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'):
  30         self.logger = logging.getLogger(logger_name)
  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 = 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         try:
  68             self.loop.run_until_complete(self.aiowrite(topic=topic, key=key, msg=msg))
  69
  70         except Exception as e:
  71             raise MsgException("Error writing {} topic: {}".format(topic, str(e)))
  72
  73     def read(self, topic):
  74         """
  75         Read from one or several topics.
  76         :param topic: can be str: single topic; or str list: several topics
  77         :return: topic, key, message; or None
  78         """
  79         try:
  80             return self.loop.run_until_complete(self.aioread(topic, self.loop))
  81         except MsgException:
  82             raise
  83         except Exception as e:
  84             raise MsgException("Error reading {} topic: {}".format(topic, str(e)))
  85
  86     async def aiowrite(self, topic, key, msg, loop=None):
  87
  88         if not loop:
  89             loop = self.loop
  90         try:
  91             self.producer = AIOKafkaProducer(loop=loop, key_serializer=str.encode, value_serializer=str.encode,
  92                                              bootstrap_servers=self.broker)
  93             await self.producer.start()
  94             await self.producer.send(topic=topic, key=key, value=yaml.safe_dump(msg, default_flow_style=True))
  95         except Exception as e:
  96             raise MsgException("Error publishing topic '{}', key '{}': {}".format(topic, key, e))
  97         finally:
  98             await self.producer.stop()
  99
 100     async def aioread(self, topic, loop=None, callback=None, aiocallback=None, **kwargs):
 101         """
 102         Asyncio read from one or several topics. It blocks.
 103         :param topic: can be str: single topic; or str list: several topics
 104         :param loop: asyncio loop
 105         :param callback: synchronous callback function that will handle the message in kafka bus
 106         :param aiocallback: async callback function that will handle the message in kafka bus
 107         :param kwargs: optional keyword arguments for callback function
 108         :return: If no callback defined, it returns (topic, key, message)
 109         """
 110
 111         if not loop:
 112             loop = self.loop
 113         try:
 114             if isinstance(topic, (list, tuple)):
 115                 topic_list = topic
 116             else:
 117                 topic_list = (topic,)
 118
 119             self.consumer = AIOKafkaConsumer(loop=loop, bootstrap_servers=self.broker, group_id=self.group_id)
 120             await self.consumer.start()
 121             self.consumer.subscribe(topic_list)
 122
 123             async for message in self.consumer:
 124                 if callback:
 125                     callback(message.topic, yaml.load(message.key), yaml.load(message.value), **kwargs)
 126                 elif aiocallback:
 127                     await aiocallback(message.topic, yaml.load(message.key), yaml.load(message.value), **kwargs)
 128                 else:
 129                     return message.topic, yaml.load(message.key), yaml.load(message.value)
 130         except KafkaError as e:
 131             raise MsgException(str(e))
 132         finally:
 133             await self.consumer.stop()