[PMSH] Improve CBS data handling

  # AppConfog object fetch priodically
  # AAI client to only fetch AAI data

Signed-off-by: efiacor <fiachra.corcoran@est.tech>
Change-Id: I78315f141c3bb7e8b0d9efa818d294415fa79918
Issue-ID: DCAEGEN2-2146

8 files changed, 90 insertions, 60 deletions

diff --git a/components/pm-subscription-handler/pmsh_service/mod/__init__.py b/components/pm-subscription-handler/pmsh_service/mod/__init__.py
index 316687c0..efc61aae 100644
--- a/components/pm-subscription-handler/pmsh_service/mod/__init__.py
+++ b/components/pm-subscription-handler/pmsh_service/mod/__init__.py
@@ -59,7 +59,7 @@ def create_app():
 
 def create_logger():
     config_file_path = os.getenv('LOGGER_CONFIG')
-    update_config(config_file_path)
+    update_logging_config(config_file_path)
     monkey.patch_loggingYaml()
     logging.config.yamlConfig(filepath=config_file_path,
                               watchDog=os.getenv('DYNAMIC_LOGGER_CONFIG', True))
@@ -73,7 +73,7 @@ def create_logger():
     logging.setLogRecordFactory(augment_record)
 
 
-def update_config(config_file_path):
+def update_logging_config(config_file_path):
     config_yaml = YAML()
     config_file = pathlib.Path(config_file_path)
     data = config_yaml.load(config_file)
diff --git a/components/pm-subscription-handler/pmsh_service/mod/aai_client.py b/components/pm-subscription-handler/pmsh_service/mod/aai_client.py
index 371fdb06..2b92df41 100755
--- a/components/pm-subscription-handler/pmsh_service/mod/aai_client.py
+++ b/components/pm-subscription-handler/pmsh_service/mod/aai_client.py
@@ -22,39 +22,39 @@ import requests
 from requests.auth import HTTPBasicAuth
 
 from mod import logger
+from mod.network_function import NetworkFunction
 from mod.pmsh_utils import mdc_handler
-from mod.network_function import NetworkFunction, NetworkFunctionFilter
-from mod.subscription import Subscription
 
 
-def get_pmsh_subscription_data(cbs_data):
+def get_pmsh_nfs_from_aai(app_conf):
     """
-    Returns the PMSH subscription data
+    Returns the Network Functions from AAI related to the Subscription.
 
     Args:
-        cbs_data: json app config from the Config Binding Service.
+        app_conf (AppConfig): the AppConfig object.
 
     Returns:
-        Subscription, set(NetworkFunctions): `Subscription` <Subscription> object,
-        set of NetworkFunctions to be added.
+        set(NetworkFunctions): set of NetworkFunctions.
 
     Raises:
-        RuntimeError: if AAI data cannot be retrieved.
+        RuntimeError: if AAI Network Function data cannot be retrieved.
     """
-    aai_nf_data = _get_all_aai_nf_data()
+    aai_nf_data = _get_all_aai_nf_data(app_conf)
     if aai_nf_data:
-        sub = Subscription(**cbs_data['policy']['subscription'])
-        nfs = _filter_nf_data(aai_nf_data, NetworkFunctionFilter(**sub.nfFilter))
+        nfs = _filter_nf_data(aai_nf_data, app_conf.nf_filter)
     else:
         raise RuntimeError('Failed to get data from AAI')
-    return sub, nfs
+    return nfs
 
 
 @mdc_handler
-def _get_all_aai_nf_data(**kwargs):
+def _get_all_aai_nf_data(app_conf, **kwargs):
     """
     Return queried nf data from the AAI service.
 
+    Args:
+        app_conf (AppConfig): the AppConfig object.
+
     Returns:
         dict: the json response from AAI query, else None.
     """
@@ -77,7 +77,8 @@ def _get_all_aai_nf_data(**kwargs):
                     }"""
         params = {'format': 'simple', 'nodesOnly': 'true'}
         response = session.put(aai_endpoint, headers=headers,
-                               auth=HTTPBasicAuth('AAI', 'AAI'),
+                               auth=HTTPBasicAuth(app_conf.aaf_creds.get('aaf_id'),
+                                                  app_conf.aaf_creds.get('aaf_pass')),
                                data=json_data, params=params, verify=False)
         response.raise_for_status()
         if response.ok:
diff --git a/components/pm-subscription-handler/pmsh_service/mod/aai_event_handler.py b/components/pm-subscription-handler/pmsh_service/mod/aai_event_handler.py
index 5aebb926..96f51431 100755
--- a/components/pm-subscription-handler/pmsh_service/mod/aai_event_handler.py
+++ b/components/pm-subscription-handler/pmsh_service/mod/aai_event_handler.py
@@ -20,8 +20,7 @@ import json
 from enum import Enum
 
 from mod import logger
-from mod.network_function import NetworkFunction, NetworkFunctionFilter
-from mod.subscription import AdministrativeState
+from mod.network_function import NetworkFunction
 
 
 class XNFType(Enum):
@@ -34,13 +33,12 @@ class AAIEvent(Enum):
     UPDATE = 'UPDATE'
 
 
-def process_aai_events(mr_sub, subscription, mr_pub, app, app_conf):
+def process_aai_events(mr_sub, mr_pub, app, app_conf):
     """
     Processes AAI UPDATE events for each filtered xNFs where orchestration status is set to Active.
 
     Args:
         mr_sub (_MrSub): MR subscriber
-        subscription (Subscription): The current subscription object
         mr_pub (_MrPub): MR publisher
         app (db): DB application
         app_conf (AppConfig): the application configuration.
@@ -48,7 +46,7 @@ def process_aai_events(mr_sub, subscription, mr_pub, app, app_conf):
     app.app_context().push()
     aai_events = mr_sub.get_from_topic('AAI-EVENT')
 
-    if _aai_event_exists(aai_events):
+    if aai_events is not None and len(aai_events) != 0:
         for entry in aai_events:
             logger.debug(f'AAI-EVENT entry: {entry}')
             entry = json.loads(entry)
@@ -60,19 +58,18 @@ def process_aai_events(mr_sub, subscription, mr_pub, app, app_conf):
                 'vnf-name']
             new_status = aai_xnf['orchestration-status']
 
-            if NetworkFunctionFilter(**subscription.nfFilter).is_nf_in_filter(xnf_name, new_status):
-                _process_event(action, new_status, xnf_name, subscription, mr_pub, app_conf)
+            if app_conf.nf_filter.is_nf_in_filter(xnf_name, new_status):
+                _process_event(action, new_status, xnf_name, mr_pub, app_conf)
 
 
-def _process_event(action, new_status, xnf_name, subscription, mr_pub, app_conf):
+def _process_event(action, new_status, xnf_name, mr_pub, app_conf):
     if action == AAIEvent.UPDATE.value:
         logger.info(f'Update event found for network function {xnf_name}')
         local_xnf = NetworkFunction.get(xnf_name)
 
         if local_xnf is None:
             logger.info(f'Activating subscription for network function {xnf_name}')
-            subscription.administrativeState = AdministrativeState.UNLOCKED.value
-            subscription.process_subscription([NetworkFunction(
+            app_conf.subscription.process_subscription([NetworkFunction(
                 nf_name=xnf_name, orchestration_status=new_status)], mr_pub, app_conf)
         else:
             logger.debug(f"Update Event for network function {xnf_name} will not be processed "
@@ -81,7 +78,3 @@ def _process_event(action, new_status, xnf_name, subscription, mr_pub, app_conf)
         logger.info(f'Delete event found for network function {xnf_name}')
         NetworkFunction.delete(nf_name=xnf_name)
         logger.info(f'{xnf_name} successfully deleted.')
-
-
-def _aai_event_exists(aai_events):
-    return aai_events is not None and len(aai_events) != 0
diff --git a/components/pm-subscription-handler/pmsh_service/mod/network_function.py b/components/pm-subscription-handler/pmsh_service/mod/network_function.py
index aa39bf2c..979cc775 100755
--- a/components/pm-subscription-handler/pmsh_service/mod/network_function.py
+++ b/components/pm-subscription-handler/pmsh_service/mod/network_function.py
@@ -102,8 +102,8 @@ class NetworkFunctionFilter:
         """Match the nf name against regex values in Subscription.nfFilter.nfNames
 
         Args:
-            nf_name: the AAI nf name.
-            orchestration_status: orchestration status of the nf
+            nf_name (str): the AAI nf name.
+            orchestration_status (str): orchestration status of the nf
 
         Returns:
             bool: True if matched, else False.
diff --git a/components/pm-subscription-handler/pmsh_service/mod/pmsh_utils.py b/components/pm-subscription-handler/pmsh_service/mod/pmsh_utils.py
index 01661ad0..fb6a5194 100755
--- a/components/pm-subscription-handler/pmsh_service/mod/pmsh_utils.py
+++ b/components/pm-subscription-handler/pmsh_service/mod/pmsh_utils.py
@@ -15,6 +15,7 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 # ============LICENSE_END=====================================================
+import threading
 import uuid
 from os import getenv
 from threading import Timer
@@ -26,6 +27,8 @@ from requests.auth import HTTPBasicAuth
 from tenacity import wait_fixed, stop_after_attempt, retry, retry_if_exception_type
 
 from mod import logger
+from mod.network_function import NetworkFunctionFilter
+from mod.subscription import Subscription
 
 
 def mdc_handler(function):
@@ -42,12 +45,40 @@ def mdc_handler(function):
     return decorator
 
 
-class ConfigHandler:
-    """ Handles retrieval of PMSH's configuration from Configbinding service."""
-    @staticmethod
+class ThreadSafeSingleton(type):
+    _instances = {}
+    _singleton_lock = threading.Lock()
+
+    def __call__(cls, *args, **kwargs):
+        # double-checked locking pattern (https://en.wikipedia.org/wiki/Double-checked_locking)
+        if cls not in cls._instances:
+            with cls._singleton_lock:
+                if cls not in cls._instances:
+                    cls._instances[cls] = super(ThreadSafeSingleton, cls).__call__(*args, **kwargs)
+        return cls._instances[cls]
+
+
+class AppConfig(metaclass=ThreadSafeSingleton):
+
+    def __init__(self):
+        try:
+            conf = self._get_pmsh_config()
+        except Exception:
+            raise
+        self.aaf_creds = {'aaf_id': conf['config'].get('aaf_identity'),
+                          'aaf_pass': conf['config'].get('aaf_password')}
+        self.cert_path = conf['config'].get('cert_path')
+        self.key_path = conf['config'].get('key_path')
+        self.streams_subscribes = conf['config'].get('streams_subscribes')
+        self.streams_publishes = conf['config'].get('streams_publishes')
+        self.operational_policy_name = conf['config'].get('operational_policy_name')
+        self.control_loop_name = conf['config'].get('control_loop_name')
+        self.subscription = Subscription(**conf['policy']['subscription'])
+        self.nf_filter = NetworkFunctionFilter(**self.subscription.nfFilter)
+
     @mdc_handler
     @retry(wait=wait_fixed(2), stop=stop_after_attempt(5), retry=retry_if_exception_type(Exception))
-    def get_pmsh_config(**kwargs):
+    def _get_pmsh_config(self, **kwargs):
         """ Retrieves PMSH's configuration from Config binding service. If a non-2xx response
         is received, it retries after 2 seconds for 5 times before raising an exception.
 
@@ -66,17 +97,23 @@ class ConfigHandler:
             logger.error(f'Failed to get config from CBS: {err}')
             raise Exception
 
+    def refresh_config(self):
+        """
+        Update the relevant attributes of the AppConfig object.
 
-class AppConfig:
-    def __init__(self, **kwargs):
-        self.aaf_creds = {'aaf_id': kwargs.get('aaf_identity'),
-                          'aaf_pass': kwargs.get('aaf_password')}
-        self.cert_path = kwargs.get('cert_path')
-        self.key_path = kwargs.get('key_path')
-        self.streams_subscribes = kwargs.get('streams_subscribes')
-        self.streams_publishes = kwargs.get('streams_publishes')
-        self.operational_policy_name = kwargs.get('operational_policy_name')
-        self.control_loop_name = kwargs.get('control_loop_name')
+        Raises:
+            Exception: if cbs request fails.
+        """
+        try:
+            app_conf = self._get_pmsh_config()
+        except Exception:
+            logger.debug("Failed to refresh AppConfig data")
+            raise
+        self.subscription.administrativeState = \
+            app_conf['policy']['subscription']['administrativeState']
+        self.nf_filter.nf_names = app_conf['policy']['subscription']['nfFilter']['nfNames']
+        self.nf_filter.nf_sw_version = app_conf['policy']['subscription']['nfFilter']['swVersions']
+        logger.info("AppConfig data has been refreshed")
 
     def get_mr_sub(self, sub_name):
         """
diff --git a/components/pm-subscription-handler/pmsh_service/mod/policy_response_handler.py b/components/pm-subscription-handler/pmsh_service/mod/policy_response_handler.py
index 5ce03691..2b917cec 100644
--- a/components/pm-subscription-handler/pmsh_service/mod/policy_response_handler.py
+++ b/components/pm-subscription-handler/pmsh_service/mod/policy_response_handler.py
@@ -37,9 +37,9 @@ policy_response_handle_functions = {
 
 
 class PolicyResponseHandler:
-    def __init__(self, mr_sub, subscription_name, app):
+    def __init__(self, mr_sub, app_conf, app):
         self.mr_sub = mr_sub
-        self.subscription_name = subscription_name
+        self.app_conf = app_conf
         self.app = app
 
     @retry(wait=wait_fixed(5), retry=retry_if_exception_type(Exception))
@@ -48,18 +48,19 @@ class PolicyResponseHandler:
         This method polls MR for response from policy. It checks whether the message is for the
         relevant subscription and then handles the response
         """
-        logger.info('Polling MR started for XNF activation/deactivation policy response events.')
         self.app.app_context().push()
-        administrative_state = Subscription.get(self.subscription_name).status
+        administrative_state = self.app_conf.subscription.administrativeState
+        logger.info('Polling MR started for XNF activation/deactivation policy response events.')
         try:
             response_data = self.mr_sub.get_from_topic('policy_response_consumer')
             for data in response_data:
                 data = json.loads(data)
-                if data['status']['subscriptionName'] == self.subscription_name:
+                if data['status']['subscriptionName'] \
+                        == self.app_conf.subscription.subscriptionName:
                     nf_name = data['status']['nfName']
                     response_message = data['status']['message']
-                    self._handle_response(self.subscription_name, administrative_state,
-                                          nf_name, response_message)
+                    self._handle_response(self.app_conf.subscription.subscriptionName,
+                                          administrative_state, nf_name, response_message)
         except Exception as err:
             raise Exception(f'Error trying to poll policy response topic on MR: {err}')
 
diff --git a/components/pm-subscription-handler/pmsh_service/mod/subscription.py b/components/pm-subscription-handler/pmsh_service/mod/subscription.py
index be217b11..d6b17cd9 100755
--- a/components/pm-subscription-handler/pmsh_service/mod/subscription.py
+++ b/components/pm-subscription-handler/pmsh_service/mod/subscription.py
@@ -125,7 +125,7 @@ class Subscription:
             logger.debug(f'Failed to add nf {nf.nf_name} to subscription '
                          f'{current_sub.subscription_name}: {e}')
             logger.debug(f'Subscription {current_sub.subscription_name} now contains these XNFs:'
-                         f'{Subscription.get_nfs_per_subscription(current_sub.subscription_name)}')
+                         f'{Subscription.get_nf_names_per_sub(current_sub.subscription_name)}')
 
     @staticmethod
     def get(subscription_name):
@@ -206,9 +206,9 @@ class Subscription:
         self.update_subscription_status()
 
         if self.administrativeState == AdministrativeState.UNLOCKED.value:
-            logger.info(f'{action} subscription initiated for {self.subscriptionName}.')
             action = 'Activate'
             sub_nf_state = SubNfState.PENDING_CREATE.value
+            logger.info(f'{action} subscription initiated for {self.subscriptionName}.')
 
         try:
             for nf in nfs:
@@ -228,7 +228,6 @@ class Subscription:
             list: NetworkFunctions per Subscription list else empty
         """
         nf_per_subscriptions = NfSubRelationalModel.query.all()
-
         return nf_per_subscriptions
 
     @staticmethod
diff --git a/components/pm-subscription-handler/pmsh_service/mod/subscription_handler.py b/components/pm-subscription-handler/pmsh_service/mod/subscription_handler.py
index be67cae6..add8be42 100644
--- a/components/pm-subscription-handler/pmsh_service/mod/subscription_handler.py
+++ b/components/pm-subscription-handler/pmsh_service/mod/subscription_handler.py
@@ -17,7 +17,6 @@
 # ============LICENSE_END=====================================================
 
 import mod.aai_client as aai
-from mod.pmsh_utils import ConfigHandler
 from mod import logger
 from mod.subscription import AdministrativeState
 
@@ -38,15 +37,15 @@ class SubscriptionHandler:
         the Subscription if a change has occurred
         """
         self.app.app_context().push()
-        config = ConfigHandler.get_pmsh_config()
-        new_administrative_state = config['policy']['subscription']['administrativeState']
+        new_administrative_state = self.app_conf.subscription.administrativeState
         try:
             if self.administrative_state == new_administrative_state:
                 logger.info('Administrative State did not change in the Config')
             else:
                 logger.info(f'Administrative State has changed from {self.administrative_state} '
                             f'to {new_administrative_state}.')
-                self.current_sub, self.current_nfs = aai.get_pmsh_subscription_data(config)
+                self.current_nfs = aai.get_pmsh_nfs_from_aai(self.app_conf)
+                self.current_sub = self.app_conf.subscription
                 self.administrative_state = new_administrative_state
                 self.current_sub.process_subscription(self.current_nfs, self.mr_pub, self.app_conf)