kafka配置文件详解：consumer.properties

consumer作为kafak核心组件之一，学习和分析它是很有必要的。consumer配置文件在kafak的config目录下，配置好它

在以后的学习和工作中都可以起到事半功倍的效果。

# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
# 
#    http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# see kafka.consumer.ConsumerConfig for more details


# Zookeeper connection string
# comma separated host:port pairs, each corresponding to a zk
# server. e.g. "127.0.0.1:3000,127.0.0.1:3001,127.0.0.1:3002"

#(必需)zookeeper连接服务器地址(集群可写多个)
zookeeper.connect=127.0.0.1:2181


# timeout in ms for connecting to zookeeper

#zookeeper的session的过期时间
zookeeper.connection.timeout.ms=6000

#指定多久消费者更新offset到zookeeper中

zookeeper.sync.time.ms=2000 

#consumer group id

#(必需)consumer组id
group.id=test-consumer-group

#consumer timeout
#消费者超时
#consumer.timeout.ms=5000

#自动向zookeeper提交offset信息

auto.commit.enable=true 

#自动更新时间

auto.commit.interval.ms=1000

#当前consumer的标识

#consumer.id=xxx  

#消费者客户端编号，用于区分不同客户端，默认客户端程序自动产生  

#client.id=xxx 

#最大取多少块缓存到消费者（默认10） 

#queued.max.message.chunks=50

#当有新的consumer加入到group时，将会reblance.

#rebalance.max.retries=5

#获取消息的最大尺寸,broker不会向consumer输出大于此值得chunk

#fetch.min.bytes=655360

补充：consumer.properties详细配置说明

属性	默认 值	描述
group.id		Consumer的组ID，相同goup.id的consumer属于同一个组。
zookeeper.connect		Consumer的zookeeper连接串，要和broker的配置一致。
consumer.id	null	如果不设置会自动生成。
socket.timeout.ms	30 * 1000	网络请求的socket超时时间。实际超时时间由max.fetch.wait + socket.timeout.ms 确定。
socket.receive.buffer.bytes	64 * 1024	The socket receive buffer for network requests.
fetch.message.max.bytes	1024 * 1024	查询topic-partition时允许的最大消息大小。consumer会为每个partition缓存此大小的消息到内存，因此，这个参数可以控制consumer的内存使用量。这个值应该至少比server允许的最大消息大小大，以免producer发送的消息大于consumer允许的消息。
num.consumer.fetchers	1	The number fetcher threads used to fetch data.
auto.commit.enable	true	如果此值设置为true，consumer会周期性的把当前消费的offset值保存到zookeeper。当consumer失败重启之后将会使用此值作为新开始消费的值。
auto.commit.interval.ms	60 * 1000	Consumer提交offset值到zookeeper的周期。
queued.max.message.chunks	2	用来被consumer消费的message chunks 数量， 每个chunk可以缓存fetch.message.max.bytes大小的数据量。
rebalance.max.retries	4	When a new consumer joins a consumer group the set of consumers attempt to “rebalance” the load to assign partitions to each consumer. If the set of consumers changes while this assignment is taking place the rebalance will fail and retry. This setting controls the maximum number of attempts before giving up.
fetch.min.bytes	1	The minimum amount of data the server should return for a fetch request. If insufficient data is available the request will wait for that much data to accumulate before answering the request.
fetch.wait.max.ms	100	The maximum amount of time the server will block before answering the fetch request if there isn’t sufficient data to immediately satisfy fetch.min.bytes.
rebalance.backoff.ms	2000	Backoff time between retries during rebalance.
refresh.leader.backoff.ms	200	Backoff time to wait before trying to determine the leader of a partition that has just lost its leader.
auto.offset.reset	largest	What to do when there is no initial offset in ZooKeeper or if an offset is out of range ;smallest : automatically reset the offset to the smallest offset; largest : automatically reset the offset to the largest offset;anything else: throw exception to the consumer
consumer.timeout.ms	-1	若在指定时间内没有消息消费，consumer将会抛出异常。
exclude.internal.topics	true	Whether messages from internal topics (such as offsets) should be exposed to the consumer.
zookeeper.session.timeout.ms	6000	ZooKeeper session timeout. If the consumer fails to heartbeat to ZooKeeper for this period of time it is considered dead and a rebalance will occur.
zookeeper.connection.timeout.ms	6000	The max time that the client waits while establishing a connection to zookeeper.
zookeeper.sync.time.ms	2000	How far a ZK follower can be behind a ZK leader