result = self._results.pop(message.id)
except KeyError:
return
result.set([arg for arg in message.args[1:]])
else:
_log.error('unknown ping subsystem operation')
def _handle_error(self, sender, message, error, **kwargs):
try:
result = self._results.pop(message.id)
except KeyError:
return
result.set_exception(error)