RabbitMQ RPC across multiple rabbitMQ instances

Question

I have three clients each with their own RabbitMQ instances and I have an application (let\'s call it appA) that has its own RabbitMQ instance, the three client applications

Answer 1

It's been awhile, but if you're using Spring you can create as many connection factories as you want, with their own configurations (host, user/pass, vhost, etc.), just like you did:

@Bean
@Primary
public ConnectionFactory amqpConnectionFactory1() {
    final CachingConnectionFactory connectionFactory = new CachingConnectionFactory();

    connectionFactory.setAddresses("...");
    connectionFactory.setUsername("...");
    connectionFactory.setPassword("...");
    connectionFactory.setVirtualHost("...");

    return connectionFactory;
}

@Bean
public ConnectionFactory amqpConnectionFactory2() {
    final CachingConnectionFactory connectionFactory = new CachingConnectionFactory();

    // ...

    return connectionFactory;
}

And your rabbit admin/template's as you go:

@Bean
@Primary
public RabbitAdmin rabbitAdmin1() {
    return new RabbitAdmin(amqpConnectionFactory1());
}

@Bean
public RabbitAdmin rabbitAdmin2() {
    return new RabbitAdmin(amqpConnectionFactory2());
}

// ...

@Bean
@Primary
public RabbitTemplate rabbitTemplate1() {
    RabbitTemplate rabbitTemplate = new RabbitTemplate(amqpConnectionFactory1());

    // ...

    return rabbitTemplate;
}

@Bean
public RabbitTemplate rabbitTemplate2() {
    RabbitTemplate rabbitTemplate = new RabbitTemplate(amqpConnectionFactory2());

    // ...

    return rabbitTemplate;
}

Note that you have to provide the @Primary tag to enable one main bean, once Spring doesn't know which one to choose when you don't inform the name explicitly.

With this in hands, just inject them normally along your components:

@Autowired
private RabbitTemplate template;

// ...

@Autowired
@Qualifier("rabbitTemplate2") // Needed when want to use the non-primary bean
private RabbitTemplate template;

Hope it helps! :)

Answer 2

Take a look at org.springframework.amqp.rabbit.connection.AbstractRoutingConnectionFactory. It will allow you to create multiple connection factories to different vhosts or different rabbitmq instances. We are using it for a multi tenant rabbitmq application.