[FIXED] Filter messages before deserialization based on headers

Issue

Sometimes messages can be filtered out before the deserialization based on header values . Are there any existing patterns for this scenario using spring kafka. I am thinking implementing similar to ErrorHandlingDeserializer in addition to delegate take filter predicate also as property. Any suggestions? thanks.

Solution

Yes, you can use the same technique used by the ErrorHandlingDeserializer to return a "marker" object instead of doing the deserialization, then add a RecordFilterStrategy, that filters records with such objects, to the listener (container factory when using @KafkaListener or use a filtering adapter for an explicit listener).

EDIT

Spring Boot and adding a filter...

    @Bean
    public ConcurrentKafkaListenerContainerFactory<?, ?> kafkaListenerContainerFactory(
            ConcurrentKafkaListenerContainerFactoryConfigurer configurer,
            ConsumerFactory<Object, Object> kafkaConsumerFactory) {
        ConcurrentKafkaListenerContainerFactory<Object, Object> factory = new ConcurrentKafkaListenerContainerFactory<>();
        configurer.configure(factory, kafkaConsumerFactory);
        kafkaConsumerFactory.setRecordFilterStrategy(myFilter());
        return factory;
    }

Answered By - Gary Russell