feat(tonic): rpit future for generated server traits

examples/helloworld-tutorial.md

@@ -158,7 +158,6 @@ Next up, let's implement the Greeter service we previously defined in our `.prot
 #[derive(Debug, Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,
@@ -207,7 +206,6 @@ pub mod hello_world {
 #[derive(Debug, Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/routeguide-tutorial.md

@@ -269,7 +269,6 @@ use tokio_stream::{wrappers::ReceiverStream, Stream};
 ```
 
 ```rust
-#[tonic::async_trait]
 impl RouteGuide for RouteGuideService {
     async fn get_feature(&self, _request: Request<Point>) -> Result<Response<Feature>, Status> {
         unimplemented!()
@@ -302,8 +301,8 @@ impl RouteGuide for RouteGuideService {
 }
 ```
 
-**Note**: The `tonic::async_trait` attribute macro adds support for async functions in traits. It
-uses [async-trait] internally. You can learn more about `async fn` in traits in the [async book].
+**Note**: The stubbed traits use `impl Future<...> + Send` for the return values. It
+uses RPIT internally. You can learn more about `async fn` in traits in the [async book].
 
 
 [cargo book]: https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-build-scripts

examples/src/authentication/server.rs

@@ -10,7 +10,6 @@ type EchoResult<T> = Result<Response<T>, Status>;
 #[derive(Default)]
 pub struct EchoServer {}
 
-#[tonic::async_trait]
 impl pb::echo_server::Echo for EchoServer {
     async fn unary_echo(&self, request: Request<EchoRequest>) -> EchoResult<EchoResponse> {
         let message = request.into_inner().message;

examples/src/autoreload/server.rs

@@ -10,7 +10,6 @@ pub mod hello_world {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/blocking/server.rs

@@ -12,7 +12,6 @@ pub mod hello_world {
 #[derive(Debug, Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/cancellation/server.rs

@@ -17,7 +17,6 @@ pub mod hello_world {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/codec_buffers/server.rs

@@ -20,7 +20,6 @@ use small_buf::{
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/compression/server.rs

@@ -11,7 +11,6 @@ pub mod hello_world {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/dynamic/server.rs

@@ -20,7 +20,6 @@ type EchoResult<T> = Result<Response<T>, Status>;
 #[derive(Default)]
 pub struct MyEcho {}
 
-#[tonic::async_trait]
 impl Echo for MyEcho {
     async fn unary_echo(&self, request: Request<EchoRequest>) -> EchoResult<EchoResponse> {
         println!("Got an echo request from {:?}", request.remote_addr());
@@ -43,7 +42,6 @@ fn init_echo(args: &[String], builder: &mut RoutesBuilder) {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/dynamic_load_balance/server.rs

@@ -15,7 +15,6 @@ pub struct EchoServer {
     addr: SocketAddr,
 }
 
-#[tonic::async_trait]
 impl pb::echo_server::Echo for EchoServer {
     async fn unary_echo(&self, request: Request<EchoRequest>) -> EchoResult<EchoResponse> {
         let message = format!("{} (from {})", request.into_inner().message, self.addr);

examples/src/grpc-web/server.rs

@@ -10,7 +10,6 @@ pub mod hello_world {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/h2c/server.rs

@@ -16,7 +16,6 @@ pub mod hello_world {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/health/server.rs

@@ -12,7 +12,6 @@ pub mod hello_world {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/helloworld/server.rs

@@ -10,7 +10,6 @@ pub mod hello_world {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/interceptor/server.rs

@@ -10,7 +10,6 @@ pub mod hello_world {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/json-codec/server.rs

@@ -17,7 +17,6 @@ use hello_world::greeter_server::{Greeter, GreeterServer};
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/load_balance/server.rs

@@ -15,7 +15,6 @@ pub struct EchoServer {
     addr: SocketAddr,
 }
 
-#[tonic::async_trait]
 impl pb::echo_server::Echo for EchoServer {
     async fn unary_echo(&self, request: Request<EchoRequest>) -> EchoResult<EchoResponse> {
         let message = format!("{} (from {})", request.into_inner().message, self.addr);

examples/src/mock/mock.rs

@@ -61,7 +61,6 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/multiplex/server.rs

@@ -37,7 +37,6 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,
@@ -53,7 +52,6 @@ impl Greeter for MyGreeter {
 #[derive(Default)]
 pub struct MyEcho {}
 
-#[tonic::async_trait]
 impl Echo for MyEcho {
     async fn unary_echo(
         &self,

examples/src/reflection/server.rs

@@ -11,7 +11,6 @@ mod proto {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl proto::greeter_server::Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/richer-error/server.rs

@@ -11,7 +11,6 @@ pub mod hello_world {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/richer-error/server_vec.rs

@@ -11,7 +11,6 @@ pub mod hello_world {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/routeguide/server.rs

@@ -22,7 +22,6 @@ pub struct RouteGuideService {
     features: Arc<Vec<Feature>>,
 }
 
-#[tonic::async_trait]
 impl RouteGuide for RouteGuideService {
     async fn get_feature(&self, request: Request<Point>) -> Result<Response<Feature>, Status> {
         println!("GetFeature = {:?}", request);

examples/src/streaming/server.rs

@@ -35,7 +35,6 @@ fn match_for_io_error(err_status: &Status) -> Option<&std::io::Error> {
 #[derive(Debug)]
 pub struct EchoServer {}
 
-#[tonic::async_trait]
 impl pb::echo_server::Echo for EchoServer {
     async fn unary_echo(&self, _: Request<EchoRequest>) -> EchoResult<EchoResponse> {
         Err(Status::unimplemented("not implemented"))

examples/src/tls/server.rs

@@ -16,7 +16,6 @@ type EchoResult<T> = Result<Response<T>, Status>;
 #[derive(Default)]
 pub struct EchoServer {}
 
-#[tonic::async_trait]
 impl pb::echo_server::Echo for EchoServer {
     async fn unary_echo(&self, request: Request<EchoRequest>) -> EchoResult<EchoResponse> {
         let conn_info = request

examples/src/tls_client_auth/server.rs

@@ -11,7 +11,6 @@ type EchoResult<T> = Result<Response<T>, Status>;
 #[derive(Default)]
 pub struct EchoServer {}
 
-#[tonic::async_trait]
 impl pb::echo_server::Echo for EchoServer {
     async fn unary_echo(&self, request: Request<EchoRequest>) -> EchoResult<EchoResponse> {
         let certs = request

examples/src/tls_rustls/server.rs

@@ -103,7 +103,6 @@ type EchoResult<T> = Result<Response<T>, Status>;
 #[derive(Default)]
 pub struct EchoServer {}
 
-#[tonic::async_trait]
 impl pb::echo_server::Echo for EchoServer {
     async fn unary_echo(&self, request: Request<EchoRequest>) -> EchoResult<EchoResponse> {
         let conn_info = request.extensions().get::<Arc<ConnInfo>>().unwrap();

examples/src/tower/server.rs

@@ -15,7 +15,6 @@ pub mod hello_world {
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

examples/src/tracing/server.rs

@@ -12,7 +12,6 @@ use hello_world::{
 #[derive(Debug, Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     #[tracing::instrument]
     async fn say_hello(

examples/src/uds/server.rs

@@ -21,7 +21,6 @@ use hello_world::{
 #[derive(Default)]
 pub struct MyGreeter {}
 
-#[tonic::async_trait]
 impl Greeter for MyGreeter {
     async fn say_hello(
         &self,

grpc/Cargo.toml

@@ -6,6 +6,7 @@ authors = ["gRPC Authors"]
 license = "Apache-2.0"
 
 [dependencies]
+async-trait = {version = "0.1.13"}
 url = "2.5.0"
 tokio = { version = "1.37.0", features = ["sync"] }
-tonic = { version = "0.13.0", path = "../tonic", default-features = false, features = ["codegen"] }
+tonic = { version = "0.13.0", path = "../tonic", default-features = false, features = ["codegen"] }

grpc/src/client/name_resolution/mod.rs

@@ -30,8 +30,8 @@ use std::{
     sync::Arc,
 };
 
+use async_trait::async_trait;
 use tokio::sync::Notify;
-use tonic::async_trait;
 use url::Url;
 
 use crate::attributes::Attributes;

interop/src/server.rs

@@ -22,7 +22,6 @@ type Streaming<T> = Request<tonic::Streaming<T>>;
 type Stream<T> = Pin<Box<dyn tokio_stream::Stream<Item = StdResult<T, Status>> + Send + 'static>>;
 type BoxFuture<T, E> = Pin<Box<dyn Future<Output = StdResult<T, E>> + Send + 'static>>;
 
-#[tonic::async_trait]
 impl pb::test_service_server::TestService for TestService {
     async fn empty_call(&self, _request: Request<Empty>) -> Result<Empty> {
         Ok(Response::new(Empty {}))
@@ -158,7 +157,6 @@ impl pb::test_service_server::TestService for TestService {
 #[derive(Default)]
 pub struct UnimplementedService {}
 
-#[tonic::async_trait]
 impl pb::unimplemented_service_server::UnimplementedService for UnimplementedService {
     async fn unimplemented_call(&self, _req: Request<Empty>) -> Result<Empty> {
         Err(Status::unimplemented(""))

tests/compression/src/lib.rs

@@ -44,7 +44,6 @@ impl Svc {
     }
 }
 
-#[tonic::async_trait]
 impl test_server::Test for Svc {
     async fn compress_output_unary(&self, _req: Request<()>) -> Result<Response<SomeData>, Status> {
         let data = [0_u8; UNCOMPRESSED_MIN_BODY_SIZE];

tests/default_stubs/src/lib.rs

@@ -12,7 +12,6 @@ tonic::include_proto!("test_default");
 #[derive(Debug, Default)]
 struct Svc;
 
-#[tonic::async_trait]
 impl test_server::Test for Svc {
     type ServerStreamStream = Pin<Box<dyn Stream<Item = Result<(), Status>> + Send + 'static>>;
     type BidirectionalStreamStream =
@@ -41,7 +40,6 @@ impl test_server::Test for Svc {
     }
 }
 
-#[tonic::async_trait]
 impl test_default_server::TestDefault for Svc {
     // Default unimplemented stubs provided here.
 }

tests/integration_tests/tests/client_layer.rs

@@ -13,7 +13,6 @@ use tower_http::{set_header::SetRequestHeaderLayer, trace::TraceLayer};
 async fn connect_supports_standard_tower_layers() {
     struct Svc;
 
-    #[tonic::async_trait]
     impl test_server::Test for Svc {
         async fn unary_call(&self, req: Request<Input>) -> Result<Response<Output>, Status> {
             match req.metadata().get("x-test") {

tests/integration_tests/tests/complex_tower_middleware.rs

@@ -14,7 +14,6 @@ use tower::{layer::Layer, BoxError, Service};
 async fn complex_tower_layers_work() {
     struct Svc;
 
-    #[tonic::async_trait]
     impl test_server::Test for Svc {
         async fn unary_call(&self, req: Request<Input>) -> Result<Response<Output>, Status> {
             unimplemented!()

tests/integration_tests/tests/connect_info.rs

@@ -13,7 +13,6 @@ use tonic::{
 async fn getting_connect_info() {
     struct Svc;
 
-    #[tonic::async_trait]
     impl test_server::Test for Svc {
         async fn unary_call(&self, req: Request<Input>) -> Result<Response<Output>, Status> {
             assert!(req.local_addr().is_some());
@@ -77,7 +76,6 @@ pub mod unix {
 
     struct Svc {}
 
-    #[tonic::async_trait]
     impl test_server::Test for Svc {
         async fn unary_call(&self, req: Request<Input>) -> Result<Response<Output>, Status> {
             let conn_info = req.extensions().get::<UdsConnectInfo>().unwrap();

tests/integration_tests/tests/connection.rs

@@ -9,7 +9,6 @@ use tonic::{
 
 struct Svc(Arc<Mutex<Option<oneshot::Sender<()>>>>);
 
-#[tonic::async_trait]
 impl test_server::Test for Svc {
     async fn unary_call(&self, _: Request<Input>) -> Result<Response<Output>, Status> {
         let mut l = self.0.lock().unwrap();

tests/integration_tests/tests/extensions.rs

@@ -22,7 +22,6 @@ struct ExtensionValue(i32);
 async fn setting_extension_from_interceptor() {
     struct Svc;
 
-    #[tonic::async_trait]
     impl test_server::Test for Svc {
         async fn unary_call(&self, req: Request<Input>) -> Result<Response<Output>, Status> {
             let value = req.extensions().get::<ExtensionValue>().unwrap();
@@ -72,7 +71,6 @@ async fn setting_extension_from_interceptor() {
 async fn setting_extension_from_tower() {
     struct Svc;
 
-    #[tonic::async_trait]
     impl test_server::Test for Svc {
         async fn unary_call(&self, req: Request<Input>) -> Result<Response<Output>, Status> {
             let value = req.extensions().get::<ExtensionValue>().unwrap();

tests/integration_tests/tests/http2_keep_alive.rs

@@ -8,7 +8,6 @@ use tonic::{Request, Response, Status};
 
 struct Svc;
 
-#[tonic::async_trait]
 impl test_server::Test for Svc {
     async fn unary_call(&self, _: Request<Input>) -> Result<Response<Output>, Status> {
         Ok(Response::new(Output {}))