Spring Boot 2.7.2 with Spring Kafka fails during initialisation with Exception: The 'ProducerFactory' must support transactions`

I’m using Spring Boot v2.7.2 and the latest version of Spring Kafka provided by spring-boot-dependencies:

<dependency>
    <groupId>org.springframework.kafka</groupId>
    <artifactId>spring-kafka</artifactId>
</dependency>

I want the app to load all configuration from application.yaml, hence I created the beans with this bare minimum configuration:

    public class KakfaConfig {

    @Bean
    public ProducerFactory<Integer, FileUploadEvent> producerFactory() {
        return new DefaultKafkaProducerFactory<>(Collections.emptyMap());
    }

    @Bean
    public KafkaTemplate<Integer, FileUploadEvent> kafkaTemplate() {
        return new KafkaTemplate<Integer, anEvent>(producerFactory());
    }

}

It seems to work as expected and loads the configuration from the application.yaml below:

spring:
  application:
    name: my-app
  kafka:
    bootstrap-servers: localhost:9092
    producer:
      client-id: ${spring.application.name}
  #    transaction-id-prefix: "tx-"
    template:
      default-topic: my-topic

However, if I uncomment the transaction-id-prefix line, the application fails to start with the exception java.lang.IllegalArgumentException: The 'ProducerFactory' must support transactions
The documentation in here reads

If you provide a custom producer factory, it must support transactions. See ProducerFactory.transactionCapable().

The only way I have found to make it work is adding the transaction prefix programmatically as shown in the snippet below:

@Bean
public ProducerFactory<Integer, FileUploadEvent> fileUploadProducerFactory() {
    var pf = new DefaultKafkaProducerFactory<Integer, FileUploadEvent>(Collections.emptyMap());
    pf.setTransactionIdPrefix("tx-");
    return pf;
}

Any thoughts on how I can configure everything using application properties file?

[wilkinsona]

AIUI, the intent is that transactions should be used and that the ProducerFactory should support them. The transaction-id-prefix property can be set and this results in the auto-configuration of the kafkaTransactionManager bean. However, if you define your own ProducerFactory (to constrain the types, for example) there’s no built-in way to have the transaction-id-prefix applied to that ProducerFactory.

@dbaltor One option could be to use @Value to inject the transaction ID prefix:

@Bean
public ProducerFactory<Integer, FileUploadEvent> fileUploadProducerFactory(
        @Value("spring.kafka.producer.transaction-id-prefix") String transactionIdPrefix) {
    var pf = new DefaultKafkaProducerFactory<Integer, FileUploadEvent>(Collections.emptyMap());
    pf.setTransactionIdPrefix(transactionIdPrefix);
    return pf;
}

[dbaltor]

That’s very interesting. Thank you @garyrussell ! At this time, I think I do need to create my own beans as I’m using bespoken (De)Serializers in both of my Producer and Consumer factories.