src/osm_ngsa/osm_mon/core/message_bus_client.py

   1 #######################################################################################
   2 # Copyright ETSI Contributors and Others.
   3 #
   4 # Licensed under the Apache License, Version 2.0 (the "License");
   5 # you may not use this file except in compliance with the License.
   6 # You may obtain a copy of the License at
   7 #
   8 #    http://www.apache.org/licenses/LICENSE-2.0
   9 #
  10 # Unless required by applicable law or agreed to in writing, software
  11 # distributed under the License is distributed on an "AS IS" BASIS,
  12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  13 # implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16 #######################################################################################
  17 from typing import Callable, List
  18
  19 from osm_common import msgkafka, msglocal
  20 from osm_mon.core.config import Config
  21
  22
  23 class MessageBusClient:
  24     def __init__(self, config: Config):
  25         if config.get("message", "driver") == "local":
  26             self.msg_bus = msglocal.MsgLocal()
  27         elif config.get("message", "driver") == "kafka":
  28             self.msg_bus = msgkafka.MsgKafka()
  29         else:
  30             raise Exception(
  31                 "Unknown message bug driver {}".format(config.get("section", "driver"))
  32             )
  33         self.msg_bus.connect(config.get("message"))
  34
  35     async def aioread(self, topics: List[str], callback: Callable = None, **kwargs):
  36         """
  37         Retrieves messages continuously from bus and executes callback for each message consumed.
  38         :param topics: List of message bus topics to consume from.
  39         :param callback: Async callback function to be called for each message received.
  40         :param kwargs: Keyword arguments to be passed to callback function.
  41         :return: None
  42         """
  43         await self.msg_bus.aioread(topics, aiocallback=callback, **kwargs)
  44
  45     async def aiowrite(self, topic: str, key: str, msg: dict):
  46         """
  47         Writes message to bus.
  48         :param topic: Topic to write to.
  49         :param key: Key to write to.
  50         :param msg: Dictionary containing message to be written.
  51         :return: None
  52         """
  53         await self.msg_bus.aiowrite(topic, key, msg)
  54
  55     async def aioread_once(self, topic: str):
  56         """
  57         Retrieves last message from bus.
  58         :param topic: topic to retrieve message from.
  59         :return: tuple(topic, key, message)
  60         """
  61         result = await self.msg_bus.aioread(topic)
  62         return result