def read(self, topic, blocks=True):
"""
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
:param blocks: indicates if it should wait and block until a message is present or returns None
:return: topic, key, message; or None if blocks==True
"""
try:
if isinstance(topic, (list, tuple)):
topic_list = topic
else:
topic_list = (topic, )
while True:
for single_topic in topic_list:
if single_topic not in self.files:
self.files[single_topic] = open(
self.path + single_topic, "a+")
self.buffer[single_topic] = ""
self.buffer[single_topic] += self.files[
single_topic].readline()
if not self.buffer[single_topic].endswith("\n"):
continue
msg_dict = yaml.load(self.buffer[single_topic])
self.buffer[single_topic] = ""
assert len(msg_dict) == 1
for k, v in msg_dict.items():
return single_topic, k, v
if not blocks:
return None
sleep(2)
except Exception as e: # TODO refine
raise MsgException(str(e))
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
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:
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()
def read(self, topic):
#self.topic_lst.append(topic)
try:
return self.loop.run_until_complete(self.aioread(topic))
except Exception as e:
raise MsgException("Error reading {} topic: {}".format(
topic, 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),
loop=self.loop))
except Exception as e:
raise MsgException("Error writing {} topic: {}".format(
topic, str(e)))
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.loop = asyncio.get_event_loop()
self.broker = str(self.host) + ":" + str(self.port)
except Exception as e: # TODO refine
raise MsgException(str(e))
def connect(self, config):
try:
if "logger_name" in config:
self.logger = logging.getLogger(config["logger_name"])
self.path = config["path"]
if not self.path.endswith("/"):
self.path += "/"
if not os.path.exists(self.path):
os.mkdir(self.path)
except MsgException:
raise
except Exception as e: # TODO refine
raise MsgException(str(e))
def read(self, 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, self.loop))
except MsgException:
raise
except Exception as e:
raise MsgException("Error reading {} topic: {}".format(
topic, str(e)))
async def aioread(self, topic, loop=None):
if not loop:
loop = self.loop
self.consumer = AIOKafkaConsumer(loop=loop,
bootstrap_servers=self.broker)
await self.consumer.start()
self.consumer.subscribe([topic])
try:
async for message in self.consumer:
return yaml.load(message.key), yaml.load(message.value)
except KafkaError as e:
raise MsgException(str(e))
finally:
await self.consumer.stop()
def write(self, topic, key, msg):
"""
Insert a message into topic
:param topic: topic
:param key: key text to be inserted
:param msg: value object to be inserted
:return: None or raises and exception
"""
try:
if topic not in self.files:
self.files[topic] = open(self.path + topic, "a+")
yaml.safe_dump({key: msg}, self.files[topic], default_flow_style=True)
self.files[topic].flush()
except Exception as e: # TODO refine
raise MsgException(str(e))
async def aiowrite(self, topic, key, msg, loop=None):
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)
except Exception as e:
raise MsgException("Error publishing to {} topic: {}".format(
topic, str(e)))
finally:
await self.producer.stop()
async def aioread(self, topic, loop):
"""
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
:return: topic, key, message
"""
try:
while True:
msg = self.read(topic, blocks=False)
if msg:
return msg
await asyncio.sleep(2, loop=loop)
except MsgException:
raise
except Exception as e: # TODO refine
raise MsgException(str(e))
def read(self, topic):
try:
msg = ""
if topic not in self.files:
self.files[topic] = open(self.path + topic, "a+")
# ignore previous content
for line in self.files[topic]:
if not line.endswith("\n"):
msg = line
msg += self.files[topic].readline()
if not msg.endswith("\n"):
return None
msg_dict = yaml.load(msg)
assert len(msg_dict) == 1
for k, v in msg_dict.items():
return k, v
except Exception as e: # TODO refine
raise MsgException(str(e))
async def aiowrite(self, topic, key, msg, loop=None):
if not loop:
loop = self.loop
try:
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=yaml.safe_dump(
msg, default_flow_style=True))
except Exception as e:
raise MsgException(
"Error publishing topic '{}', key '{}': {}".format(
topic, key, e))
finally:
await self.producer.stop()
async def aioread(self, topic, loop=None):
try:
msg = ""
if not loop:
loop = asyncio.get_event_loop()
if topic not in self.files:
self.files[topic] = open(self.path + topic, "a+")
# ignore previous content
for line in self.files[topic]:
if not line.endswith("\n"):
msg = line
while True:
msg += self.files[topic].readline()
if msg.endswith("\n"):
break
await asyncio.sleep(2, loop=loop)
msg_dict = yaml.load(msg)
assert len(msg_dict) == 1
for k, v in msg_dict.items():
return k, v
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))