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"""
policy-receiver communicates with policy-engine
thru web-socket to receive push notifications
on updates and removal of policies.
on receiving the policy-notifications, the policy-receiver
filters them out by the policy scope(s) provided in policy-handler config
and passes the notifications to policy-updater
"""
# org.onap.dcae
# ================================================================================
# Copyright (c) 2017 AT&T Intellectual Property. All rights reserved.
# ================================================================================
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ============LICENSE_END=========================================================
#
# ECOMP is a trademark and service mark of AT&T Intellectual Property.
import json
import logging
import re
import time
from threading import Lock, Thread
import websocket
from .config import Config
from .onap.audit import Audit
from .policy_updater import PolicyUpdater
LOADED_POLICIES = 'loadedPolicies'
REMOVED_POLICIES = 'removedPolicies'
POLICY_NAME = 'policyName'
POLICY_VER = 'versionNo'
class _PolicyReceiver(Thread):
"""web-socket to PolicyEngine"""
_logger = logging.getLogger("policy_handler.policy_receiver")
def __init__(self):
"""web-socket inside the thread to receive policy notifications from PolicyEngine"""
Thread.__init__(self, name="policy_receiver")
self.daemon = True
self._lock = Lock()
self._keep_running = True
config = Config.config[Config.FIELD_POLICY_ENGINE]
self.web_socket_url = resturl = config["url"] + config["path_pdp"]
if resturl.startswith("https:"):
self.web_socket_url = resturl.replace("https:", "wss:") + "notifications"
else:
self.web_socket_url = resturl.replace("http:", "ws:") + "notifications"
self._web_socket = None
scope_prefixes = [scope_prefix.replace(".", "[.]")
for scope_prefix in Config.config["scope_prefixes"]]
self._policy_scopes = re.compile("(" + "|".join(scope_prefixes) + ")")
_PolicyReceiver._logger.info("_policy_scopes %s", self._policy_scopes.pattern)
self._policy_updater = PolicyUpdater()
self._policy_updater.start()
def run(self):
"""listen on web-socket and pass the policy notifications to policy-updater"""
websocket.enableTrace(True)
restarting = False
while True:
if not self._get_keep_running():
break
self._stop_notifications()
if restarting:
time.sleep(5)
_PolicyReceiver._logger.info(
"connecting to policy-notifications at: %s", self.web_socket_url)
self._web_socket = websocket.WebSocketApp(
self.web_socket_url,
on_message=self._on_pdp_message,
on_close=self._on_ws_close,
on_error=self._on_ws_error
)
_PolicyReceiver._logger.info("waiting for policy-notifications...")
self._web_socket.run_forever()
restarting = True
_PolicyReceiver._logger.info("exit policy-receiver")
def _get_keep_running(self):
"""thread-safe check whether to continue running"""
with self._lock:
keep_running = self._keep_running
return keep_running
def _stop_notifications(self):
"""Shuts down the AutoNotification service if running."""
with self._lock:
if self._web_socket and self._web_socket.sock and self._web_socket.sock.connected:
self._web_socket.close()
_PolicyReceiver._logger.info("Stopped receiving notifications from PDP")
def _on_pdp_message(self, _, message):
"""received the notification from PDP"""
_PolicyReceiver._logger.info("Received notification message: %s", message)
if not message:
return
message = json.loads(message)
if not message:
return
policies_updated = [(policy.get(POLICY_NAME), policy.get(POLICY_VER))
for policy in message.get(LOADED_POLICIES, [])
if self._policy_scopes.match(policy.get(POLICY_NAME))]
policies_removed = [(policy.get(POLICY_NAME), policy.get(POLICY_VER))
for policy in message.get(REMOVED_POLICIES, [])
if self._policy_scopes.match(policy.get(POLICY_NAME))]
if not policies_updated and not policies_removed:
_PolicyReceiver._logger.info(
"no policy updated or removed for scopes %s", self._policy_scopes.pattern
)
return
audit = Audit(req_message="policy-notification - updated[{0}], removed[{1}]" \
.format(len(policies_updated), len(policies_removed)))
audit.retry_get_config = True
self._policy_updater.enqueue(audit, policies_updated, policies_removed)
def _on_ws_error(self, _, error):
"""report an error"""
_PolicyReceiver._logger.error("policy-notification error: %s", error)
def _on_ws_close(self, _):
"""restart web-socket on close"""
_PolicyReceiver._logger.info("lost connection to PDP - restarting...")
def shutdown(self, audit):
"""Shutdown the policy-receiver"""
_PolicyReceiver._logger.info("shutdown policy-receiver")
with self._lock:
self._keep_running = False
self._stop_notifications()
if self.is_alive():
self.join()
self._policy_updater.shutdown(audit)
def catch_up(self, audit):
"""need to bring the latest policies to DCAE-Controller"""
self._policy_updater.catch_up(audit)
class PolicyReceiver(object):
"""policy-receiver - static singleton wrapper"""
_policy_receiver = None
@staticmethod
def shutdown(audit):
"""Shutdown the notification-handler"""
PolicyReceiver._policy_receiver.shutdown(audit)
@staticmethod
def catch_up(audit):
"""bring the latest policies from policy-engine"""
PolicyReceiver._policy_receiver.catch_up(audit)
@staticmethod
def run(audit):
"""Using policy-engine client to talk to policy engine"""
sub_aud = Audit(aud_parent=audit)
sub_aud.metrics_start("start policy receiver")
PolicyReceiver._policy_receiver = _PolicyReceiver()
PolicyReceiver._policy_receiver.start()
sub_aud.metrics("started policy receiver")
PolicyReceiver.catch_up(audit)
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