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# vim: set fenc=utf-8 ft=python sw=4 ts=4 sts=4 et:
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# Copyright 2019, Battelle Memorial Institute.
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import logging
import weakref
from .base import SubsystemBase
from ..dispatch import Signal
from ..results import ResultsDictionary
from volttron.platform import jsonapi
from zmq import ZMQError
from zmq.green import ENOTSOCK
__all__ = ['PeerList']
_log = logging.getLogger(__name__)
[docs]class PeerList(SubsystemBase):
def __init__(self, core):
self.core = weakref.ref(core)
self._results = ResultsDictionary()
core.register('peerlist', self._handle_subsystem, self._handle_error)
self.onadd = Signal()
self.ondrop = Signal()
self.peers_list = set()
[docs] def list(self):
connection = self.core().connection
result = next(self._results)
try:
connection.send_vip('',
'peerlist',
args=['list'],
msg_id=result.ident)
except ZMQError as exc:
if exc.errno == ENOTSOCK:
_log.error("Socket send on non socket {}".format(self.core().identity))
return result
[docs] def add_peer(self, peer, message_bus=None):
connection = self.core().connection
result = next(self._results)
if not message_bus:
message_bus = self.core().messagebus
try:
connection.send_vip('',
'peerlist',
args=['add', peer, message_bus],
msg_id=result.ident)
except ZMQError as exc:
if exc.errno == ENOTSOCK:
_log.error("Socket send on non socket {}".format(self.core().identity))
return result
[docs] def drop_peer(self, peer, message_bus=None):
connection = self.core().connection
result = next(self._results)
if not message_bus:
message_bus = self.core().messagebus
try:
connection.send_vip('',
'peerlist',
args=['drop', peer, message_bus],
msg_id=result.ident)
except ZMQError as exc:
if exc.errno == ENOTSOCK:
_log.error("Socket send on non socket {}".format(self.core().identity))
return result
[docs] def list_with_messagebus(self):
connection = self.core().connection
result = next(self._results)
try:
connection.send_vip('',
'peerlist',
args=['list_with_messagebus'],
msg_id=result.ident)
except ZMQError as exc:
if exc.errno == ENOTSOCK:
_log.error("Socket send on non socket {}".format(self.core().identity))
return result
__call__ = list
def _handle_subsystem(self, message):
try:
op = message.args[0]
except IndexError:
_log.error('missing peerlist subsystem operation')
return
if op in ['add', 'drop']:
try:
peer = message.args[1]
except IndexError:
_log.error('missing peerlist identity in %s operation', op)
return
message_bus = None
try:
message_bus = message.args[2]
except IndexError:
pass
# getattr requires a string
onop = 'on' + op
if message_bus:
getattr(self, onop).send(self, peer=peer, message_bus=message_bus)
else:
getattr(self, onop).send(self, peer=peer)
if op == 'add':
self.peers_list.add(peer)
else:
if peer in self.peers_list:
self.peers_list.remove(peer)
elif op == 'listing':
try:
result = self._results.pop(message.id)
except KeyError:
return
peers = [arg for arg in message.args[1:]]
result.set(peers)
self.peers_list = set(peers)
elif op == 'listing_with_messagebus':
try:
result = self._results.pop(message.id)
except KeyError:
return
result.set(jsonapi.loads(message.args[1]))
else:
_log.error('unknown peerlist subsystem operation == {}'.format(op))
def _handle_error(self, sender, message, error, **kwargs):
try:
result = self._results.pop(message.id)
except KeyError:
return
result.set_exception(error)