+import logging
+import asyncio
+import yaml
from aiokafka import AIOKafkaConsumer
from aiokafka import AIOKafkaProducer
from aiokafka.errors import KafkaError
from msgbase import MsgBase, MsgException
-import asyncio
-import yaml
#import json
+
class MsgKafka(MsgBase):
- def __init__(self):
+ def __init__(self, logger_name='msg'):
+ self.logger = logging.getLogger(logger_name)
self.host = None
self.port = None
self.consumer = None
self.producer = None
- # create a different file for each topic
- #self.files = {}
def connect(self, config):
try:
+ if "logger_name" in config:
+ self.logger = logging.getLogger(config["logger_name"])
self.host = config["host"]
self.port = config["port"]
- self.topic_lst = []
self.loop = asyncio.get_event_loop()
self.broker = str(self.host) + ":" + str(self.port)
except Exception as e: # TODO refine
raise MsgException(str(e))
+ def disconnect(self):
+ try:
+ self.loop.close()
+ except Exception as e: # TODO refine
+ raise MsgException(str(e))
+
def write(self, topic, key, msg):
try:
- self.loop.run_until_complete(self.aiowrite(topic=topic, key=key, msg=yaml.safe_dump(msg, default_flow_style=True)))
+ self.loop.run_until_complete(self.aiowrite(topic=topic, key=key,
+ msg=yaml.safe_dump(msg, default_flow_style=True),
+ loop=self.loop))
except Exception as e:
raise MsgException("Error writing {} topic: {}".format(topic, str(e)))
def read(self, topic):
- #self.topic_lst.append(topic)
+ """
+ Read from one or several topics. it is non blocking returning None if nothing is available
+ :param topic: can be str: single topic; or str list: several topics
+ :return: topic, key, message; or None
+ """
try:
- return self.loop.run_until_complete(self.aioread(topic))
+ return self.loop.run_until_complete(self.aioread(topic, self.loop))
+ except MsgException:
+ raise
except Exception as e:
raise MsgException("Error reading {} topic: {}".format(topic, str(e)))
async def aiowrite(self, topic, key, msg, loop=None):
+
+ if not loop:
+ loop = self.loop
try:
- if not loop:
- loop = self.loop
self.producer = AIOKafkaProducer(loop=loop, key_serializer=str.encode, value_serializer=str.encode,
bootstrap_servers=self.broker)
await self.producer.start()
- await self.producer.send(topic=topic, key=key, value=msg)
+ await self.producer.send(topic=topic, key=key, value=yaml.safe_dump(msg, default_flow_style=True))
except Exception as e:
- raise MsgException("Error publishing to {} topic: {}".format(topic, str(e)))
+ raise MsgException("Error publishing topic '{}', key '{}': {}".format(topic, key, e))
finally:
await self.producer.stop()
- async def aioread(self, topic, loop=None):
+ async def aioread(self, topic, loop=None, callback=None, *args):
+ """
+ Asyncio read from one or several topics. It blocks
+ :param topic: can be str: single topic; or str list: several topics
+ :param loop: asyncio loop
+ :callback: callback function that will handle the message in kafka bus
+ :*args: optional arguments for callback function
+ :return: topic, key, message
+ """
+
if not loop:
loop = self.loop
- self.consumer = AIOKafkaConsumer(loop=loop, bootstrap_servers=self.broker)
- await self.consumer.start()
- self.consumer.subscribe([topic])
try:
+ if isinstance(topic, (list, tuple)):
+ topic_list = topic
+ else:
+ topic_list = (topic,)
+
+ self.consumer = AIOKafkaConsumer(loop=loop, bootstrap_servers=self.broker)
+ await self.consumer.start()
+ self.consumer.subscribe(topic_list)
+
async for message in self.consumer:
- return yaml.load(message.key), yaml.load(message.value)
+ if callback:
+ callback(message.topic, yaml.load(message.key), yaml.load(message.value), *args)
+ else:
+ return message.topic, yaml.load(message.key), yaml.load(message.value)
except KafkaError as e:
raise MsgException(str(e))
finally:
await self.consumer.stop()
-