Before delving into the code, let's quickly summarize what Clever Coney Media (CCM) wants to achieve with RabbitMQ. As said in the previous chapter, it wants to add an application inbox to allow users of its web application to send messages to each other. The expected user experience is more like that of an e-mail than instant messaging, though messages will be transient by definition; once received, it will not be possible to read it again. Thus, message queuing is a perfect match for it; each user will have a dedicated message queue where messages will wait until retrieval.

The following diagram illustrates the architecture CCM has in place and where RabbitMQ will fit in:

CCM's main application architecture

From what you've learned in Chapter 1, A Rabbit Springs to Life, you need to establish a physical (network) connection between the application servers and RabbitMQ, which will multiplex many logical channels. Unlike creating channels, creating connections is a costly...