Book Image

gRPC Go for Professionals

By : Clément Jean
Book Image

gRPC Go for Professionals

By: Clément Jean

Overview of this book

In recent years, the popularity of microservice architecture has surged, bringing forth a new set of requirements. Among these, efficient communication between the different services takes center stage, and that's where gRPC shines. This book will take you through creating gRPC servers and clients in an efficient, secure, and scalable way. However, communication is just one aspect of microservices, so this book goes beyond that to show you how to deploy your application on Kubernetes and configure other tools that are needed for making your application more resilient. With these tools at your disposal, you’ll be ready to get started with using gRPC in a microservice architecture. In gRPC Go for Professionals, you'll explore core concepts such as message transmission and the role of Protobuf in serialization and deserialization. Through a step-by-step implementation of a TODO list API, you’ll see the different features of gRPC in action. You’ll then learn different approaches for testing your services and debugging your API endpoints. Finally, you’ll get to grips with deploying the application services via Docker images and Kubernetes.
Table of Contents (13 chapters)
10
Epilogue

External logic with interceptors

While some headers might be applicable to only one endpoint, most often, we want to be able to apply the same logic across different endpoints. In the case of the auth_token header, if we have multiple routes that can only be called when the user is logged in, we do not want to repeat all the checks we did in the previous section. It bloats the code; it is not maintainable; and it might distract developers when finding the heart of the endpoint. This is why we will use an authentication interceptor. We will extract that authentication logic and it will be called before each call in the API.

Our interceptors will be called authInterceptor. The interceptor on the server side will simply do all the checks we did in the previous section, and then if everything goes well, the execution of the endpoint will be launched. Otherwise, the interceptor will return the error and the endpoint will not be called.

To define a server side interceptor, we have...