osm_nbi/subscriptions.py

   1 # -*- coding: utf-8 -*-
   2
   3 # Licensed under the Apache License, Version 2.0 (the "License");
   4 # you may not use this file except in compliance with the License.
   5 # You may obtain a copy of the License at
   6 #
   7 #    http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  12 # implied.
  13 # See the License for the specific language governing permissions and
  14 # limitations under the License.
  15
  16 """
  17 This module implements a thread that reads from kafka bus implementing all the subscriptions.
  18 It is based on asyncio.
  19 To avoid race conditions it uses same engine class as the main module for database changes
  20 For the moment this module only deletes NS instances when they are terminated with the autoremove flag
  21 """
  22
  23 import logging
  24 import threading
  25 import asyncio
  26 from http import HTTPStatus
  27 from osm_common import dbmongo, dbmemory, msglocal, msgkafka
  28 from osm_common.dbbase import DbException
  29 from osm_common.msgbase import MsgException
  30 from engine import EngineException
  31
  32 __author__ = "Alfonso Tierno <alfonso.tiernosepulveda@telefonica.com>"
  33
  34
  35 class SubscriptionException(Exception):
  36
  37     def __init__(self, message, http_code=HTTPStatus.BAD_REQUEST):
  38         self.http_code = http_code
  39         Exception.__init__(self, message)
  40
  41
  42 class SubscriptionThread(threading.Thread):
  43
  44     def __init__(self, config, engine):
  45         """
  46         Constructor of class
  47         :param config: configuration parameters of database and messaging
  48         :param engine: an instance of Engine class, used for deleting instances
  49         """
  50         threading.Thread.__init__(self)
  51         self.to_terminate = False
  52         self.config = config
  53         self.db = None
  54         self.msg = None
  55         self.engine = engine
  56         self.loop = None
  57         self.logger = logging.getLogger("nbi.subscriptions")
  58         self.aiomain_task = None  # asyncio task for receiving kafka bus
  59         self.internal_session = {  # used for a session to the engine methods
  60             "_id": "subscription",
  61             "id": "subscription",
  62             "project_id": "admin",
  63             "admin": True
  64         }
  65
  66     def run(self):
  67         """
  68         Start of the thread
  69         :return: None
  70         """
  71         self.loop = asyncio.new_event_loop()
  72         try:
  73             if not self.db:
  74                 if self.config["database"]["driver"] == "mongo":
  75                     self.db = dbmongo.DbMongo()
  76                     self.db.db_connect(self.config["database"])
  77                 elif self.config["database"]["driver"] == "memory":
  78                     self.db = dbmemory.DbMemory()
  79                     self.db.db_connect(self.config["database"])
  80                 else:
  81                     raise SubscriptionException("Invalid configuration param '{}' at '[database]':'driver'".format(
  82                         self.config["database"]["driver"]))
  83             if not self.msg:
  84                 config_msg = self.config["message"].copy()
  85                 config_msg["loop"] = self.loop
  86                 if config_msg["driver"] == "local":
  87                     self.msg = msglocal.MsgLocal()
  88                     self.msg.connect(config_msg)
  89                 elif config_msg["driver"] == "kafka":
  90                     self.msg = msgkafka.MsgKafka()
  91                     self.msg.connect(config_msg)
  92                 else:
  93                     raise SubscriptionException("Invalid configuration param '{}' at '[message]':'driver'".format(
  94                         config_msg["driver"]))
  95
  96         except (DbException, MsgException) as e:
  97             raise SubscriptionException(str(e), http_code=e.http_code)
  98
  99         self.logger.debug("Starting")
 100         while not self.to_terminate:
 101             try:
 102                 self.aiomain_task = asyncio.ensure_future(self.msg.aioread(("ns", "nsi"), loop=self.loop,
 103                                                                            callback=self._msg_callback),
 104                                                           loop=self.loop)
 105                 self.loop.run_until_complete(self.aiomain_task)
 106             # except asyncio.CancelledError:
 107             #     break  # if cancelled it should end, breaking loop
 108             except Exception as e:
 109                 if not self.to_terminate:
 110                     self.logger.exception("Exception '{}' at messaging read loop".format(e), exc_info=True)
 111
 112         self.logger.debug("Finishing")
 113         self._stop()
 114         self.loop.close()
 115
 116     def _msg_callback(self, topic, command, params):
 117         """
 118         Callback to process a received message from kafka
 119         :param topic:  topic received
 120         :param command:  command received
 121         :param params: rest of parameters
 122         :return: None
 123         """
 124         try:
 125             if topic == "ns":
 126                 if command == "terminated" and params["operationState"] in ("COMPLETED", "PARTIALLY_COMPLETED"):
 127                     self.logger.debug("received ns terminated {}".format(params))
 128                     if params.get("autoremove"):
 129                         self.engine.del_item(self.internal_session, "nsrs", _id=params["nsr_id"])
 130                         self.logger.debug("ns={} deleted from database".format(params["nsr_id"]))
 131                     return
 132             if topic == "nsi":
 133                 if command == "terminated" and params["operationState"] in ("COMPLETED", "PARTIALLY_COMPLETED"):
 134                     self.logger.debug("received nsi terminated {}".format(params))
 135                     if params.get("autoremove"):
 136                         self.engine.del_item(self.internal_session, "nsis", _id=params["nsir_id"])
 137                         self.logger.debug("nsis={} deleted from database".format(params["nsir_id"]))
 138                     return
 139         except (EngineException, DbException, MsgException) as e:
 140             self.logger.error("Error while processing topic={} command={}: {}".format(topic, command, e))
 141         except Exception as e:
 142             self.logger.exception("Exception while processing topic={} command={}: {}".format(topic, command, e),
 143                                   exc_info=True)
 144
 145     def _stop(self):
 146         """
 147         Close all connections
 148         :return: None
 149         """
 150         try:
 151             if self.db:
 152                 self.db.db_disconnect()
 153             if self.msg:
 154                 self.msg.disconnect()
 155         except (DbException, MsgException) as e:
 156             raise SubscriptionException(str(e), http_code=e.http_code)
 157
 158     def terminate(self):
 159         """
 160         This is a threading safe method to terminate this thread. Termination is done asynchronous afterwards,
 161         but not immediately.
 162         :return: None
 163         """
 164         self.to_terminate = True
 165         self.loop.call_soon_threadsafe(self.aiomain_task.cancel)