[rabbitmq-discuss] Naive Question

[Bell, Paul M.]

All,

Hi again.

Only after trying to think through a real world scenario did I realize that my grasp of certain fundamental AMQP concepts is tenuous.

Specifically, given a producer and a consumer, is the normative behavior for only *one* of them to declare (create?) the queue over which they communicate? As I look over the examples that I've "written" ("copied" would be more accurate), I see my producer doing this:


RabbitAdmin admin = new RabbitAdmin(rabbitTemplate.getConnectionFactory());
Exchange ex = new FanoutExchange(routingKey, true, false);
admin.declareExchange(ex);
admin.declareQueue(new Queue(this.queueName));


And I see my consumer doing this:


ConsumerSimpleMessageListenerContainer container = new ConsumerSimpleMessageListenerContainer();
container.setConnectionFactory(connectionFactory());
container.setQueueNames(this.queueName);
container.setConcurrentConsumers(this.onOfConsumer);
container.setMessageListener(new MessageListenerAdapter(new ConsumerHandler(), new SimpleMessageConverter()));
container.startConsumers();


What would happen if each declared a queue of the same name and type - would that give rise to two distinct queues, leaving the producer and consumer unable to communicate?

If it's normative for only one party to create the queue and the other to bind to it, what will happen if, when I try to bind to the queue, it doesn't yet exist?

Here's what I am trying to get to (I assume it requires a topic exchange):

a. a queue that holds two different message types, call them "MGMT" and "HB."
b. a producer writes MGMT messages to this queue
c. something called a "monitor" writes HB messages to this queue
d. consumer reads HB messages from this queue
e. monitor reads MGMT messages from this queue

Schematically I think it looks like this:

Producer(MGMT) -> monitor
Monitor(HB)    -> consumer

How would I define these relationships via RabbitMQ? Who does what to whom?! I suspect it's simple, but after two solid weeks of 10 hour days, I am fried.

Thank you for your help.

-Paul

PS: What follows is not an attempt to curry favor - but this is a really fine list; folks are friendly, knowledgeable, and eager to help. I really appreciate it.





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