cn.leancloud.kafka.consumer

Class CatchAllExceptionConsumerRecordHandler<K,V>

java.lang.Object

cn.leancloud.kafka.consumer.CatchAllExceptionConsumerRecordHandler<K,V>

Type Parameters:

K - the type of key for records consumed from Kafka

V - the type of value for records consumed from Kafka

All Implemented Interfaces:

ConsumerRecordHandler<K,V>

public final class CatchAllExceptionConsumerRecordHandler<K,V>
extends Object
implements ConsumerRecordHandler<K,V>

A wrapper over a ConsumerRecordHandler to catch and swallow all the exceptions throw from the wrapped ConsumerRecordHandler when it failed to handle a consumed record.

This handler seems good to improve the availability of the consumer because it can swallow all the exceptions on handling a record and carry on to handle next record. But it actually can compromise the consumer to prevent a livelock, where the application did not crash but fails to make progress for some reason. Please use it judiciously. Usually fail fast, let the polling thread exit on exception, is your best choice.

Constructor Summary

Constructors

Constructor and Description
CatchAllExceptionConsumerRecordHandler(ConsumerRecordHandler<K,V> wrappedHandler) Constructor for CatchAllExceptionConsumerRecordHandler to just log the failed record when the wrapped handler failed on calling ConsumerRecordHandler.handleRecord(ConsumerRecord).
CatchAllExceptionConsumerRecordHandler(ConsumerRecordHandler<K,V> wrappedHandler, BiConsumer<org.apache.kafka.clients.consumer.ConsumerRecord<K,V>,Throwable> errorConsumer) Constructor for CatchAllExceptionConsumerRecordHandler to use a BiConsumer to handle the failed record when the wrapped handler failed on calling ConsumerRecordHandler.handleRecord(ConsumerRecord).

Method Summary

Modifier and Type	Method and Description
void	handleRecord(org.apache.kafka.clients.consumer.ConsumerRecord<K,V> record) Handle a ConsumerRecord consumed from Kafka broker.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CatchAllExceptionConsumerRecordHandler

public CatchAllExceptionConsumerRecordHandler(ConsumerRecordHandler<K,V> wrappedHandler)

Constructor for CatchAllExceptionConsumerRecordHandler to just log the failed record when the wrapped handler failed on calling ConsumerRecordHandler.handleRecord(ConsumerRecord).

Parameters:

wrappedHandler - the wrapped ConsumerRecordHandler.

CatchAllExceptionConsumerRecordHandler

public CatchAllExceptionConsumerRecordHandler(ConsumerRecordHandler<K,V> wrappedHandler,
                                              BiConsumer<org.apache.kafka.clients.consumer.ConsumerRecord<K,V>,Throwable> errorConsumer)

Constructor for CatchAllExceptionConsumerRecordHandler to use a BiConsumer to handle the failed record when the wrapped handler failed on calling ConsumerRecordHandler.handleRecord(ConsumerRecord).

Parameters:

wrappedHandler - the wrapped ConsumerRecordHandler.

errorConsumer - a BiConsumer to consume the failed record and the exception thrown from the ConsumerRecordHandler.handleRecord(ConsumerRecord)

Method Detail

handleRecord

public void handleRecord(org.apache.kafka.clients.consumer.ConsumerRecord<K,V> record)

Description copied from interface: ConsumerRecordHandler

Handle a ConsumerRecord consumed from Kafka broker.

For the sake of fail fast, if any exception throws from this method, the thread for fetching records from Kafka broker will exit with an error message. This will trigger rebalances of partitions among all the consumer groups this consumer joined and let other consumer try to handle the failed and the following records.

You can consider to use RetriableConsumerRecordHandler to retry handling process automatically. Or use CatchAllExceptionConsumerRecordHandler as a safety net to handle all the failed records in the same way.

Specified by:

handleRecord in interface ConsumerRecordHandler<K,V>

Parameters:

record - the consumed ConsumerRecord