spring-kafka consumer batch error handling with spring boot version 2.3.7 - spring-boot

Question

I am trying to perform the spring kafka batch process error handling. First of all i have few questions.
what is difference between listener and container error handlers and what errors comes into these two categories ?
Could you please help some samples on this to understand better ?
Here is our design:
Poll every certain interval
consume messages in a batch mode
push to local cache (application cache) based on key (to avoid duplicate events)
push all values one by one to another topic once batch process done.
clear the the cache once the operation 3 done and acknowledge the offsets manually.
Here is my plan to have error handling:
public ConcurrentKafkaListenerContainerFactory<String, String> myListenerPartitionContainerFactory(String groupId) {
ConcurrentKafkaListenerContainerFactory<String, String> factory = new ConcurrentKafkaListenerContainerFactory<>();
factory.setConsumerFactory(consumerFactory(groupId));
factory.setConcurrency(partionCount);
factory.getContainerProperties().setAckMode(ContainerProperties.AckMode.MANUAL);
factory.getContainerProperties().setIdleBetweenPolls(pollInterval);
factory.setBatchListener(true);
return factory;
}
#Bean
public ConcurrentKafkaListenerContainerFactory<String, String> myPartitionsListenerContainerFactory()
{
return myListenerPartitionContainerFactory(groupIdPO);
}
#Bean
public RecoveringBatchErrorHandler(KafkaTemplate<String, String> errorKafkaTemplate) {
DeadLetterPublishingRecoverer recoverer =
new DeadLetterPublishingRecoverer(errorKakfaTemplate);
RecoveringBatchErrorHandler errorHandler =
new RecoveringBatchErrorHandler(recoverer, new FixedBackOff(2L, 5000)); // push error event to the error topic
}
#KafkaListener(id = "mylistener", topics = "someTopic", containerFactory = "myPartitionsListenerContainerFactory"))
public void listen(List<ConsumerRecord<String, String>> records, #Header(KafkaHeaders.MESSAGE_KEY) String key, Acknowledgement ack) {
Map hashmap = new Hashmap<>();
records.forEach(record -> {
try {
//key will be formed based on the input record - it will be id.
hashmap.put(key, record);
}
catch (Exception e) {
throw new BatchListenerFailedException("Failed to process", record);
}
});
// Once success each messages to another topic.
try {
hashmap.forEach( (key,value) -> { push to another topic })
hashmap.clear();
ack.acknowledge();
} catch(Exception ex) {
//handle producer exceptions
}
}
is the direction good or any improvements needs to be done? And also what type of container and listener handlers need to be implemented?
#Gary Russell.. could you please help on this ?

Answer 1

The listener error handler is intended for request/reply situations where the error handler can return a meaningful reply to the sender.
You need to throw an exception to trigger the container error handler and you need to know in the index in the original batch to tell it which record failed.
If you are using manual acks like that, you can use the nack() method to indicate which record failed (and don't throw an exception in that case).