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# Copyright 2019, Battelle Memorial Institute.
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import logging
import urllib.parse
import uuid
import os
import gevent
from volttron import platform
from volttron.platform import get_home
from volttron.platform.agent.utils import get_aware_utc_now
from volttron.platform.vip.agent import Agent
from volttron.platform import build_vip_address_string
__version__ = '1.0.3'
__author__ = 'Craig Allwardt <craig.allwardt@pnnl.gov>'
DEFAULT_TIMEOUT = 30
[docs]class Connection(object):
""" A class that manages a connection to a peer and/or server.
"""
def __init__(self, address, peer=None, publickey=None,
secretkey=None, serverkey=None, volttron_home=None,
instance_name=None, message_bus=None, **kwargs):
self._log = logging.getLogger(__name__)
self._log.debug("Connection: {}, {}, {}, {}, {}, {}"
.format(address, peer, publickey, secretkey, serverkey, message_bus))
self._address = address
self._peer = peer
self._serverkey = None
if peer is None:
self._log.warn('Peer is non so must be passed in call method.')
self.volttron_home = volttron_home
if self.volttron_home is None:
self.volttron_home = os.path.abspath(platform.get_home())
if address.startswith('ipc'):
full_address = address
else:
parsed = urllib.parse.urlparse(address)
if parsed.scheme == 'tcp':
qs = urllib.parse.parse_qs(parsed.query)
self._log.debug('QS IS: {}'.format(qs))
if 'serverkey' in qs:
self._serverkey = qs.get('serverkey')
else:
self._serverkey = serverkey
# Handle case when the address has all the information in it.
if 'serverkey' in qs and 'publickey' in qs and \
'secretkey' in qs:
full_address = address
else:
full_address = build_vip_address_string(
vip_root=address, serverkey=serverkey,
publickey=publickey, secretkey=secretkey
)
elif parsed.scheme == 'ipc':
full_address = address
else:
raise AttributeError(
'Invalid address type specified. ipc or tcp accepted.')
self._server = Agent(address=full_address,
volttron_home=self.volttron_home,
enable_store=False,
reconnect_interval=1000,
instance_name=instance_name,
message_bus=message_bus,
**kwargs)
# TODO the following should work as well, but doesn't. Not sure why!
# self._server = Agent(address=address, serverkey=serverkey,
# secretkey=secretkey, publickey=publickey,
# enable_store=False,
# volttron_home=self.volttron_home, **kwargs)
self._greenlet = None
self._connected_since = None
self._last_publish = None
self._last_publish_failed = False
self._last_rpc_call = None
# Make the actual attempt to connect to the server.
self.is_connected()
@property
def serverkey(self):
return self._serverkey
@property
def last_publish_failed(self):
return self._last_publish_failed
@property
def connected_since(self):
return self._connected_since
@property
def last_publish(self):
return self._last_publish
@property
def last_rpc_call(self):
return self._last_rpc_call
@property
def address(self):
return self._address
@property
def peer(self):
return self._peer
@property
def server(self):
if self._greenlet is None:
event = gevent.event.Event()
self._greenlet = gevent.spawn(self._server.core.run, event)
try:
with gevent.Timeout(DEFAULT_TIMEOUT):
event.wait()
except gevent.Timeout:
self.kill()
self._greenlet = None
raise
self._connected_since = get_aware_utc_now()
if self.peer:
if self.peer not in self._server.vip.peerlist().get(timeout=2):
self._log.warn('peer {} not found connected to router.'.format(
self.peer
))
return self._server
[docs] def peers(self, timeout=DEFAULT_TIMEOUT):
return self.server.vip.peerlist().get(timeout=timeout)
[docs] def is_connected(self, timeout=DEFAULT_TIMEOUT):
return self.server.core.connected and self.is_peer_connected(timeout)
[docs] def is_peer_connected(self, timeout=DEFAULT_TIMEOUT):
self._log.debug('Checking for peer {}'.format(self.peer))
return self.peer in self.peers()
[docs] def publish(self, topic, headers=None, message=None, timeout=DEFAULT_TIMEOUT):
if timeout is None:
raise ValueError('timeout cannot be None')
timeout = int(timeout)
self.server.vip.pubsub.publish(
'pubsub', topic=topic, headers=headers, message=message
).get(timeout=timeout)
[docs] def subscribe(self, prefix, callback):
self.server.vip.pubsub.subscribe('pubsub', prefix, callback)
[docs] def call(self, method, *args, **kwargs):
timeout = kwargs.pop('timeout', DEFAULT_TIMEOUT)
peer = kwargs.pop('peer', None)
if peer is not None:
return self.server.vip.rpc.call(
peer, method, *args, **kwargs).get(timeout=timeout)
if self.peer is not None:
return self.server.vip.rpc.call(
self.peer, method, *args, **kwargs).get(timeout=timeout)
raise ValueError("peer not specified on class or as method argument.")
[docs] def notify(self, method, *args, **kwargs):
peer = kwargs.pop('peer')
if peer is not None:
return self.server.vip.rpc.notify(
peer, method, *args, **kwargs)
if self.peer is not None:
return self.server.vip.rpc.notify(
self.peer, method, *args, **kwargs)
raise ValueError("peer not specified on class or as method argument.")
[docs] def kill(self, *args, **kwargs):
if self._greenlet is not None:
self._greenlet.kill(*args, **kwargs)
del(self._greenlet)
self._greenlet = None