MessageDispatchingException: Dispatcher has no subscribers

Question

Having a simple Spring Cloud Stream setup.

The interface

public interface MyKafkaBinding {

    @Output(PUBLISHER)
    MessageChannel publisher();

    @Input("subscriber")
    SubscribableChannel subscriber();
}

Binding

@EnableBinding(MyKafkaBinding.class)

Listener

@StreamListener(MyKafkaBinding.PUBLISHER)
public void listen(MyEvent message) {
    // handle
}

App properties

spring.cloud.stream.bindings.publisher.destination=my-kafka-topic
spring.cloud.stream.bindings.publisher.producer.header-mode=headers
spring.cloud.stream.bindings.publisher.content-type=application/json

spring.cloud.stream.bindings.subscriber.destination=my-kafka-topic
spring.cloud.stream.bindings.subscriber.consumer.header-mode=headers
spring.cloud.stream.bindings.subscriber.content-type=application/json

It all works fine. Messages sent using the publisher are received.
Now I'm trying to send a message to this topic from another app, using KafkaTemplate:

kafkaTemplate.send(topic, message)

This time an error is thrown on the receiving side:

Caused by: org.springframework.messaging.MessageDeliveryException: Dispatcher has no subscribers for channel 'MyApp.subscriber'.; nested exception is org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers, failedMessage=GenericMessage [payload=com.bax.so.MyEvent@6da11fec, headers={b3=[B@304c5b9f, kafka_offset=10, scst_nativeHeadersPresent=true, kafka_consumer=org.apache.kafka.clients.consumer.KafkaConsumer@742c6888, deliveryAttempt=3, kafka_timestampType=CREATE_TIME, kafka_receivedMessageKey=null, kafka_receivedPartitionId=0, kafka_receivedTopic=my-kafka-topic, kafka_receivedTimestamp=1578085559878, kafka_groupId=my-default-group-id}]
   at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:77)
   at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:453)
   at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:401)
   at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187)
   at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166)
   at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47)
   at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109)
   at org.springframework.integration.endpoint.MessageProducerSupport.sendMessage(MessageProducerSupport.java:205)
   at org.springframework.integration.kafka.inbound.KafkaMessageDrivenChannelAdapter.sendMessageIfAny(KafkaMessageDrivenChannelAdapter.java:369)
   at org.springframework.integration.kafka.inbound.KafkaMessageDrivenChannelAdapter.access$400(KafkaMessageDrivenChannelAdapter.java:74)
   at org.springframework.integration.kafka.inbound.KafkaMessageDrivenChannelAdapter$IntegrationRecordMessageListener.onMessage(KafkaMessageDrivenChannelAdapter.java:431)
   at org.springframework.integration.kafka.inbound.KafkaMessageDrivenChannelAdapter$IntegrationRecordMessageListener.onMessage(KafkaMessageDrivenChannelAdapter.java:402)
   at org.springframework.kafka.listener.adapter.RetryingMessageListenerAdapter.lambda$onMessage$0(RetryingMessageListenerAdapter.java:120)
   at org.springframework.retry.support.RetryTemplate.doExecute(RetryTemplate.java:287)
   at org.springframework.retry.support.RetryTemplate.execute(RetryTemplate.java:211)
   at org.springframework.kafka.listener.adapter.RetryingMessageListenerAdapter.onMessage(RetryingMessageListenerAdapter.java:114)
   at org.springframework.kafka.listener.adapter.RetryingMessageListenerAdapter.onMessage(RetryingMessageListenerAdapter.java:40)
   at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.doInvokeOnMessage(KafkaMessageListenerContainer.java:1592)
   at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.invokeOnMessage(KafkaMessageListenerContainer.java:1575)
   at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.doInvokeRecordListener(KafkaMessageListenerContainer.java:1534)
   ... 8 common frames omitted
Caused by: org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers
   at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:138)
   at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:105)
   at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
   ... 27 common frames omitted

Spring version 5+.
Is this a valid scenario at all, sending messages using KafkaTemplate and expect them to be received by a cloud stream subscriber ?

Yes, it's a valid scenario; something is preventing the binding from being wired up properly. You need to show the binding properties for the subscriber as well. It's best to show all your code and configuration instead of just snippets. — Gary Russell, Jan 04 '20 at 15:40
@GaryRussell Added 2 additional properties. Don't know what else might help. — Bax, Jan 06 '20 at 18:44
You need `spring.cloud.stream.bindings.subscriber.destination=...` and `...consumer...` properties. By default it will be bound to a topic called `subscriber` so the missing properties, per se, are not the problem. — Gary Russell, Jan 06 '20 at 18:51
@GaryRussell Added subscriber props as well. As pointed in the question, messages sent using the publisher are successfully delivered to the subscriber. — Bax, Jan 06 '20 at 19:02

score 4 · Accepted Answer · answered Jan 06 '20 at 19:19

Your @StreamListener is bound to the publisher channel instead of the subscriber channel.

Here is a working example:

@SpringBootApplication
@EnableBinding(MyKafkaBinding.class)
public class So59585815Application {

    public static void main(String[] args) {
        SpringApplication.run(So59585815Application.class, args);
    }

    @Autowired
    private MessageChannel publisher;

    @StreamListener("subscriber")
    public void listen(String in) {
        publisher.send(new GenericMessage<>(in.toUpperCase()));
    }

    @Bean
    public ApplicationRunner runner(KafkaTemplate<byte[], byte[]> template) {
        return args -> {
            template.send("subscriber-topic", "foo".getBytes());
        };
    }

    @KafkaListener(id = "listener", topics = "publisher-topic")
    public void listen(byte[] in) {
        System.out.println(new String(in));
    }

}

interface MyKafkaBinding {

    @Output("publisher")
    MessageChannel publisher();

    @Input("subscriber")
    SubscribableChannel subscriber();

}

and

spring.cloud.stream.bindings.publisher.destination=publisher-topic
spring.cloud.stream.bindings.subscriber.destination=subscriber-topic
spring.cloud.stream.bindings.subscriber.group=myGroup

spring.kafka.consumer.auto-offset-reset=earliest

score 0 · Answer 2 · answered Jul 12 '21 at 08:49

0

The reason for this problem in my project:

my project cannot connect to Kafka

answered Jul 12 '21 at 08:49

取一个好的名字

1,677
14
16

MessageDispatchingException: Dispatcher has no subscribers

The interface

Binding

Listener

App properties

2 Answers2