feat(transport): provide generic access to connect info (#647)

tests/integration_tests/tests/connect_info.rs

@@ -0,0 +1,50 @@
+use futures_util::FutureExt;
+use integration_tests::pb::{test_client, test_server, Input, Output};
+use std::time::Duration;
+use tokio::sync::oneshot;
+use tonic::{
+    transport::{server::TcpConnectInfo, Endpoint, Server},
+    Request, Response, Status,
+};
+
+#[tokio::test]
+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.remote_addr().is_some());
+            assert!(req.extensions().get::<TcpConnectInfo>().is_some());
+
+            Ok(Response::new(Output {}))
+        }
+    }
+
+    let svc = test_server::TestServer::new(Svc);
+
+    let (tx, rx) = oneshot::channel::<()>();
+
+    let jh = tokio::spawn(async move {
+        Server::builder()
+            .add_service(svc)
+            .serve_with_shutdown("127.0.0.1:1400".parse().unwrap(), rx.map(drop))
+            .await
+            .unwrap();
+    });
+
+    tokio::time::sleep(Duration::from_millis(100)).await;
+
+    let channel = Endpoint::from_static("http://127.0.0.1:1400")
+        .connect()
+        .await
+        .unwrap();
+
+    let mut client = test_client::TestClient::new(channel);
+
+    client.unary_call(Input {}).await.unwrap();
+
+    tx.send(()).unwrap();
+
+    jh.await.unwrap();
+}