Chapter 17. Bridging brokers

It is possible to connect a broker to another broker by creating a sender or receiver broker connection element in the <broker-connections> section of broker.xml.

For a sender, the broker creates a message consumer on a queue that sends messages to another broker.

For a receiver, the broker creates a message producer on an address that receives messages from another broker.

Both elements function as a message bridge. However, there is no additional overhead required to process messages. Senders and receivers behave just like any other consumer or producer in a broker.

Specific queues can be configured by senders or receivers. Wildcard expressions can be used to match senders and receivers to specific addresses or sets of addresses. When configuring a sender or receiver, the following properties can be set:

The broker can be configured as a peer which connects to a AMQ Interconnect instance and instructs it that the broker will act as a store-and-forward queue for a given AMQP waypoint address configured on that router. In this scenario, clients connect to a router to send and receive messages using a waypoint address, and the router routes these messages to or from the queue on the broker.

This peer configuration creates a sender and receiver pair for each destination matched in the broker connections configuration on the broker. These pairs include configurations that enable the router to collaborate with the broker. This feature avoids the requirement for the router to initiate a connection and create auto-links.

With a peer configuration, the same properties are present as when there are senders and receivers. For example, a configuration where queues with names beginning queue. act as storage for the matching router waypoint address would be:

<broker-connections>
  <amqp-connection uri="tcp://HOST:PORT" name="router">
    <peer address-match="queues.#"/>
  </amqp-connection>
</broker-connections>

<addresses>
   <address name="queues.A">
     <anycast>
       <queue name="queues.A"/>
     </anycast>
   </address>
   <address name="queues.B">
     <anycast>
       <queue name="queues.B"/>
     </anycast>
   </address>
</addresses>

There must be a matching address waypoint configuration on the router. This instructs it to treat the particular router addresses the broker attaches to as waypoints. For example, see the following prefix-based router address configuration:

address {
    prefix: queue
    waypoint: yes
}