A key prerequisite for implementing any kind of distributed system is to introduce a protocol that will allow the various system components to communicate with each other. The same requirement also applies to the distributed graph processing system that we are building in this chapter.
As the workers and masters communicate with each other over network links, we will be applying the concepts learned in Chapter 9, Communicating with the Outside World, and use gRPC as our transport layer.
The message and RPC definitions from the following sections can be found in the Chapter12/dbspgraph/api folder in this book's GitHub repository.