存储Kafka消息[Python版]

前段时间，由于业务需要对Kafka消息从两方面进行存储，一方面离线分批存储，另一方面在线分布式存储。在存储Kafka消息前，需要了解Kafka工作原理。

1 离线分批存储

将消费到的Kafka数据打包分批存储到本地

from pykafka import KafkaClient
import json
import time

client = KafkaClient(hosts="xx.xx.xx.xx:9092,xx.xx.xx.xx:9092,xx.xx.xx.xx:9092")
topic = client.topics['test']
consumer = topic.get_simple_consumer(
    consumer_group="logGroup",
    reset_offset_on_start=True
)

review_list = []

while True:
    for message in consumer:
        if message is not None:
            #print(message.offset, message.value)
            #print(message.value)
            #print(type(message.value)) #<class 'bytes'>
            message.value = str(message.value).strip('b').strip("'")
            print(type(message.value)) #<class 'str'>
            message.value = message.value.replace("\\n", "") #去除\n

            message.value = eval(message.value)
            print(type(message.value)) #<class 'dict'>

            print(message.value)            
            review_list.append(message.value)
            #print(review_list)
            if len(review_list) == 20000:
                now = time.strftime("%Y_%m_%d-%H_%M_%S",time.localtime(time.time()))
                print(now)
                fname="/lujing"+now+r".json"
                with open(fname, 'w') as f:
                    
                    json.dump(review_list, f)
                
                review_list = []
                print(len(review_list)==20000)
                now = time.strftime("%Y_%m_%d-%H_%M_%S",time.localtime(time.time()))
                print(now)

                continue

2 在线分布式存储

直接将消费到的Kafka消息写入HBase

# -*- coding: utf-8 -*-
"""
Created on Tue Nov 5 14:12:09 2019

@author: yoyoyo
"""


from kafka import KafkaConsumer
import happybase
import json
import time

hbase_ip='localhost'
hbase_port=9090
ip = hbase_ip
port = hbase_port
pool = happybase.ConnectionPool(size=1, host=ip) # create connection

# table insert data
def hbase_load(tableName, lists):
    with pool.connection() as connection:
        connection.open()    #start transport
    if tableName not in str(connection.tables()):
        create_table(connection, tableName)
    table = connection.table(tableName)
    b = table.batch(batch_size=1024) # batchs inserts data
    for li in lists:
        try:
            rowkey = li['xxx']
            data_dicts = {}
            for d, x in li.items():
                key = "timeStamp:" + d
                value = str(x)
                data_dicts[key] = value
                b.put(row=rowkey, data=data_dicts)
                b.send()
                print("rowkey:" + rowkey + " data append success")
        except Exception as ex:
            print(str(ex) + " data append failure.")
    connection.close()

# create table
def create_table(conn, table):
    try:
        conn.create_table(
            table,
            {
                "timeStamp": dict(max_versions=10)
            }
        )
    except Exception as ex:
        print(str(ex) + " table exists.")
# print log
def log(str):
    t = time.strftime(r"%Y-%m-%d %H:%M:%S", time.localtime())
    print("[%s]%s" % (t, str))
lst = []
log('start consumer')
consumer = KafkaConsumer('test', group_id='logGroup', bootstrap_servers=['xx.xx.xx.xx:9092']) # HBase集群master ip
for msg in consumer:
    recv = "%s:%d:%d: key=%s value=%s" % (msg.topic, msg.partition, msg.offset, msg.key, msg.value)
    log(recv)
    dict_data = json.loads(msg.value, strict = False)
    dict_data['xxx'] = str(dict_data['xxx'])+'-'+dict_data['xxx']
    lst.append(dict_data)
    hbase_load('kafka2Hbase_test', lst)

服务器调试在线分布式存储时报错处理

错误1 连接Hbase出现的错误

thriftpy2.transport.TTransportException: TTransportException(type=1, message=“Could not connect to (‘localhost’, 9090)”

原因分析
Hbase是用Java写的，原生地提供了Java接口，如果用其他语言，需要开启连接原生提供的thrift接口服务器。也就是python使用HappyBase操作HBase需要先开启thrift接口服务器。

解决办法并查看进程

(base) root@master:/opt/hbase/hbase-1.2.10/bin# hbase-daemon.sh start thrift2

(base) root@master:~# jps
3266 QuorumPeerMain
4772 HMaster
996 Kafka
4102 ResourceManager
4231 NodeManager
11850 ThriftServer
12048 Jps
3890 SecondaryNameNode
3703 DataNode
3578 NameNode

错误2 loads时报错
JSONDecodeError: invalid control character
解决办法：json.loads(json, strict=False) #关掉strict即可