feat(transport): Make service router independent from transport (#1572)

tonic/Cargo.toml

@@ -32,9 +32,10 @@ tls = ["dep:rustls-pemfile", "transport", "dep:tokio-rustls", "dep:tokio", "toki
 tls-roots = ["tls-roots-common", "dep:rustls-native-certs"]
 tls-roots-common = ["tls"]
 tls-webpki-roots = ["tls-roots-common", "dep:webpki-roots"]
+router = ["dep:axum"]
 transport = [
+  "router",
   "dep:async-stream",
-  "dep:axum",
   "channel",
   "dep:h2",
   "dep:hyper", "dep:hyper-util", "dep:hyper-timeout",

tonic/src/service/mod.rs

@@ -1,6 +1,11 @@
 //! Utilities for using Tower services with Tonic.
 
 pub mod interceptor;
+#[cfg(feature = "router")]
+pub(crate) mod router;
 
 #[doc(inline)]
 pub use self::interceptor::{interceptor, Interceptor};
+#[doc(inline)]
+#[cfg(feature = "router")]
+pub use self::router::{Routes, RoutesBuilder};

tonic/src/transport/service/router.rs → tonic/src/service/router.rs

@@ -1,7 +1,6 @@
 use crate::{
     body::{boxed, BoxBody},
     server::NamedService,
-    transport::BoxFuture,
 };
 use http::{Request, Response};
 use pin_project::pin_project;
@@ -82,10 +81,11 @@ impl Routes {
         self
     }
 
-    pub(crate) fn prepare(self) -> Self {
+    /// This makes axum perform update some internals of the router that improves perf.
+    ///
+    /// See <https://docs.rs/axum/latest/axum/routing/struct.Router.html#a-note-about-performance>
+    pub fn prepare(self) -> Self {
         Self {
-            // this makes axum perform update some internals of the router that improves perf
-            // see https://docs.rs/axum/latest/axum/routing/struct.Router.html#a-note-about-performance
             router: self.router.with_state(()),
         }
     }
@@ -142,6 +142,8 @@ struct AxumBodyService<S> {
     service: S,
 }
 
+pub(crate) type BoxFuture<'a, T> = Pin<Box<dyn Future<Output = T> + Send + 'a>>;
+
 impl<S> Service<Request<axum::body::Body>> for AxumBodyService<S>
 where
     S: Service<Request<BoxBody>, Response = Response<BoxBody>, Error = Infallible>

tonic/src/transport/mod.rs

@@ -128,4 +128,4 @@ pub use self::server::ServerTlsConfig;
 #[cfg_attr(docsrs, doc(cfg(feature = "tls")))]
 pub use self::tls::Identity;
 
-type BoxFuture<'a, T> = std::pin::Pin<Box<dyn std::future::Future<Output = T> + Send + 'a>>;
+use crate::service::router::BoxFuture;

tonic/src/transport/server/mod.rs

@@ -12,7 +12,8 @@ mod unix;
 use tokio_stream::StreamExt as _;
 use tracing::{debug, trace};
 
-pub use super::service::{Routes, RoutesBuilder};
+/// A deprecated re-export. Please use `tonic::service::{Routes, RoutesBuilder}` directly.
+pub use crate::service::{Routes, RoutesBuilder};
 
 pub use conn::{Connected, TcpConnectInfo};
 use hyper_util::rt::{TokioExecutor, TokioIo};

tonic/src/transport/service/mod.rs

@@ -6,7 +6,6 @@ pub(crate) mod executor;
 pub(crate) mod grpc_timeout;
 mod io;
 mod reconnect;
-mod router;
 #[cfg(feature = "tls")]
 mod tls;
 mod user_agent;
@@ -22,6 +21,3 @@ pub(crate) use self::io::ServerIo;
 #[cfg(feature = "tls")]
 pub(crate) use self::tls::{TlsAcceptor, TlsConnector};
 pub(crate) use self::user_agent::UserAgent;
-
-pub use self::router::Routes;
-pub use self::router::RoutesBuilder;