server.rs

use tonic::{transport::Server, Request, Response, Status};

pub mod hello_world {
    tonic::include_proto!("helloworld");
}

use hello_world::{
    greeter_server::{Greeter, GreeterServer},
    HelloReply, HelloRequest,
};

#[derive(Debug, Default)]
pub struct MyGreeter {}

#[tonic::async_trait]
impl Greeter for MyGreeter {
    #[tracing::instrument]
    async fn say_hello(
        &self,
        request: Request<HelloRequest>,
    ) -> Result<Response<HelloReply>, Status> {
        tracing::info!("received request");

        let reply = hello_world::HelloReply {
            message: format!("Hello {}!", request.into_inner().name),
        };

        tracing::debug!("sending response");

        Ok(Response::new(reply))
    }
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    tracing_subscriber::fmt()
        .with_max_level(tracing::Level::DEBUG)
        .init();

    let addr = "[::1]:50051".parse().unwrap();
    let greeter = MyGreeter::default();

    tracing::info!(message = "Starting server.", %addr);

    Server::builder()
        .trace_fn(|_| tracing::info_span!("helloworld_server"))
        .add_service(GreeterServer::new(greeter))
        .serve(addr)
        .await?;

    Ok(())
}