gRPC: Up and Running

Chapter 4. gRPC: Under the Hood

As you have learned in previous chapters, gRPC applications communicate using RPC over the network. As a gRPC application developer, you don’t need to worry about the underlying details of how RPC is implemented, what message-encoding techniques are used, and how RPC works over the network. You use the service definition to generate either server- or client-side code for the language of your choice. All the low-level communication details are implemented in the generated code and you get some high-level abstractions to work with. However, when building complex gRPC-based systems and running them in production, it’s vital to know how gRPC works under the hood.

In this chapter, we’ll explore how the gRPC communication flow is implemented, what encoding techniques are used, how gRPC uses the underlying network communication techniques, and so on. We’ll walk you through the message flow where the client invokes a given RPC, then discuss how it gets marshaled to a gRPC call that goes over the network, how the network communication protocol is used, how it is unmarshaled at the server, how the corresponding service and remote function is invoked, and so on.

We’ll also look at how we use protocol buffers as the encoding technique and HTTP/2 as the communication protocol for gRPC. Finally, we’ll dive into the implementation architecture of gRPC and the language support stack built around it. Although the low-level details that we are going to discuss here ...