gRPC 서버 구현하기

생성된 서버 특성

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

요청 및 응답 래퍼

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

서버 구조체

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

단일 요청 메서드 구현하기

#[tonic::async_trait]
impl Greeter for MyGreeter {
    async fn say_hello(&self, request: Request<HelloRequest>)
        -> Result<Response<HelloReply>, Status> {
        let name = request.into_inner().name;
        Ok(Response::new(HelloReply { message: format!("Hello {name}") }))
    }
}

Status로 오류 반환하기

if name.is_empty() {
    return Err(Status::invalid_argument("name must not be empty"));
}

빌드하고 서비스 제공하기

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let addr = "[::1]:50051".parse()?;
    Server::builder()
        .add_service(GreeterServer::new(MyGreeter::default()))
        .serve(addr)
        .await?;
    Ok(())
}

서버 스트리밍 응답

use tokio_stream::wrappers::ReceiverStream;
let (tx, rx) = tokio::sync::mpsc::channel(8);
tokio::spawn(async move { tx.send(Ok(reply)).await.ok(); });
Ok(Response::new(ReceiverStream::new(rx)))

메타데이터 읽기

if let Some(token) = request.metadata().get("authorization") {
    // validate token
} else {
    return Err(Status::unauthenticated("missing token"));
}

인터셉터

fn auth(req: Request<()>) -> Result<Request<()>, Status> {
    match req.metadata().get("authorization") {
        Some(_) => Ok(req),
        None => Err(Status::unauthenticated("no token")),
    }
}
// .add_service(GreeterServer::with_interceptor(svc, auth))

정상적인 종료

Server::builder()
    .add_service(GreeterServer::new(MyGreeter::default()))
    .serve_with_shutdown(addr, async {
        tokio::signal::ctrl_c().await.ok();
    })
    .await?;

공유 상태

use std::sync::Arc;
use tokio::sync::Mutex;

#[derive(Default)]
pub struct MyGreeter {
    hits: Arc<Mutex<u64>>,
}

빠른 확인

복습