KafkaPublisher should not be needed when you only want a fetcher.

[gklijs]

Enhancement Description

With additional configuration it should be possible to have a fetcher, consuming events from Kafka, without needing to configure a KafkaPublisher instance.

Current Behaviour

As KafkaPublisher is conditional, the KafkaAutoConfiguration won't do anything when it's not there.

Wanted Behaviour

Being able to have auto configuration when only using the fetcher.

Possible Workarounds

Either don't use auto configuration, or adding a KafkaPublisher (which will not be used).

Possible Solutions

It seems just removing @ConditionalOnClass(KafkaPublisher.class) will fix the issue. As there is already a kafkaPublisher defined inside I don't understand why it's in there. It seems like there is no good reason anymore.