grpc-spring

gRPC Spring Boot Starter is a library that makes it easier to use gRPC inside Java applications built with Spring Boot. gRPC is a communication protocol created by Google that lets different services or programs talk to each other quickly and efficiently, often across a network. Spring Boot is a popular Java framework that helps developers build server-side applications with minimal setup. Normally, wiring gRPC into a Spring Boot app requires a fair amount of manual configuration. This library handles most of that automatically.

On the server side, you annotate your service implementation class with @GrpcService and the library automatically starts and configures a gRPC server for you. By default it listens on port 9090, and you can change this and other settings through standard Spring configuration properties. On the client side, you annotate a field in your code with @GrpcClient and give it the name of the server you want to call. The library automatically creates and manages the network connection and the client stub, which is the object you use to make calls to the remote service.

The library also integrates with several other Spring ecosystem tools. It works with Spring Security for authentication and authorization, Spring Cloud for service discovery (so clients can find servers automatically in platforms like Consul or Eureka), and Spring Sleuth for distributed tracing so you can follow a request as it flows through multiple services. Metrics are collected automatically through Micrometer, which plugs into Spring Boot Actuator for monitoring. You can also register custom interceptors that run before or after calls on either the client or server side.

It can be added to a project using either Maven or Gradle with a single dependency entry. The library works with multiple variants of the gRPC Java ecosystem, including Kotlin and reactive programming extensions. It can also be used without Spring Boot, though that requires more manual configuration.