ClassCastException on attempt to get bootstrap server from SenderOption/ReceiverOptions about reactor-kafka

[emmanuelsilva]

Hey all, I also came across this class cast exception when using Spring Boot. I opened the merge request #376 to fix it in the library. Let's see how it goes.

[sanderino666]

As a workaround, I did this:

Map<String, Object> props = kafkaProperties.buildProducerProperties(null);

//reactor-kafka 1.3.22 casts the given bootstrap servers arraylist to a string and throws a class cast exception
//https://github.com/reactor/reactor-kafka/issues/374
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, String.join(",", kafkaProperties.getProducer().getBootstrapServers()));

SenderOptions<String, CloudEvent> senderOptions = SenderOptions.create(props);
...

This is an example for the producer side, the same holds for the consumer side.

kafkaProperties is the org.springframework.boot.autoconfigure.kafka.KafkaProperties coming from the Spring Boot Kafka autoconfiguration.

[ajax-osadchuk-r]

As a workaround, I did this:

Map<String, Object> props = kafkaProperties.buildProducerProperties(null);

//reactor-kafka 1.3.22 casts the given bootstrap servers arraylist to a string and throws a class cast exception
//https://github.com/reactor/reactor-kafka/issues/374
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, String.join(",", kafkaProperties.getProducer().getBootstrapServers()));

SenderOptions<String, CloudEvent> senderOptions = SenderOptions.create(props);
...

This is an example for the producer side, the same holds for the consumer side.

kafkaProperties is the org.springframework.boot.autoconfigure.kafka.KafkaProperties coming from the Spring Boot Kafka autoconfiguration.

Yes, a have also used such workaround, it works.