how to configure two instances of Kafka StreamsBui

问题:

Using spring-boot-2.1.3, spring-kafka-2.2.4, I want to have two streams configurations (e.g. to have different application.id, or connect to different cluster, etc). So I defined the first stream configuration pretty much according to the docs, then added a second one, with a different name, and a second StreamsBuilderFactoryBean (also with a different name):

@Bean(name = KafkaStreamsDefaultConfiguration.DEFAULT_STREAMS_CONFIG_BEAN_NAME)
public KafkaStreamsConfiguration kStreamsConfigs() {
    Map<String, Object> props = new HashMap<>();
    props.put(StreamsConfig.APPLICATION_ID_CONFIG, "myappId1000");
    props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
    //...
    return new KafkaStreamsConfiguration(props);
}

@Bean(name = "myKappConfig")
public KafkaStreamsConfiguration myKafkaAppIdConfiguration() {
    Map<String, Object> props = new HashMap<>();
    props.put(StreamsConfig.APPLICATION_ID_CONFIG, "myappId9999");
    props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
    //...
    return new KafkaStreamsConfiguration(props);
}

@Bean(name = "myKappConfigStreamBuilder")
public StreamsBuilderFactoryBean myAppStreamBuilder(
        @Qualifier("myKappConfig") KafkaStreamsConfiguration myKafkaAppIdConfiguration) {
    return new StreamsBuilderFactoryBean(myKafkaAppIdConfiguration);
}

However, when I try to run the app, I get:

Parameter 0 of method kafkaStreamsFactoryBeanConfigurer in org.springframework.boot.autoconfigure.kafka.KafkaStreamsAnnotationDrivenConfiguration required a single bean, but 2 were found: - &defaultKafkaStreamsBuilder: defined by method 'defaultKafkaStreamsBuilder' in class path resource [org/springframework/kafka/annotation/KafkaStreamsDefaultConfiguration.class] - &myKappConfigStreamBuilder: defined by method 'myAppStreamBuilder' in class path resource [com/teramedica/kafakaex001web/KafkaConfig.class]

because the code in the spring-boot autoconfigure does:

@Bean
public KafkaStreamsFactoryBeanConfigurer kafkaStreamsFactoryBeanConfigurer(
        StreamsBuilderFactoryBean factoryBean) {
    return new KafkaStreamsFactoryBeanConfigurer(this.properties, factoryBean);
}

Short of replacing the KafkaStreamsAnnotationDrivenConfiguration entirely, how do I define more than one StreamsBuilderFactoryBean. Or alternately, how can I change the properties for a given stream?

回答1:

Mark one factory bean with @Primary.