osm_common/msgkafka.py

   1 import logging
   2 import asyncio
   3 import yaml
   4 from aiokafka import AIOKafkaConsumer
   5 from aiokafka import AIOKafkaProducer
   6 from aiokafka.errors import KafkaError
   7 from osm_common.msgbase import MsgBase, MsgException
   8 # import json
   9
  10 __author__ = "Alfonso Tierno <alfonso.tiernosepulveda@telefonica.com>, " \
  11              "Guillermo Calvino <guillermo.calvinosanchez@altran.com>"
  12
  13
  14 class MsgKafka(MsgBase):
  15     def __init__(self, logger_name='msg'):
  16         self.logger = logging.getLogger(logger_name)
  17         self.host = None
  18         self.port = None
  19         self.consumer = None
  20         self.producer = None
  21         self.loop = None
  22         self.broker = None
  23
  24     def connect(self, config):
  25         try:
  26             if "logger_name" in config:
  27                 self.logger = logging.getLogger(config["logger_name"])
  28             self.host = config["host"]
  29             self.port = config["port"]
  30             self.loop = asyncio.get_event_loop()
  31             self.broker = str(self.host) + ":" + str(self.port)
  32
  33         except Exception as e:  # TODO refine
  34             raise MsgException(str(e))
  35
  36     def disconnect(self):
  37         try:
  38             self.loop.close()
  39         except Exception as e:  # TODO refine
  40             raise MsgException(str(e))
  41
  42     def write(self, topic, key, msg):
  43         try:
  44             self.loop.run_until_complete(self.aiowrite(topic=topic, key=key,
  45                                                        msg=yaml.safe_dump(msg, default_flow_style=True),
  46                                                        loop=self.loop))
  47
  48         except Exception as e:
  49             raise MsgException("Error writing {} topic: {}".format(topic, str(e)))
  50
  51     def read(self, topic):
  52         """
  53         Read from one or several topics. it is non blocking returning None if nothing is available
  54         :param topic: can be str: single topic; or str list: several topics
  55         :return: topic, key, message; or None
  56         """
  57         try:
  58             return self.loop.run_until_complete(self.aioread(topic, self.loop))
  59         except MsgException:
  60             raise
  61         except Exception as e:
  62             raise MsgException("Error reading {} topic: {}".format(topic, str(e)))
  63
  64     async def aiowrite(self, topic, key, msg, loop=None):
  65
  66         if not loop:
  67             loop = self.loop
  68         try:
  69             self.producer = AIOKafkaProducer(loop=loop, key_serializer=str.encode, value_serializer=str.encode,
  70                                              bootstrap_servers=self.broker)
  71             await self.producer.start()
  72             await self.producer.send(topic=topic, key=key, value=yaml.safe_dump(msg, default_flow_style=True))
  73         except Exception as e:
  74             raise MsgException("Error publishing topic '{}', key '{}': {}".format(topic, key, e))
  75         finally:
  76             await self.producer.stop()
  77
  78     async def aioread(self, topic, loop=None, callback=None, *args):
  79         """
  80         Asyncio read from one or several topics. It blocks
  81         :param topic: can be str: single topic; or str list: several topics
  82         :param loop: asyncio loop
  83         :callback: callback function that will handle the message in kafka bus
  84         :*args: optional arguments for callback function
  85         :return: topic, key, message
  86         """
  87
  88         if not loop:
  89             loop = self.loop
  90         try:
  91             if isinstance(topic, (list, tuple)):
  92                 topic_list = topic
  93             else:
  94                 topic_list = (topic,)
  95
  96             self.consumer = AIOKafkaConsumer(loop=loop, bootstrap_servers=self.broker)
  97             await self.consumer.start()
  98             self.consumer.subscribe(topic_list)
  99
 100             async for message in self.consumer:
 101                 if callback:
 102                     callback(message.topic, yaml.load(message.key), yaml.load(message.value), *args)
 103                 else:
 104                     return message.topic, yaml.load(message.key), yaml.load(message.value)
 105         except KafkaError as e:
 106             raise MsgException(str(e))
 107         finally:
 108             await self.consumer.stop()