Handle graceful exit of PMSH1.0.2

Issue-ID: DCAEGEN2-1832
Change-Id: If0362e1927f7013d25f0cf23ade5ce9d2bdea8e3
Signed-off-by: emartin <ephraim.martin@est.tech>

4 files changed, 70 insertions, 11 deletions

diff --git a/components/pm-subscription-handler/pmsh_service/mod/exit_handler.py b/components/pm-subscription-handler/pmsh_service/mod/exit_handler.py
new file mode 100755
index 00000000..adc4941c
--- /dev/null
+++ b/components/pm-subscription-handler/pmsh_service/mod/exit_handler.py
@@ -0,0 +1,48 @@
+# ============LICENSE_START===================================================
+#  Copyright (C) 2020 Nordix Foundation.
+# ============================================================================
+# 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.
+#
+# SPDX-License-Identifier: Apache-2.0
+# ============LICENSE_END=====================================================
+
+from mod.pmsh_utils import logger
+from mod.subscription import AdministrativeState
+
+
+class ExitHandler:
+    """ Handles PMSH graceful exit when a SIGTERM signal is received.
+
+    Args:
+        periodic_tasks (List[PeriodicTask]): PeriodicTasks that needs to be cancelled.
+        subscription_handler (SubscriptionHandler): The subscription handler instance.
+    """
+
+    shutdown_signal_received = False
+
+    def __init__(self, *, periodic_tasks, subscription_handler):
+        self.periodic_tasks = periodic_tasks
+        self.subscription_handler = subscription_handler
+
+    def __call__(self, sig_num, frame):
+        logger.debug(f'ExitHandler was called with signal number: {sig_num}.')
+        current_sub = self.subscription_handler.current_sub
+        if current_sub and current_sub.administrativeState == AdministrativeState.UNLOCKED.value:
+            for thread in self.periodic_tasks:
+                logger.debug(f'Cancelling periodic task with thread name: {thread.name}.')
+                thread.cancel()
+            current_sub.administrativeState = AdministrativeState.LOCKED.value
+            current_sub.process_subscription(self.subscription_handler.current_nfs,
+                                             self.subscription_handler.mr_pub,
+                                             self.subscription_handler.app_conf)
+        ExitHandler.shutdown_signal_received = True
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 1fc3a097..750b7211 100755
--- a/components/pm-subscription-handler/pmsh_service/mod/pmsh_utils.py
+++ b/components/pm-subscription-handler/pmsh_service/mod/pmsh_utils.py
@@ -17,10 +17,12 @@
 # ============LICENSE_END=====================================================
 
 import uuid
+from threading import Timer
+
 import requests
-import mod.pmsh_logging as logger
 from requests.auth import HTTPBasicAuth
-from threading import Timer
+
+import mod.pmsh_logging as logger
 
 
 class AppConfig:
@@ -180,5 +182,6 @@ class PeriodicTask(Timer):
     """
 
     def run(self):
+        self.function(*self.args, **self.kwargs)
         while not self.finished.wait(self.interval):
             self.function(*self.args, **self.kwargs)
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 a615aa77..40b8c962 100644
--- a/components/pm-subscription-handler/pmsh_service/mod/subscription_handler.py
+++ b/components/pm-subscription-handler/pmsh_service/mod/subscription_handler.py
@@ -22,14 +22,16 @@ from mod.subscription import AdministrativeState
 
 
 class SubscriptionHandler:
-    def __init__(self, config_handler, administrative_state, mr_pub,
-                 aai_event_thread, app, app_conf):
+    def __init__(self, config_handler, administrative_state, mr_pub, app, app_conf,
+                 aai_event_thread):
+        self.current_nfs = None
+        self.current_sub = None
         self.config_handler = config_handler
         self.administrative_state = administrative_state
         self.mr_pub = mr_pub
-        self.aai_event_thread = aai_event_thread
         self.app = app
         self.app_conf = app_conf
+        self.aai_event_thread = aai_event_thread
 
     def execute(self):
         """
@@ -44,9 +46,9 @@ class SubscriptionHandler:
             if self.administrative_state == new_administrative_state:
                 logger.debug('Administrative State did not change in the Config')
             else:
-                sub, network_functions = aai.get_pmsh_subscription_data(config)
+                self.current_sub, self.current_nfs = aai.get_pmsh_subscription_data(config)
                 self.administrative_state = new_administrative_state
-                sub.process_subscription(network_functions, self.mr_pub, self.app_conf)
+                self.current_sub.process_subscription(self.current_nfs, self.mr_pub, self.app_conf)
 
                 if new_administrative_state == AdministrativeState.UNLOCKED.value:
                     logger.debug('Listening to AAI-EVENT topic in MR.')
diff --git a/components/pm-subscription-handler/pmsh_service/pmsh_service_main.py b/components/pm-subscription-handler/pmsh_service/pmsh_service_main.py
index af5aece2..60cf89c0 100755
--- a/components/pm-subscription-handler/pmsh_service/pmsh_service_main.py
+++ b/components/pm-subscription-handler/pmsh_service/pmsh_service_main.py
@@ -17,16 +17,18 @@
 # ============LICENSE_END=====================================================
 
 import sys
+from signal import signal, SIGTERM
 
 import mod.aai_client as aai
 import mod.pmsh_logging as logger
 from mod import db, create_app, launch_api_server
+from mod.aai_event_handler import process_aai_events
 from mod.config_handler import ConfigHandler
+from mod.exit_handler import ExitHandler
 from mod.pmsh_utils import AppConfig, PeriodicTask
 from mod.policy_response_handler import PolicyResponseHandler
 from mod.subscription import Subscription, AdministrativeState
 from mod.subscription_handler import SubscriptionHandler
-from mod.aai_event_handler import process_aai_events
 
 
 def main():
@@ -46,17 +48,21 @@ def main():
             else AdministrativeState.LOCKED.value
 
         aai_event_thread = PeriodicTask(10, process_aai_events,
-                                        args=(mr_aai_event_sub, sub, policy_mr_pub, app, app_conf))
+                                        args=(mr_aai_event_sub,
+                                              sub, policy_mr_pub, app, app_conf))
         subscription_handler = SubscriptionHandler(config_handler, administrative_state,
-                                                   policy_mr_pub, aai_event_thread, app, app_conf)
+                                                   policy_mr_pub, app, app_conf, aai_event_thread)
         policy_response_handler = PolicyResponseHandler(policy_mr_sub, sub.subscriptionName, app)
 
         subscription_handler_thread = PeriodicTask(30, subscription_handler.execute)
         policy_response_handler_thread = PeriodicTask(5, policy_response_handler.poll_policy_topic)
-
         subscription_handler_thread.start()
         policy_response_handler_thread.start()
+        periodic_tasks = [aai_event_thread, subscription_handler_thread,
+                          policy_response_handler_thread]
 
+        signal(SIGTERM, ExitHandler(periodic_tasks=periodic_tasks,
+                                    subscription_handler=subscription_handler))
         launch_api_server(app_conf)
 
     except Exception as e: