Spring Cloud Stream does not create a queue

问题

I'm trying to configure a simple Spring Cloud Stream application with RabbitMQ. The code I use is mostly taken from spring-cloud-stream-samples. I have an entry point:

@SpringBootApplication
public class DemoApplication {

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

and a simple messages producer from the example:

@EnableBinding(Source.class)
public class SourceModuleDefinition {

    private String format = "yyyy-MM-dd HH:mm:ss";

    @Bean
    @InboundChannelAdapter(value = Source.OUTPUT, poller = @Poller(fixedDelay = "${fixedDelay}", maxMessagesPerPoll = "1"))
    public MessageSource<String> timerMessageSource() {
        return () -> new GenericMessage<>(new SimpleDateFormat(this.format).format(new Date()));
    }

}

Additionally, here is application.yml configuration:

fixedDelay: 5000
spring:
  cloud:
    stream:
      bindings:
        output:
          destination: test

When I run the example, it connects to Rabbit and creates an exchange called test. But my problem is, it doesn't create a queue and binding automatically. I can see traffic going in Rabbit, but all my messages are then gone. While I need them to stay in some queue unless they are read by consumer.

Maybe I misunderstand something, but from all the topics I read, it seems like Spring Cloud Stream should create a queue and a binding automatically. If not, how do I configure it so my messages are persisted?

I'm using Spring Cloud Brixton.SR5 and Spring Boot 1.4.0.RELEASE.

回答1:

A queue would be created as soon as you start a consumer application.

In the case of Rabbit MQ, where we have separate queues for each consumer group and we cannot know all groups beforehand, if you want to have the queues created automatically for consumer groups that are known in advance, you can use the requiredGroups property of the producers. This will ensure that messages are persisted until a consumer from that group is started.

See details here: http://docs.spring.io/spring-cloud-stream/docs/Brooklyn.BUILD-SNAPSHOT/reference/htmlsingle/#_producer_properties

回答2:

You will need a consumer in order to have a queue created.

Here you can find an example of a producer and a consumer using rabbitMq:

http://ignaciosuay.com/how-to-implement-asyncronous-communication-between-microservices-using-spring-cloud-stream/

来源：https://stackoverflow.com/questions/39551875/spring-cloud-stream-does-not-create-a-queue

标签

Spring

spring-cloud-stream