# -*- coding: utf-8 -*- {{{
# 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 errno
import logging
import gevent
from zmq import green as zmq
from base64 import b64encode, b64decode
from zmq import SNDMORE
from volttron.platform.vip.agent import Agent, Core, RPC
from volttron.platform.vip.agent.errors import VIPError
from volttron.platform import jsonrpc, jsonapi
from collections import defaultdict
_log = logging.getLogger(__name__)
[docs]def encode_peer(peer):
if peer.startswith('\x00'):
return peer[:1] + b64encode(peer[1:])
return peer
[docs]def decode_peer(peer):
if peer.startswith('\x00'):
return peer[:1] + b64decode(peer[1:])
return peer
[docs]class PubSubWrapper(Agent):
"""PubSubWrapper Agent acts as a wrapper agent for PubSub subsystem when connected to remote platform that which is using
old pubsub (RPC based implementation).
When it receives PubSub requests from remote platform,
- calls the appropriate method of new platform.
- returns the result back"""
def __init__(self, identity, **kwargs):
super(PubSubWrapper, self).__init__(identity, **kwargs)
def subscriptions():
return defaultdict(set)
self._peer_subscriptions = defaultdict(subscriptions)
[docs] @Core.receiver('onsetup')
def onsetup(self, sender, **kwargs):
# pylint: disable=unused-argument
self.vip.rpc.export(self._peer_sync, 'pubsub.sync')
self.vip.rpc.export(self._peer_publish, 'pubsub.publish')
self.vip.rpc.export(self._peer_subscribe, 'pubsub.subscribe')
self.vip.rpc.export(self._peer_unsubscribe, 'pubsub.unsubscribe')
self.vip.rpc.export(self._peer_list, 'pubsub.list')
def _sync(self, peer, items):
items = {(bus, prefix) for bus, topics in items.items()
for prefix in topics}
remove = []
for bus, subscriptions in self._peer_subscriptions.items():
for prefix, subscribers in subscriptions.items():
item = bus, prefix
try:
items.remove(item)
except KeyError:
subscribers.discard(peer)
if not subscribers:
remove.append(item)
else:
subscribers.add(peer)
for bus, prefix in remove:
subscriptions = self._peer_subscriptions[bus]
assert not subscriptions.pop(prefix)
for bus, prefix in items:
self._add_peer_subscription(peer, bus, prefix)
self.vip.pubsub.subscribe(peer, prefix, self._collector, bus=bus)
def _peer_sync(self, items):
peer = bytes(self.vip.rpc.context.vip_message.peer).decode("utf-8")
assert isinstance(items, dict)
self._sync(peer, items)
def _peer_publish(self, topic, headers, message=None, bus=''):
peer = bytes(self.vip.rpc.context.vip_message.peer).decode("utf-8")
self.vip.pubsub.publish(peer, topic, headers, message=message, bus=bus)
[docs] def add_bus(self, name):
self._peer_subscriptions.setdefault(name, {})
def _add_peer_subscription(self, peer, bus, prefix):
self._peer_subscriptions[bus][prefix].add(peer)
def _peer_subscribe(self, prefix, bus=''):
peer = bytes(self.vip.rpc.context.vip_message.peer).decode("utf-8")
for prefix in prefix if isinstance(prefix, list) else [prefix]:
self._add_peer_subscription(peer, bus, prefix)
self.vip.pubsub.subscribe(peer, prefix, self._collector, bus=bus)
def _distribute(self, peer, topic, headers, message=None, bus=''):
#self._check_if_protected_topic(topic)
subscriptions = self._peer_subscriptions[bus]
subscribers = set()
for prefix, subscription in subscriptions.items():
if subscription and topic.startswith(prefix):
subscribers |= subscription
if subscribers:
sender = encode_peer(peer)
json_msg = jsonapi.dumps(jsonrpc.json_method(
None, 'pubsub.push',
[sender, bus, topic, headers, message], None))
frames = [zmq.Frame(b''), zmq.Frame(b''),
zmq.Frame(b'RPC'), zmq.Frame(json_msg)]
socket = self.core.socket
for subscriber in subscribers:
socket.send(subscriber, flags=SNDMORE)
socket.send_multipart(frames, copy=False)
return len(subscribers)
def _collector(self, peer, sender, bus, topic, headers, message):
self._distribute(peer, topic, headers, message, bus)
def _peer_list(self, prefix='', bus='', subscribed=True, reverse=False):
peer = bytes(self.vip.rpc.context.vip_message.peer).decode("utf-8")
if bus is None:
buses = iter(self._peer_subscriptions.items())
else:
buses = [(bus, self._peer_subscriptions[bus])]
if reverse:
test = prefix.startswith
else:
test = lambda t: t.startswith(prefix)
results = []
for bus, subscriptions in buses:
for topic, subscribers in subscriptions.items():
if test(topic):
member = peer in subscribers
if not subscribed or member:
results.append((bus, topic, member))
return results
def _peer_unsubscribe(self, prefix, bus=''):
peer = bytes(self.vip.rpc.context.vip_message.peer).decode("utf-8")
subscriptions = self._peer_subscriptions[bus]
if prefix is None:
remove = []
for topic, subscribers in subscriptions.items():
subscribers.discard(peer)
if not subscribers:
remove.append(topic)
for topic in remove:
del subscriptions[topic]
self.vip.pubsub.unsubscribe(peer, prefix, self._collector, bus=bus)
else:
for prefix in prefix if isinstance(prefix, list) else [prefix]:
subscribers = subscriptions[prefix]
subscribers.discard(peer)
if not subscribers:
del subscriptions[prefix]
self.vip.pubsub.unsubscribe(peer, prefix, self._collector, bus=bus)