Retry Topic Auto configuration - Auto creation of topics

[tomazfernandes]

Hi, I'm looking into doing some work around retry topics auto-configuration with Spring Boot - in particular adding a few lines in the SK docs about it.

One concern I remember @garyrussell raised a while back was that auto creation of topics was disabled for auto-configuration:

@Bean
@ConditionalOnProperty(name = "spring.kafka.retry.topic.enabled")
@ConditionalOnSingleCandidate(KafkaTemplate.class)
public RetryTopicConfiguration kafkaRetryTopicConfiguration(KafkaTemplate<?, ?> kafkaTemplate) {
    KafkaProperties.Retry.Topic retryTopic = this.properties.getRetry().getTopic();
    RetryTopicConfigurationBuilder builder = RetryTopicConfigurationBuilder.newInstance()
        .maxAttempts(retryTopic.getAttempts())
	.useSingleTopicForSameIntervals()
	.suffixTopicsWithIndexValues()
	.doNotAutoCreateRetryTopics();
    setBackOffPolicy(builder, retryTopic);
    return builder.create(kafkaTemplate);
}

I thought of adding an auto-configuration property for allowing users to override this, and opened an issue in boot for that.

But now that I think again, the default behavior for KafkaConsumer is to auto create topics, so I'm thinking this might be a non-issue? I just created a sample app and when using auto-configuration it creates all topics accordingly.

If this looks good enough, I'm thinking I'll just add a few lines to SK docs so users know they can use auto configuration for the feature.

How does that sound?

Thanks!

[garyrussell]

@tomazfernandes The problem with broker-auto-created topics is there is no control over the partitions/replication (at the application level). It can also be disabled at the broker level.

@snicoll reached out to me last week and he said he plans on addressing that Boot issue before the RC next week; we decided to go with your original suggestion (3 properties).

[tomazfernandes]

Cool, thanks @garyrussell! Let me know if there's anything I can help with.