Client Configuration
- Client addressing method
  - Client configuration
ClientConfig configuration
DefaultMQProducer configuration
DefaultMQPushConsumer configuration
DefaultLitePullConsumer configuration

Client Configuration

In the RocketMQ Broker cluster, both producers and consumers are clients. This section mainly describes the common behavior configurations for producers and consumers.

Client addressing method

RocketMQ allows clients to find the Name Server, and then find the Broker through the Name Server. There are multiple configuration methods, with priority from high to low, and higher priority will override lower priority.

Specifying the Name Server address in the code, with multiple namesrv addresses separated by semicolons

producer.setNamesrvAddr("192.168.0.1:9876;192.168.0.2:9876");  
consumer.setNamesrvAddr("192.168.0.1:9876;192.168.0.2:9876");

Specifying the Name Server address in the Java startup parameters
```
-Drocketmq.namesrv.addr=192.168.0.1:9876;192.168.0.2:9876
```
Specifying the Name Server address in the environment variable
```
export   NAMESRV_ADDR=192.168.0.1:9876;192.168.0.2:9876
```
HTTP static server addressing (default)

After the client starts, it will periodically access a static HTTP server with the following address: ：http://jmenv.tbsite.net:8080/rocketmq/nsaddr，and the return content of this URL is as follows：
```
192.168.0.1:9876;192.168.0.2:9876
```

The client defaults to accessing this HTTP server every 2 minutes and updating the local Name Server address. The URL is hard-coded in the code, and can be changed by modifying the /etc/hosts file. For example, adding the following configuration in /etc/hosts:

10.232.22.67    jmenv.taobao.net

It is recommended to use the HTTP static server addressing method, as it is simple to deploy the client and the Name Server cluster can be hot upgraded.

Client configuration

DefaultMQProducer, TransactionMQProducer, DefaultMQPushConsumer, and DefaultMQPullConsumer all extends from the ClientConfig class, which is a common configuration class for clients. The client’s configuration is in the form of get and set methods, and each parameter can be configured with Spring or in the code. For example, the namesrvAddr parameter can be configured like this: producer.setNamesrvAddr(“192.168.0.1:9876”), and other parameters are similar.

ClientConfig configuration

Name	Description	Parameter type	Default value
namesrvAddr	NameServer address	String	From -D system parameter rocketmq.namesrv.addr or environment variable.NAMESRV_ADDR
instanceName	Client instance name	String	From -D system parameter rocketmq.client.name, otherwise it is DEFAULT
clientIP	Client IP	String	RemotingUtil.getLocalAddress()
namespace	Client namespace	String
accessChannel	Setting up access channels	AccessChannel	LOCAL
clientCallbackExecutorThreads	The number of processor cores when the client communication layer receives a network request	int	Runtime.getRuntime().availableProcessors()
pollNameServerInterval	Time interval for polling route information from NameServer	int	30000, in milliseconds
heartbeatBrokerInterval	Interval for regularly sending registration heartbeats to broker	int	30000, in milliseconds
persistConsumerOffsetInterval	Applies to Consumer, the interval for persisting consumption progress	int	5000, in milliseconds
pullTimeDelayMillsWhenException	Delay time setting when pulling messages encounters an exception	long	1000, in milliseconds
unitName	Unit name	String
unitMode	Unit mode	boolean	false
vipChannelEnabled	Whether to enable vip netty channel for sending messages	boolean	From -D com.rocketmq.sendMessageWithVIPChannel parameter value, if not it is true
useTLS	Whether to use TLS transport.	boolean	From -D system parameter tls.enable, otherwise it is false.
mqClientApiTimeout	Mq client api timeout setting	int	3000, in milliseconds
language	Client implementation language	LanguageCode	LanguageCode.JAVA

DefaultMQProducer configuration

Name	Description	Parameter type	Default Value
producerGroup	The name of the production group, the identifier of a class of Producers	String	DEFAULT_PRODUCER
createTopicKey	When sending a message, if the topic is not found, if you want to automatically create the topic, you need a key topic, and this value is the value of the key topic.	String	TopicValidator.AUTO_CREATE_TOPIC_KEY_TOPIC
defaultTopicQueueNums	The default number of queues when creating a topic automatically	int	4
sendMsgTimeout	The default send timeout time	int	3000, in milliseconds
compressMsgBodyOverHowmuc	The threshold for message body compression	int	1024 * 4，4K
retryTimesWhenSendFailed	The number of internal retries for rocketmq if synchronous sending fails	int	2
retryTimesWhenSendAsyncFailed	The number of internal retries for rocketmq if asynchronous sending fails	int	2
retryAnotherBrokerWhenNotStoreOK	If the sending result is not SEND_OK status, whether it should be treated as a failure and retried	boolean	false
maxMessageSize	Client verification, the maximum message body size allowed to be sent	int	1024 1024 4，4M
traceDispatcher	synchronous data transfer interface	TraceDispatcher	null

DefaultMQPushConsumer configuration

Name	Description	Parameter type	Default value
consumerGroup	The name of the consumer group, used to identify a class of consumers	String
messageModel	Consumption mode	MessageModel	MessageModel.CLUSTERINGallocateMessageQueueStrategy
consumeFromWhere	Starting consumption point strategy	ConsumeFromWhere	ConsumeFromWhere.CONSUME_FROM_LAST_OFFSET
consumeTimestamp	When using CONSUME_FROM_LAST_OFFSET, start consuming from which time point	String	Half an hour ago
allocateMessageQueueStrategy	Load balancing strategy algorithm	AllocateMessageQueueStrategy	AllocateMessageQueueAveragely（Modulo average distribution.）
subscription	Subscription relationship	Map<String, String>	{}
messageListener	Message processing listener (callback)	MessageListener	null
offsetStore	Message consumption progress storage	OffsetStore	null
consumeThreadMin	Core size of the consumer thread pool	int	20
consumeThreadMax	Maximum size of the consumer thread pool	int	64
adjustThreadPoolNumsThreshold	Dynamic thread core number consumer accumulation threshold	long	100000
consumeConcurrentlyMaxSpan	In concurrent consumption, the maximum offset span allowed for a single consume queue, which will trigger flow control	int	2000pullInterval
pullThresholdForQueue	Consume queue flow control threshold	int	100
pullInterval	Pulling interval	long	0, in milliseconds
pullThresholdForTopic	Topic-level flow control threshold	int	-1
pullThresholdSizeForTopic	Limit the topic-level cache message size	int	-1
pullBatchSize	Maximum batch size for one pull	int	32
consumeMessageBatchMaxSize	Maximum number of messages for batch consumption	int	1
postSubscriptionWhenPull	Whether to update the subscription relationship each time a pull is made	boolean	false
unitMode	Subscription group unit	boolean	false
maxReconsumeTimes	The maximum number of times a message will be consumed before being delivered to the dead-letter queue if it fails	int	-1
suspendCurrentQueueTimeMillis	The time interval for consuming again if the serial consumption returns ROLLBACK or SUSPEND_CURRENT_QUEUE_A_MOMENT	long	1000
consumeTimeout	The longest timeout time for consumption	long	15, in minutes
awaitTerminationMillisWhenShutdown	The longest wait time for messages when closing the consumer, 0 means no wait.	long	0
traceDispatcher	Asynchronous data transfer interface	TraceDispatcher	null

DefaultLitePullConsumer configuration

Name	Description	Parameter type	Default value
consumerGroup	The name of the consumer group, used to identify a type of consumer	String
brokerSuspendMaxTimeMillis	The maximum time that a connection will be suspended for in long polling by the broker	long	20000, in milliseconds
consumerTimeoutMillisWhenSuspend	The maximum wait time for a response from the broker in long polling by the client	long	30000, in milliseconds
consumerPullTimeoutMillis	The socket timeout for pulling messages	long	10000, in milliseconds
messageModel	The consumption mode	MessageModel	MessageModel.CLUSTERING
messageQueueListener	A listener for changes in the allocation of consume queues in load balancing	MessageQueueListener
offsetStore	The message consumption progress storage	OffsetStore
allocateMessageQueueStrategy	The load balancing strategy algorithm	AllocateMessageQueueStrategy	AllocateMessageQueueAveragely（Modulo average distribution.）
unitMode	The unit of subscription group settings	boolean	false
autoCommit	The setting for automatic commit of offset	boolean	true
pullThreadNums	The number of pull threads set	int	20
MIN_AUTOCOMMIT_INTERVAL_MILLIS	The minimum interval time for committing offset	long	1000, in milliseconds
autoCommitIntervalMillis	The maximum interval time for committing offset	long	5000, in milliseconds
pullBatchSize	The maximum number of messages pulled each time	long	10
pullThresholdForAll	The threshold for flow control of consumed requests	int	10000
consumeMaxSpan	The maximum offset span for consumption	int	2000
pullThresholdForQueue	The queue level flow control threshold	int	1000
pullThresholdSizeForQueue	The queue level limit on cached message size	int	100MiB
pollTimeoutMillis	The polling timeout setting	long	5000, in milliseconds
topicMetadataCheckIntervalMillis	The interval for checking changes in topic metadata	long	30000, in milliseconds
consumeFromWhere	The consumption mode setting	ConsumeFromWhere	ConsumeFromWhere.CONSUME_FROM_LAST_OFFSET
consumeTimestamp	The time for backtracking consumption	String	The default consumption rollback time is half an hour ago.
traceDispatcher	The interface for asynchronous data transmission	TraceDispatcher	null
enableMsgTrace	The flag for message tracing	boolean	false
customizedTraceTopic	The name of the topic for message tracing	String