I've got a spring boot app that defines:
- a REST Controller that writes to a kafka topic, STREAM_TOPIC_IN_QQQ
- a KafkaListener that reads from STREAM_TOPIC_IN_QQQ (groupId="bar") and logs
- a KStream that peeks the topic and logs it, converts it to another type, then writes it to STREAM_TOPIC_OUT_QQQ
- another KafkaListener that reads from STREAM_TOPIC_OUT_QQQ.
(I've been changing the suffix to avoid any possible confusion, and creating the topics by hand, because otherwise I was getting a warning, STREAM_TOPIC_IN_xxx=LEADER_NOT_AVAILABLE and the stream would not run for a minute or so.)
The first listener and the stream seem to be working, but when the listener on the STREAM_OUT_TOPIC tries to deserialize the message, I get the exception below. I am providing the serde in the stream with Produced.with. What do I need to do so that the listener knows the type to deserialize to?
Log
11 Mar 2019 14:34:00,194 DEBUG [KafkaMessageController [] http-nio-8080-exec-1] Sending a Kafka Message
11 Mar 2019 14:34:00,236 INFO [KafkaConfig [] kafka9000-v0.1-b0a60795-0258-48d9-8c87-30fa9a97d7b8-StreamThread-1] -------------- STREAM_IN_TOPIC peek: Got a greeting in the stream: Hello, World!
11 Mar 2019 14:34:00,241 INFO [KafkaConfig [] org.springframework.kafka.KafkaListenerEndpointContainer#1-0-C-1] STREAM_IN_TOPIC Listener: ConsumerRecord: {}ConsumerRecord(topic = STREAM_TOPIC_IN_QQQ, partition = 0, offset = 0, CreateTime = 1552332840188, serialized key size = 1, serialized value size = 34, headers = RecordHeaders(headers = [], isReadOnly = false), key = 1, value = com.teramedica.kafakaex001web.model.Greeting@7b6c8fcc)
11 Mar 2019 14:34:00,243 INFO [Metadata [] kafka-producer-network-thread | kafka9000-v0.1-b0a60795-0258-48d9-8c87-30fa9a97d7b8-StreamThread-1-producer] Cluster ID: y48IEZaGQWKcWDVGf4mD6g
11 Mar 2019 14:34:00,367 ERROR [LoggingErrorHandler [] org.springframework.kafka.KafkaListenerEndpointContainer#0-0-C-1] Error while processing: ConsumerRecord(topic = STREAM_TOPIC_OUT_QQQ, partition = 0, offset = 0, CreateTime = 1552332840188, serialized key size = 1, serialized value size = 48, headers = RecordHeaders(headers = [RecordHeader(key = springDeserializerExceptionValue, value = [ REDACTED ])], isReadOnly = false), key = 1, value = null)
org.springframework.kafka.support.serializer.DeserializationException: failed to deserialize; nested exception is java.lang.IllegalStateException: No type information in headers and no default type provided
at org.springframework.kafka.support.serializer.ErrorHandlingDeserializer2.deserializationException(ErrorHandlingDeserializer2.java:204) ~[spring-kafka-2.2.4.RELEASE.jar:2.2.4.RELEASE]
Here's the configuration:
REST (spring mvc):
@RequestMapping("/greeting")
public Greeting greeting(@RequestParam(value = "name", defaultValue = "World") String name) {
Greeting gr = new Greeting(counter.incrementAndGet(), String.format(msgTemplate, name));
this.kafkaTemplate.send(K9000Consts.STREAM_TOPIC_IN, "1", gr);
logger.debug("Sending a Kafka Message");
return gr;
}
Kafka Config (spring-kafka):
@Bean
public KStream<String, Greeting> kStream(StreamsBuilder kStreamBuilder) {
KStream<String, Greeting> stream = kStreamBuilder.stream(K9000Consts.STREAM_TOPIC_IN);
stream.peek((k, greeting) -> {
logger.info("-------------- STREAM_IN_TOPIC peek: Got a greeting in the stream: {}", greeting.getContent());
})
.map((k, v) -> new KeyValue<>(k, new GreetingResponse(v)))
.to(K9000Consts.STREAM_TOPIC_OUT, Produced.with(stringSerde, new JsonSerde<>(GreetingResponse.class)));
return stream;
}
@KafkaListener(topics = K9000Consts.STREAM_TOPIC_OUT, groupId="oofda", errorHandler = "myTopicErrorHandler")
public void listenForGreetingResponse(ConsumerRecord<String, GreetingResponse> cr) throws Exception {
logger.info("STREAM_OUT_TOPIC Listener : {}" + cr.toString());
}
@KafkaListener(topics = K9000Consts.STREAM_TOPIC_IN, groupId = "bar")
public void listenForGreetingResponses(ConsumerRecord<String, Greeting> cr) throws Exception {
logger.info("STREAM_IN_TOPIC Listener: ConsumerRecord: {}" + cr.toString());
}
application.yml
spring:
kafka:
bootstrap-servers: localhost:9092
consumer:
group-id: foo
auto-offset-reset: latest
key-deserializer: org.springframework.kafka.support.serializer.ErrorHandlingDeserializer2
value-deserializer: org.springframework.kafka.support.serializer.ErrorHandlingDeserializer2
properties:
spring.json.trusted.packages: com.teramedica.kafakaex001web.model
spring.deserializer.key.delegate.class: org.apache.kafka.common.serialization.StringDeserializer
spring.deserializer.value.delegate.class: org.springframework.kafka.support.serializer.JsonDeserializer
producer:
key-serializer: org.apache.kafka.common.serialization.StringSerializer
value-serializer: org.springframework.kafka.support.serializer.JsonSerializer
streams:
application-id: kafka9000-v0.1
properties: # properties not explicitly handled by KafkaProperties.streams
default.key.serde: org.apache.kafka.common.serialization.Serdes$StringSerde
default.value.serde: org.springframework.kafka.support.serializer.JsonSerde
spring.json.trusted.packages: com.teramedica.kafakaex001web.model