Learn Rust Coding · Lesson

Implementing a gRPC Server

Serve unary RPC methods.

The Generated Server Trait

For a service named Greeter, tonic generates a trait in greeter_server. You implement it on your own struct to provide behavior.

The trait is async via #[tonic::async_trait], so each method is an async fn returning a Result.

use greeter::v1::greeter_server::{Greeter, GreeterServer};
use greeter::v1::{HelloRequest, HelloReply};

Methods take a tonic::Request<T> and return a tonic::Response<T>. These wrappers carry metadata, extensions, and the inner message.

Call .into_inner() to get the decoded message, and Response::new(..) to build a reply.

let req: HelloRequest = request.into_inner();
let reply = HelloReply { message: format!("Hi {}", req.name) };
Ok(Response::new(reply))