osm_common/msgkafka.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 import logging
  17 import asyncio
  18 import yaml
  19 from aiokafka import AIOKafkaConsumer
  20 from aiokafka import AIOKafkaProducer
  21 from aiokafka.errors import KafkaError
  22 from osm_common.msgbase import MsgBase, MsgException
  23
  24 __author__ = "Alfonso Tierno <alfonso.tiernosepulveda@telefonica.com>, " \
  25              "Guillermo Calvino <guillermo.calvinosanchez@altran.com>"
  26
  27
  28 class MsgKafka(MsgBase):
  29     def __init__(self, logger_name='msg', lock=False):
  30         super().__init__(logger_name, lock)
  31         self.host = None
  32         self.port = None
  33         self.consumer = None
  34         self.producer = None
  35         self.loop = None
  36         self.broker = None
  37         self.group_id = None
  38
  39     def connect(self, config):
  40         try:
  41             if "logger_name" in config:
  42                 self.logger = logging.getLogger(config["logger_name"])
  43             self.host = config["host"]
  44             self.port = config["port"]
  45             self.loop = config.get("loop") or asyncio.get_event_loop()
  46             self.broker = str(self.host) + ":" + str(self.port)
  47             self.group_id = config.get("group_id")
  48
  49         except Exception as e:  # TODO refine
  50             raise MsgException(str(e))
  51
  52     def disconnect(self):
  53         try:
  54             pass
  55             # self.loop.close()
  56         except Exception as e:  # TODO refine
  57             raise MsgException(str(e))
  58
  59     def write(self, topic, key, msg):
  60         """
  61         Write a message at kafka bus
  62         :param topic: message topic, must be string
  63         :param key: message key, must be string
  64         :param msg: message content, can be string or dictionary
  65         :return: None or raises MsgException on failing
  66         """
  67         retry = 2   # Try two times
  68         while retry:
  69             try:
  70                 self.loop.run_until_complete(self.aiowrite(topic=topic, key=key, msg=msg))
  71                 break
  72             except Exception as e:
  73                 retry -= 1
  74                 if retry == 0:
  75                     raise MsgException("Error writing {} topic: {}".format(topic, str(e)))
  76
  77     def read(self, topic):
  78         """
  79         Read from one or several topics.
  80         :param topic: can be str: single topic; or str list: several topics
  81         :return: topic, key, message; or None
  82         """
  83         try:
  84             return self.loop.run_until_complete(self.aioread(topic, self.loop))
  85         except MsgException:
  86             raise
  87         except Exception as e:
  88             raise MsgException("Error reading {} topic: {}".format(topic, str(e)))
  89
  90     async def aiowrite(self, topic, key, msg, loop=None):
  91         """
  92         Asyncio write
  93         :param topic: str kafka topic
  94         :param key: str kafka key
  95         :param msg: str or dictionary  kafka message
  96         :param loop: asyncio loop. To be DEPRECATED! in near future!!!  loop must be provided inside config at connect
  97         :return: None
  98         """
  99
 100         if not loop:
 101             loop = self.loop
 102         try:
 103             self.producer = AIOKafkaProducer(loop=loop, key_serializer=str.encode, value_serializer=str.encode,
 104                                              bootstrap_servers=self.broker)
 105             await self.producer.start()
 106             await self.producer.send(topic=topic, key=key, value=yaml.safe_dump(msg, default_flow_style=True))
 107         except Exception as e:
 108             raise MsgException("Error publishing topic '{}', key '{}': {}".format(topic, key, e))
 109         finally:
 110             await self.producer.stop()
 111
 112     async def aioread(self, topic, loop=None, callback=None, aiocallback=None, group_id=None, **kwargs):
 113         """
 114         Asyncio read from one or several topics.
 115         :param topic: can be str: single topic; or str list: several topics
 116         :param loop: asyncio loop. To be DEPRECATED! in near future!!!  loop must be provided inside config at connect
 117         :param callback: synchronous callback function that will handle the message in kafka bus
 118         :param aiocallback: async callback function that will handle the message in kafka bus
 119         :param group_id: kafka group_id to use. Can be False (set group_id to None), None (use general group_id provided
 120                          at connect inside config), or a group_id string
 121         :param kwargs: optional keyword arguments for callback function
 122         :return: If no callback defined, it returns (topic, key, message)
 123         """
 124
 125         if not loop:
 126             loop = self.loop
 127         if group_id is False:
 128             group_id = None
 129         elif group_id is None:
 130             group_id = self.group_id
 131         try:
 132             if isinstance(topic, (list, tuple)):
 133                 topic_list = topic
 134             else:
 135                 topic_list = (topic,)
 136
 137             self.consumer = AIOKafkaConsumer(loop=loop, bootstrap_servers=self.broker, group_id=group_id)
 138             await self.consumer.start()
 139             self.consumer.subscribe(topic_list)
 140
 141             async for message in self.consumer:
 142                 if callback:
 143                     callback(message.topic, yaml.safe_load(message.key), yaml.safe_load(message.value), **kwargs)
 144                 elif aiocallback:
 145                     await aiocallback(message.topic, yaml.safe_load(message.key), yaml.safe_load(message.value),
 146                                       **kwargs)
 147                 else:
 148                     return message.topic, yaml.safe_load(message.key), yaml.safe_load(message.value)
 149         except KafkaError as e:
 150             raise MsgException(str(e))
 151         finally:
 152             await self.consumer.stop()