# Copyright (c) 2019, MD2K Center of Excellence
# - Nasir Ali <nasir.ali08@gmail.com>
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import json
from pyspark.streaming import StreamingContext
from kafka import KafkaConsumer
from kafka import KafkaProducer
from cerebralcortex.core.messaging_manager.kafka_handler import KafkaHandler
[docs]class MessagingQueue(KafkaHandler):
def __init__(self, CC: object, auto_offset_reset: str="largest"):
"""
Messaging queue module support pub/sub system in CerebralCortex
Args:
CC (CerebralCortex): cerebralcortex class object
auto_offset_reset (str): smallest (start of the topic) OR largest (end of a topic) (default="largest")
"""
self.config = CC.config
self.CC = CC
if CC.config["messaging_service"]=="none":
raise Exception("Messaging service is disabled (none) in cerebralcortex.yml. Please update configs.")
self.ping_kafka = self.config["kafka"]["ping_kafka"]
self.consumer_group_id = self.config["kafka"]["consumer_group_id"]
try:
ping_kafka = int(self.ping_kafka)
except:
raise Exception("ping_kafka value can only be an integer. Please check data_ingestion.yml")
self.ssc = StreamingContext(self.CC.sparkContext, ping_kafka)
if self.config["messaging_service"]!="none" and "kafka" in self.config and self.config['messaging_service']=="kafka":
self.broker = str(self.config['kafka']['host']) +":"+str(self.config['kafka']['port'])
self.auto_offset_reset= auto_offset_reset
self.producer = KafkaProducer(bootstrap_servers=str(self.broker), api_version=(0,10),
value_serializer=lambda v: json.dumps(v).encode('utf-8'),
compression_type='gzip')
self.consumer = KafkaConsumer(bootstrap_servers=str(self.broker), api_version=(0,10),
auto_offset_reset=self.auto_offset_reset)