connector: Add unix feature

tonic/Cargo.toml

@@ -34,6 +34,9 @@ transport = [
 ]
 tls = ["tokio-rustls"]
 tls-roots = ["rustls-native-certs"]
+unix = [
+    "hyper-unix-connector", "transport"
+]
 
 [[bench]]
 name = "bench_main"
@@ -69,6 +72,9 @@ tower-make = "=0.3.0-alpha.2a"
 tower-balance =  { version = "=0.3.0-alpha.2", optional = true }
 tower-load = { version = "=0.3.0-alpha.2", optional = true }
 
+# unix
+hyper-unix-connector = { version = "0.1.1", optional = true }
+
 # rustls
 tokio-rustls = { version = "=0.12.0-alpha.5", optional = true }
 rustls-native-certs = { version = "0.1", optional = true }

tonic/src/transport/service/connector.rs

@@ -3,21 +3,28 @@ use super::io::BoxedIo;
 use super::tls::TlsConnector;
 use http::Uri;
 use hyper::client::connect::HttpConnector;
+#[cfg(feature = "unix")]
+use hyper_unix_connector::UnixClient;
 use std::future::Future;
 use std::pin::Pin;
 use std::task::{Context, Poll};
 use tower_make::MakeConnection;
 use tower_service::Service;
 
-#[cfg(not(feature = "tls"))]
+#[cfg(all(not(feature = "unix"), not(feature = "tls")))]
 pub(crate) fn connector() -> HttpConnector {
     let mut http = HttpConnector::new();
     http.enforce_http(false);
     http.set_nodelay(true);
     http
 }
 
-#[cfg(feature = "tls")]
+#[cfg(all(feature = "unix", not(feature = "tls")))]
+pub(crate) fn connector() -> UnixClient {
+    UnixClient
+}
+
+#[cfg(all(feature = "tls", not(feature = "unix")))]
 pub(crate) fn connector(tls: Option<TlsConnector>) -> Connector {
     Connector::new(tls)
 }