动态主题名称/Quarkus SmallRye Reactive Messaging Kafka

Question

我想使用这个扩展：[Quarkus Smallrye Reactive Messaging Kafka]

但是在我的应用程序中，主题的名称是事先不知道的，它是根据运行时从用户那里收到的消息指定的。 如何在没有注释的情况下以编程方式指定主题名称和与主题相关的设置？ （仅用于向 Kafka -> Produce 发送消息）

@ApplicationScoped
public class PriceGenerator {

    private Random random = new Random();

    // Don't want to use this 
    // "generated-price" not known at build time
    @Outgoing("generated-price")                       
    public Multi<Integer> generate() {                  
        return Multi.createFrom().ticks().every(Duration.ofSeconds(5))
                .onOverflow().drop()
                .map(tick -> random.nextInt(100));
    }

}

或者这些配置应该在运行时以编程方式设置

mp.messaging.outgoing.generated-price.connector=smallrye-kafka
mp.messaging.outgoing.generated-price.topic=prices
mp.messaging.outgoing.generated-price.value.serializer=org.apache.kafka.common.serialization.IntegerSerializer

因为不识路，所以用的是原生的kafka驱动

    <dependency>
      <groupId>io.quarkus</groupId>
      <artifactId>quarkus-kafka-client</artifactId>
    </dependency>

Properties props = new Properties();
props.put("bootstrap.servers", "85.93.89.115:9092");
props.put("acks", "all");
props.put("retries", 0);
props.put("linger.ms", 1);
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
Producer<String, String> producer = new KafkaProducer<>(props);
producer.send(new ProducerRecord<String, String>(topicName.toString(), messageFactory.MessageToString(message)));

Answer 1

您可以在启动时或任何需要的时候动态地覆盖主题的值，但这里有一段代码指示如何覆盖主题的预定义值：

@ApplicationScoped
public class AppLifecycleBean {

    void onStart(@Observes StartupEvent ev) {               
        System.setProperty("mp.messaging.outgoing.generated-price.topic", "example");
    }

    void onStop(@Observes ShutdownEvent ev) {               
    }

}