Python3学习（二十二）：Python KafkaProducer and KafkaConsumer的开发模块

1. 在python中往kakfa写数据和读取数据,使用的是python-kafka库
2. 消费者需持续写入数据，因groupid存在偏移量，才能看看到数据。
3. 安装库的命令为pip install python-kafka -i https://pypi.douban.com/simple
4. 其中返回的message为一个生成器，其中元素的type为

代码如下：

#!/usr/bin/env python
# -*- coding: utf-8 -*-
from kafka import KafkaProducer
from kafka import KafkaConsumer
from kafka.errors import KafkaError
import json


class Kafka_producer():
    '''
    使用kafka的生产模块
    '''

    def __init__(self, kafkahost,kafkaport, kafkatopic):
        self.kafkaHost = kafkahost
        self.kafkaPort = kafkaport
        self.kafkatopic = kafkatopic
        self.producer = KafkaProducer(bootstrap_servers = '{kafka_host}:{kafka_port}'.format(
            kafka_host=self.kafkaHost,
            kafka_port=self.kafkaPort
            ))

    def sendjsondata(self, params):
        try:
            parmas_message = json.dumps(params)
            producer = self.producer
            producer.send(self.kafkatopic, parmas_message.encode('utf-8'))
            producer.flush()
        except KafkaError as e:
            print e


class Kafka_consumer():
    '''
    使用Kafka—python的消费模块
    '''

    def __init__(self, kafkahost, kafkaport, kafkatopic, groupid):
        self.kafkaHost = kafkahost
        self.kafkaPort = kafkaport
        self.kafkatopic = kafkatopic
        self.groupid = groupid
        self.consumer = KafkaConsumer(self.kafkatopic, group_id = self.groupid,
                                      bootstrap_servers = '{kafka_host}:{kafka_port}'.format(
            kafka_host=self.kafkaHost,
            kafka_port=self.kafkaPort ))

    def consume_data(self):
        try:
            for message in self.consumer:
                # print json.loads(message.value)
                yield message
        except KeyboardInterrupt, e:
            print e


def main():
    '''
    测试consumer和producer
    :return:
    '''
    ##测试生产模块
    #producer = Kafka_producer("127.0.0.1", 9092, "ranktest")
    #for id in range(10):
    #    params = '{abetst}:{null}---'+str(i)
    #    producer.sendjsondata(params)
    ##测试消费模块
    #消费模块的返回格式为ConsumerRecord(topic=u'ranktest', partition=0, offset=202, timestamp=None, 
    #\timestamp_type=None, key=None, value='"{abetst}:{null}---0"', checksum=-1868164195, 
    #\serialized_key_size=-1, serialized_value_size=21)
    consumer = Kafka_consumer('127.0.0.1', 9092, "ranktest", 'test-python-ranktest')
    message = consumer.consume_data()
    for i in message:
        print i.value


if __name__ == '__main__':
    main()