Make TowerToHyperService crate-private

This also requires vendoring it in the rustls example, which doesn’t use a server type.

Making the type crate-private means we can delete some unused methods.

examples/Cargo.toml

@@ -280,7 +280,7 @@ tower = ["dep:hyper", "dep:hyper-util", "dep:tower", "dep:http"]
 json-codec = ["dep:serde", "dep:serde_json", "dep:bytes"]
 compression = ["tonic/gzip"]
 tls = ["tonic/tls"]
-tls-rustls = ["dep:hyper", "dep:hyper-util", "dep:hyper-rustls", "dep:tower", "tower-http/util", "tower-http/add-extension", "dep:rustls-pemfile", "dep:tokio-rustls"]
+tls-rustls = ["dep:hyper", "dep:hyper-util", "dep:hyper-rustls", "dep:tower", "tower-http/util", "tower-http/add-extension", "dep:rustls-pemfile", "dep:tokio-rustls", "dep:pin-project", "dep:http-body-util"]
 dynamic-load-balance = ["dep:tower"]
 timeout = ["tokio/time", "dep:tower"]
 tls-client-auth = ["tonic/tls"]
@@ -315,14 +315,15 @@ http = { version = "1", optional = true }
 http-body = { version = "1", optional = true }
 http-body-util = { version = "0.1", optional = true }
 hyper = { version = "1", optional = true }
-hyper-util = { version = "0.1", optional = true }
+hyper-util = { version = ">=0.1.4, <0.2", optional = true }
 listenfd = { version = "1.0", optional = true }
 bytes = { version = "1", optional = true }
 h2 = { version = "0.3", optional = true }
 tokio-rustls = { version = "0.26", optional = true, features = ["ring", "tls12"], default-features = false }
 hyper-rustls = { version = "0.27.0", features = ["http2", "ring", "tls12"], optional = true, default-features = false }
 rustls-pemfile = { version = "2.0.0", optional = true }
 tower-http = { version = "0.5", optional = true }
+pin-project = { version = "1.0.11", optional = true }
 
 [build-dependencies]
 tonic-build = { path = "../tonic-build", features = ["prost"] }

examples/src/tls_rustls/server.rs

@@ -2,6 +2,7 @@ pub mod pb {
     tonic::include_proto!("/grpc.examples.unaryecho");
 }
 
+use http_body_util::BodyExt;
 use hyper::server::conn::http2::Builder;
 use hyper_util::rt::{TokioExecutor, TokioIo};
 use pb::{EchoRequest, EchoResponse};
@@ -14,8 +15,8 @@ use tokio_rustls::{
     },
     TlsAcceptor,
 };
-use tonic::transport::server::TowerToHyperService;
-use tonic::{transport::Server, Request, Response, Status};
+use tonic::{body::BoxBody, transport::Server, Request, Response, Status};
+use tower::{BoxError, ServiceExt};
 use tower_http::ServiceBuilderExt;
 
 #[tokio::main]
@@ -122,3 +123,70 @@ impl pb::echo_server::Echo for EchoServer {
         Ok(Response::new(EchoResponse { message }))
     }
 }
+
+/// An adaptor which converts a [`tower::Service`] to a [`hyper::service::Service`].
+///
+/// The [`hyper::service::Service`] trait is used by hyper to handle incoming requests,
+/// and does not support the `poll_ready` method that is used by tower services.
+///
+/// This is provided here because the equivalent adaptor in hyper-util does not support
+/// tonic::body::BoxBody bodies.
+#[derive(Debug, Clone)]
+struct TowerToHyperService<S> {
+    service: S,
+}
+
+impl<S> TowerToHyperService<S> {
+    /// Create a new `TowerToHyperService` from a tower service.
+    fn new(service: S) -> Self {
+        Self { service }
+    }
+}
+
+impl<S> hyper::service::Service<hyper::Request<hyper::body::Incoming>> for TowerToHyperService<S>
+where
+    S: tower::Service<hyper::Request<BoxBody>> + Clone,
+    S::Error: Into<BoxError> + 'static,
+{
+    type Response = S::Response;
+    type Error = BoxError;
+    type Future = TowerToHyperServiceFuture<S, hyper::Request<BoxBody>>;
+
+    fn call(&self, req: hyper::Request<hyper::body::Incoming>) -> Self::Future {
+        let req = req.map(|incoming| {
+            incoming
+                .map_err(|err| Status::from_error(err.into()))
+                .boxed_unsync()
+        });
+        TowerToHyperServiceFuture {
+            future: self.service.clone().oneshot(req),
+        }
+    }
+}
+
+/// Future returned by [`TowerToHyperService`].
+#[derive(Debug)]
+#[pin_project::pin_project]
+struct TowerToHyperServiceFuture<S, R>
+where
+    S: tower::Service<R>,
+{
+    #[pin]
+    future: tower::util::Oneshot<S, R>,
+}
+
+impl<S, R> std::future::Future for TowerToHyperServiceFuture<S, R>
+where
+    S: tower::Service<R>,
+    S::Error: Into<BoxError> + 'static,
+{
+    type Output = Result<S::Response, BoxError>;
+
+    #[inline]
+    fn poll(
+        self: std::pin::Pin<&mut Self>,
+        cx: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Self::Output> {
+        self.project().future.poll(cx).map_err(Into::into)
+    }
+}

tonic/src/transport/server/mod.rs

@@ -10,14 +10,9 @@ mod tls;
 mod unix;
 
 use tokio_stream::StreamExt as _;
-use tower::util::BoxCloneService;
-use tower::util::Oneshot;
-use tower::ServiceExt;
-use tracing::debug;
-use tracing::trace;
+use tracing::{debug, trace};
 
-pub use super::service::Routes;
-pub use super::service::RoutesBuilder;
+pub use super::service::{Routes, RoutesBuilder};
 
 pub use conn::{Connected, TcpConnectInfo};
 use hyper_util::rt::{TokioExecutor, TokioIo};
@@ -43,19 +38,17 @@ use crate::transport::Error;
 
 use self::recover_error::RecoverError;
 use super::service::{GrpcTimeout, ServerIo};
-use crate::body::boxed;
-use crate::body::BoxBody;
+use crate::body::{boxed, BoxBody};
 use crate::server::NamedService;
 use bytes::Bytes;
 use http::{Request, Response};
 use http_body_util::BodyExt;
 use hyper::body::Incoming;
 use pin_project::pin_project;
-use std::future::poll_fn;
 use std::{
     convert::Infallible,
     fmt,
-    future::{self, Future},
+    future::{self, poll_fn, Future},
     marker::PhantomData,
     net::SocketAddr,
     pin::{pin, Pin},
@@ -69,8 +62,8 @@ use tower::{
     layer::util::{Identity, Stack},
     layer::Layer,
     limit::concurrency::ConcurrencyLimitLayer,
-    util::Either,
-    Service, ServiceBuilder,
+    util::{BoxCloneService, Either, Oneshot},
+    Service, ServiceBuilder, ServiceExt,
 };
 
 type BoxHttpBody = crate::body::BoxBody;
@@ -673,30 +666,15 @@ type ConnectionBuilder = hyper_util::server::conn::auto::Builder<TokioExecutor>;
 /// The [`hyper::service::Service`] trait is used by hyper to handle incoming requests,
 /// and does not support the `poll_ready` method that is used by tower services.
 #[derive(Debug, Copy, Clone)]
-pub struct TowerToHyperService<S> {
+pub(crate) struct TowerToHyperService<S> {
     service: S,
 }
 
 impl<S> TowerToHyperService<S> {
     /// Create a new `TowerToHyperService` from a tower service.
-    pub fn new(service: S) -> Self {
+    pub(crate) fn new(service: S) -> Self {
         Self { service }
     }
-
-    /// Extract the inner tower service.
-    pub fn into_inner(self) -> S {
-        self.service
-    }
-
-    /// Get a reference to the inner tower service.
-    pub fn as_inner(&self) -> &S {
-        &self.service
-    }
-
-    /// Get a mutable reference to the inner tower service.
-    pub fn as_inner_mut(&mut self) -> &mut S {
-        &mut self.service
-    }
 }
 
 impl<S> hyper::service::Service<Request<Incoming>> for TowerToHyperService<S>
@@ -719,7 +697,7 @@ where
 /// Future returned by [`TowerToHyperService`].
 #[derive(Debug)]
 #[pin_project]
-pub struct TowerToHyperServiceFuture<S, R>
+pub(crate) struct TowerToHyperServiceFuture<S, R>
 where
     S: tower_service::Service<R>,
 {