The RabbitMQ connector fetches serialized data from the export tables and writes it to a RabbitMQ message exchange. RabbitMQ is a popular message queueing service that supports multiple platforms, multiple languages, and multiple protocols, including AMQP.

Before using the RabbitMQ connector, we strongly recommend reading the RabbitMQ documentation and becoming familiar with the software, since you will need to set up a RabbitMQ exchange, queues, and routing key filters to make use of VoltDB's RabbitMQ export functionality. The instructions in this section assume a working knowledge of RabbitMQ and the RabbitMQ operational model.

You must also install the RabbitMQ Java client library before you can use the VoltDB connector. To install the RabbitMQ Java client library:

When the RabbitMQ connector receives data from the VoltDB export tables, it establishes a connection to the RabbitMQ exchange as a producer. It then writes records to the service using the optional exchange name and routing key suffix. RabbitMQ uses the routing key to identify which queue the data is sent to. The exchange examines the routing key and based on the key value (and any filters defined for the exchange) sends each message to the appropriate queue.

Every message sent by VoltDB to RabbitMQ contains a routing key that includes the name of the export table. You can further refine the routing by appending a suffix to the table name, based on the contents of individual table columns. By default, the value of the export table's partitioning column is used as a suffix for the routing key. Alternately, you can specify a different column for each table by declaring the routing.key.suffix property as a list of table and column name pairs, separating the table from the column name with a period and separating the pairs with commas. For example:

<export enabled="true" target="rabbitmq">
   <configuration>
     <property name="broker.host">rabbitmq.mycompany.com</property>
     <property name="routing.key.suffix">
         voter_export.state,contestants_export.contestant_number
     </property>
  </configuration>
</export>

The important point to remember is that it is your responsibility to configure a RabbitMQ exchange that matches the name associated with the exchange.name property (or take the default exchange) and create queues and/or filters to match the routing keys generated by VoltDB. At a minimum, the exchange must be able to handle routing keys starting with the export tables names. This can be achieved by using a filter for each export table. For example, using the flight example in Section 13.2, “Planning your Export Strategy”, you can create filters for EXPORT_FLIGHT.*, EXPORT_CUSTOMER.*, and RESERVATION_FINAL.*.

Table 13.5, “RabbitMQ Export Properties” lists the supported properties for the RabbitMQ connector.