KafkaTransactions - sending to multiple topics within same transaction

[mapuci]

I have this code:

    @Channel(ChannelName.MEASUREMENT_ENRICHED_OUT)
    @OnOverflow(value = OnOverflow.Strategy.BUFFER, bufferSize = 500)
    KafkaTransactions<TrainPassageMeasurementsVO> txProducer;
    @Channel(ChannelName.ALARM_ENRICHED_OUT)
    MutinyEmitter<AlarmEnrichedUpdateTopicVO> alarmEnrichedEmitter;
    
    ...
    
     return txProducer.withTransactionAndAck(commonEvent, emitter ->
            {
               alarmEnrichedEmitter.sendMessageAndAwait(...)
               emitter.send(...);
               return Uni.createFrom().voidItem();
            });

And I want to send to MEASUREMENT_ENRICHED_OUT and ALARM_ENRICHED_OUT channels within the same kafka transaction.
Is that possible?

Guide tells me it is, but I do not know how :)
https://quarkus.io/guides/kafka#kafka-transactions

[cescoffier]

\CC @ozangunalp

[ozangunalp]

It is the same as the example in the docs, except that you also mention the destination topic :

@ApplicationScoped
public class KafkaTransactionalProducer {

    @Channel("tx-out-example")
    KafkaTransactions<String> txProducer;

    public Uni<Void> emitInTransaction() {
        return txProducer.withTransaction(emitter -> {
            emitter.send(KafkaRecord.of("topic1", 1, "a"));
            emitter.send(KafkaRecord.of("topic2", 2, "b"));
            emitter.send(KafkaRecord.of("topic3", 3, "c"));
            return Uni.createFrom().voidItem();
        });
    }

}

[mapuci]

Thanks!