Chapter 4. Saga Development

In this chapter, we will be focusing on the various useful constructions of sagas and message handlers. The purpose of sagas will be discussed when the need to extend and coordinate transactional integrity by using sagas is discussed. This chapter will then morph into a discussion of NServiceBus using integrated, pre-built WCF bridges. Some might consider it unusual to discuss WCF in a saga chapter, but sagas become an intermediary for coordinating WCF and NServiceBus workflows. We can decouple the workflow from the frontend for interaction to the backend processes through message handling. Sagas provide the means to persist the state information of the messages.

We will start with unit testing saga handlers and message handlers as we are constructing them, and how NServiceBus brings rules into testing them through Visual Studio. We will briefly discuss building our own tools and then move on to changing the transport mechanics from MSMQ into RabbitMQ...