After some research i found few configuration i can use to handle this.
default.deserialization.exception.handler - from the StreamsConfig
errors.deadletterqueue.topic.name - from the SinkConnector config
I cant seem to find the equivalent valid configuration for a simple consumer
I want to start a simple consumer and have a DLQ handling whether its via just stating the DLQ topic and let kafka produce it ( like in the sink connector) or purely providing my own class that will produce it (like the streams config).
How can i achieve a DLQ with a simple consumer?
EDIT: Another option i figured is simply handling it in my Deserializer class, just catch an exception there and produce it to my DLQ
But it will mean ill need to create a producer in my deserializer class...
Is this the best practice to handle a DLQ from a consumer?
Related
I'm trying to figure out all the possible exceptions i can expect when i produce a message onto Kafka topic. I looked at the apache producer documentation but didn't find much. so, where can i find the consolidated list of possible exception that a producer can cause/throw?
https://kafka.apache.org/0110/javadoc/index.html?org/apache/kafka/clients/producer/KafkaProducer.html
I am trying to implement a retry logic within kafka streams processor topology in the event there was an exception producing to a sink topic.
I am using a custom ProductionExceptionHandler to be able to catch exception that happen on "producer.send" to the sink topic upon context.forward
What criteria should I use to be able resend the message to an alternate sink topic if there was an exception sending to original sink topic. Could this be deduced from type of exception in producer exception handler without compromising the transactional nature of the internal producer in Kafka streams.
If we decide to produce to a dead letter queue from production exception handler in some unrecoverable errors, could this be done within the context of "EOS" guarantee or it has to be a custom producer not known to the topology.
Kafka Streams has not built-in support for dead-letter-queue. Hence, you are "on your own" to implement it.
What criteria should I use to be able resend the message to an alternate sink topic if there was an exception sending to original sink topic.
Not sure what you mean by this? Can you elaborate?
Could this be deduced from type of exception in producer exception handler
Also not sure about this part.
without compromising the transactional nature of the internal producer in Kafka streams.
That is not possible. You have no access to the internal producer.
If we decide to produce to a dead letter queue from production exception handler in some unrecoverable errors, could this be done within the context of "EOS" guarantee or it has to be a custom producer not known to the topology.
You would need to maintain your own producer and thus it's out-of-scope for EOS.
I use a SpringBoot App to produce or consume/listen to Kafka
messages.
I produce a message in the topic and consume/listen to the
specific message by comparing the messageKey and then send the
consumed message for further processing.
I am stuck with what approach will be better suited to my requirement to get specific message i.e. Kafka Listener or Kafka Consumer what ?
KafkaListener is a Spring specific concept that wraps the Kafka Consumer API.
There is no way to get a message by a particular offset given the key. You must calculate the partition, then scan the entire offset
We are using Ktabke for aggregation in kafka, its very basic use and have referred from kafka doc.
I am just trying to investigate that if some message consumption fails while aggregating how we can move such message to error topic or dlq.
I found something similar for KStream but not able to find for KTable and i was not able to simply extends KStream solution to ktable.
Reference for KStream
Handling bad messages using Kafka's Streams API
My use case is very simple for any kind of exception just move to error topic and move on to different message
There is no built in support for what you ask atm (Kafka 2.2), but you need to make sure that your application code does not throw any exceptions. All provided handlers that can be configured, are for exceptions thrown by Kafka Streams runtime. Those handlers are providing, because otherwise the user has no chance at all to react to those exception.
Feel free to create feature request Jira.
How to create new Kafka Producer from existing Consumer with java ?
You can't create a KafkaProducer from a KafkaConsumer instance.
You have to explicitly create a KafkaProducer using the same connection settings as your producer.
Considering the use case you mentioned (copying data from a topic to another), I'd recommend using Kafka Streams. There's actually an example in Kafka that does exactly that: https://github.com/apache/kafka/blob/trunk/streams/examples/src/main/java/org/apache/kafka/streams/examples/pipe/PipeDemo.java
I will recommend to use the Kafka Streams library. It reads data from kafka topics and do some processing and write back to another topics.
That could be simpler approach for you.
https://kafka.apache.org/documentation/streams/
Current limitation is, Source and destination cluster should be same with Kafka Streams.
Otherwise you need to use Processor API to define another destination cluster.
Another approach, is simply define a producer in the consumer program. Wherever your rule matches(based on offset or any conditions), call producer.send() method