Feature 8840 Notification to OSS/BSS for subscribed events.
[osm/NBI.git] / osm_nbi / notifications.py
diff --git a/osm_nbi/notifications.py b/osm_nbi/notifications.py
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+# Copyright 2020 K Sai Kiran (Tata Elxsi)
+#
+# 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.
+
+__author__ = "K Sai Kiran <saikiran.k@tataelxsi.co.in>"
+__date__ = "$28-Apr-2020 23:59:59$"
+
+import asyncio
+import aiohttp
+from http import HTTPStatus
+import json
+import logging
+import time
+from uuid import uuid4
+
+
+class NotificationException(Exception):
+    """
+    Notification Exception
+    """
+
+    def __init__(self, message: str, http_code: int = HTTPStatus.BAD_REQUEST) -> None:
+        """
+        Constructor of notification exception
+        :param message: String text containing exception details.
+        :param http_code: HTTP status code of exception.
+        """
+        self.http_code = http_code
+        Exception.__init__(self, message)
+
+
+class NotificationBase:
+
+    response_models = None
+    # Common HTTP payload header for all notifications.
+    payload_header = {
+        "Content-Type": "application/json",
+        "Accept": "application/json"
+    }
+
+    def __init__(self, db) -> None:
+        """
+        Constructor of NotificationBase class.
+        :param db: Database handler.
+        """
+        self.db = db
+        self.logger = logging.getLogger("nbi.notifications")
+        self.subscriber_collection = None
+
+    def get_models(self) -> dict:
+        """
+        Returns the SOL005 model of notification class
+        :param None
+        :return: dict of SOL005 data model
+        """
+        return NotificationBase.response_models
+
+    def get_subscribers(self, **kwargs) -> NotificationException:
+        """
+        Method should be implemented by all notification subclasses
+        :param kwargs: any keyword arguments needed for db query.
+        :return: List of subscribers
+        """
+        raise NotificationException("Method get_subscribers() is not implemented", http_code=HTTPStatus.NOT_IMPLEMENTED)
+
+    @staticmethod
+    def _get_basic_auth(username: str, password: str) -> tuple:
+        return aiohttp.BasicAuth(username, password)
+
+    def _decrypt_password(self, hashed: str, salt: str, schema_version: str = "1.1") -> str:
+        return self.db.decrypt(hashed, schema_version, salt=salt)
+
+    def get_payload(self, meta_notification: dict) -> dict:
+        """
+        Generates SOL005 compliant payload structure and returns them in dictionary.
+        :param meta_notification: notification meta data which needs to be formatted as SOL005 compliant
+        :return: A dictionary which is SOL005 compliant.
+        """
+        model_name = meta_notification["notificationType"]
+        response_models = self.get_models()
+        if not response_models or not response_models.get(model_name):
+            raise NotificationException("Response model {} is not defined.".format(model_name),
+                                        HTTPStatus.NOT_IMPLEMENTED)
+        model_keys = response_models[model_name]
+        payload = dict.fromkeys(model_keys, "N/A")
+        notification_keys = set(meta_notification.keys())
+        for model_key in model_keys.intersection(notification_keys):
+            payload[model_key] = meta_notification[model_key]
+        self.logger.debug("Payload generated for subscriber: {} for {}".format(payload["subscriptionId"],
+                                                                               payload["notificationType"]))
+        return payload
+
+    async def send_notifications(self, subscribers: list, loop: asyncio.AbstractEventLoop = None):
+        """
+        Generate tasks for all notification for an event.
+        :param subscribers: A list of subscribers who want to be notified for event.
+        :param loop: Event loop object.
+        """
+        notifications = []
+        for subscriber in subscribers:
+            # TODO add support for AuthType OAuth and TLS after support is added in subscription.
+            if subscriber["authentication"]["authType"] != "basic":
+                self.logger.debug("Subscriber {} can not be notified {} notification auth type is not implemented"
+                                  .format(subscriber["subscriptionId"],
+                                          subscriber["authentication"]["authType"]))
+                continue
+            salt = subscriber["subscriptionId"]
+            hashed_password = subscriber["authentication"]["paramsBasic"]["password"]
+            password = self._decrypt_password(hashed_password, salt)
+            auth_basic = self._get_basic_auth(subscriber["authentication"]["paramsBasic"]["userName"], password)
+            notifications.append({
+                "headers": self.payload_header,
+                "payload": self.get_payload(subscriber),
+                "auth_basic": auth_basic,
+                "CallbackUri": subscriber["CallbackUri"]
+            })
+        tasks = []
+        async with aiohttp.ClientSession(loop=loop) as session:
+            for notification in notifications:
+                tasks.append(asyncio.ensure_future(self.send_notification(session, notification), loop=loop))
+            await asyncio.gather(*tasks, loop=loop)
+
+    async def send_notification(self, session: aiohttp.ClientSession, notification: dict,
+                                loop: asyncio.AbstractEventLoop = None, retry_count: int = 5, timeout: float = 5.0):
+        """
+        Performs HTTP Post request to notify subscriber. In case if for any reason notification is not sent successfully
+        after maximum number of reties, then notification is dropped.
+        :param session: An aiohttp client session object to maintain http session.
+        :param notification: A dictionary containing all necessary data to make POST request.
+        :param loop: Event loop object.
+        :param retry_count: An integer specifying the maximum number of reties for a notification.
+        :param timeout: A float representing client timeout of each HTTP request.
+        """
+        backoff_delay = 1
+        while retry_count > 0:
+            try:
+                async with session.post(url=notification["CallbackUri"], headers=notification["headers"],
+                                        auth=notification["auth_basic"], data=json.dumps(notification["payload"]),
+                                        timeout=timeout) as resp:
+                    # self.logger.debug("Notification response: {}".format(resp.status))
+                    if resp.status == HTTPStatus.NO_CONTENT:
+                        self.logger.debug("Notification sent successfully to subscriber {}"
+                                          .format(notification["payload"]["subscriptionId"]))
+                    else:
+                        error_text = "Erroneous response code: {}, ".format(resp.status)
+                        error_text += await resp.text()
+                        raise NotificationException(error_text)
+                return True
+            except Exception as e:
+                error_text = type(e).__name__ + ": " + str(e)
+                self.logger.debug("Unable while sending notification to subscriber {}. Details: {}"
+                                  .format(notification["payload"]["subscriptionId"], error_text))
+                error_detail = {
+                    "error": type(e).__name__,
+                    "error_text": str(e),
+                    "timestamp": time.time()
+                }
+                if "error_details" in notification["payload"].keys():
+                    notification["payload"]["error_details"].append(error_detail)
+                else:
+                    notification["payload"]["error_details"] = [error_detail]
+                retry_count -= 1
+                backoff_delay *= 2
+                self.logger.debug("Retry Notification for subscriber: {} after backoff delay: {} seconds."
+                                  .format(notification["payload"]["subscriptionId"], backoff_delay))
+                await asyncio.sleep(backoff_delay, loop=loop)
+        # Dropping notification
+        self.logger.debug("Notification {} sent failed to subscriber:{}."
+                          .format(notification["payload"]["notificationType"],
+                                  notification["payload"]["subscriptionId"]))
+        return False
+
+
+class NsLcmNotification(NotificationBase):
+
+    # SOL005 response model for nslcm notifications
+    response_models = {
+        "NsLcmOperationOccurrenceNotification": {"id", "nsInstanceId", "nsLcmOpOccId", "operation",
+                                                 "notificationType", "subscriptionId", "timestamp",
+                                                 "notificationStatus", "operationState", "isAutomaticInvocation",
+                                                 "affectedVnf", "affectedVl", "affectedVnffg", "affectedNs",
+                                                 "affectedSap", "error", "_links"},
+
+        "NsIdentifierCreationNotification": {"notificationType", "subscriptionId", "timestamp",
+                                             "nsInstanceId", "_links"},
+
+        "NsIdentifierDeletionNotification": {"notificationType", "subscriptionId", "timestamp",
+                                             "nsInstanceId", "_links"},
+
+        "NsChangeNotification": {"nsInstanceId", "nsComponentType", "nsComponentId",
+                                 "lcmOpOccIdImpactngNsComponent", "lcmOpNameImpactingNsComponent",
+                                 "lcmOpOccStatusImpactingNsComponent", "notificationType", "subscriptionId",
+                                 "timeStamp", "error", "_links"}
+    }
+
+    def __init__(self, db) -> None:
+        """
+        Constructor of NotificationBase class.
+        :param db: Database handler.
+        """
+        super().__init__(db)
+        self.subscriber_collection = "mapped_subscriptions"
+
+    def get_models(self) -> dict:
+        """
+        Returns the SOL005 model of notification class
+        :param None
+        :return: dict of SOL005 data model
+        """
+        return NsLcmNotification.response_models
+
+    @staticmethod
+    def _format_nslcm_subscribers(subscribers: list, event_details: dict) -> list:
+        """
+        Formats the raw event details from kakfa message and subscriber details.
+        :param subscribers: A list of subscribers whom the event needs to be notified.
+        :param event_details: A dict containing all meta data of event.
+        :return:
+        """
+        notification_id = str(uuid4())
+        event_timestamp = event_details["params"]["startTime"]
+        resource_links = event_details["params"]["links"]
+        event_operation = event_details["command"]
+        for key in ["_admin", "_id", "id", "links"]:
+            event_details["params"].pop(key, None)
+        for subscriber in subscribers:
+            subscriber["id"] = notification_id
+            subscriber["timestamp"] = event_timestamp
+            subscriber["_links"] = resource_links
+            subscriber["subscriptionId"] = subscriber["reference"]
+            subscriber["operation"] = event_operation
+            del subscriber["reference"]
+            del subscriber["_id"]
+            subscriber.update(event_details["params"])
+        return subscribers
+
+    def get_subscribers(self, nsd_id: str, ns_instance_id: str, command: str, op_state: str,
+                        event_details: dict) -> list:
+        """
+        Queries database and returns list of subscribers.
+        :param nsd_id: NSD id of an NS whose lifecycle has changed. (scaled, terminated. etc)
+        :param ns_instance_id: NS instance id an NS whose lifecycle has changed.
+        :param command: the command for event.
+        :param op_state: the operation state of NS.
+        :param event_details: dict containing raw data of event occured.
+        :return: List of interested subscribers for occurred event.
+        """
+        filter_q = {"identifier": [nsd_id, ns_instance_id], "operationStates": ["ANY"], "operationTypes": ["ANY"]}
+        if op_state:
+            filter_q["operationStates"].append(op_state)
+        if command:
+            filter_q["operationTypes"].append(command)
+        # self.logger.debug("Db query is: {}".format(filter_q))
+        subscribers = []
+        try:
+            subscribers = self.db.get_list(self.subscriber_collection, filter_q)
+            subscribers = self._format_nslcm_subscribers(subscribers, event_details)
+        except Exception as e:
+            error_text = type(e).__name__ + ": " + str(e)
+            self.logger.debug("Error getting nslcm subscribers: {}".format(error_text))
+        finally:
+            return subscribers
+
+
+class NsdNotification(NotificationBase):
+
+    def __init__(self, db):
+        """
+        Constructor of the class
+        """
+        super().__init__(db)
+        # TODO will update this once support is there from subscription
+        self.response_models = {}
+        self.subscriber_collection = None
+
+
+class VnfdNotification(NotificationBase):
+
+    def __init__(self, db):
+        """
+        Constructor of the class
+        """
+        super().__init__(db)
+        # TODO will update this once support is there from subscription
+        self.response_models = {}
+        self.subscriber_collection = None