How to create instance specific message queues in springboot rest api

Question

I have a number of microservices, each running in its own container in a load balanced environment. I have a need for each instance of these microservices to create a rabbitmq queue when it starts up and delete it when it stops. I have currently defined the following property in my application properties file:

config_queue: config_${PID}

My message queue listener looks like this:

public class ConfigListener {
    Logger logger = LoggerFactory.getLogger(ConfigListener.class);

    // https://www.programcreek.com/java-api-examples/index.php?api=org.springframework.amqp.rabbit.annotation.RabbitListener
    @RabbitListener(bindings = @QueueBinding(
            value = @Queue(value = "${config_queue}",
                    autoDelete = "true"),
                    exchange = @Exchange(value = AppConstants.TOPIC_CONFIGURATION,
                    type= ExchangeTypes.FANOUT)
    ))
    public void configChanged(String message){
        ... application logic
    }
}

All this works great when I run the microservice. A queue with prefix config and process id gets created and is auto deleted when I stop the service.

However, when I run this service and others in their individual docker containers, all services have the same PID and that is 1.

Does anybody have any idea how I can create specify a queue that is unique to that instance.

Thanks in advance for your help.

Answer 1

Use an AnonymousQueue instead:

@SpringBootApplication
public class So72030217Application {

    public static void main(String[] args) {
        SpringApplication.run(So72030217Application.class, args);
    }

    @RabbitListener(queues = "#{configQueue.name}")
    public void listen(String in) {
        System.out.println(in);
    }

}

@Configuration
class Config {

    @Bean
    FanoutExchange fanout() {
        return new FanoutExchange("config");
    }

    @Bean
    Queue configQueue() {
        return new AnonymousQueue(new Base64UrlNamingStrategy("config_"));
    }

    @Bean
    Binding binding() {
        return BindingBuilder.bind(configQueue()).to(fanout());
    }

}

AnonymousQueues are auto-delete and use a Base64 encoded UUID in the name.