More ergonomic support for using a unix socket with a tonic server

examples/src/uds/server.rs

@@ -1,10 +1,14 @@
 #![cfg_attr(not(unix), allow(unused_imports))]
 
-use futures::TryFutureExt;
 use std::path::Path;
 #[cfg(unix)]
 use tokio::net::UnixListener;
-use tonic::{transport::Server, Request, Response, Status};
+#[cfg(unix)]
+use tokio_stream::wrappers::UnixListenerStream;
+use tonic::{
+    transport::{server::UdsConnectInfo, Server},
+    Request, Response, Status,
+};
 
 pub mod hello_world {
     tonic::include_proto!("helloworld");
@@ -26,8 +30,13 @@ impl Greeter for MyGreeter {
     ) -> Result<Response<HelloReply>, Status> {
         #[cfg(unix)]
         {
-            let conn_info = request.extensions().get::<unix::UdsConnectInfo>().unwrap();
+            let conn_info = request.extensions().get::<UdsConnectInfo>().unwrap();
             println!("Got a request {:?} with info {:?}", request, conn_info);
+
+            // Client-side unix sockets are unnamed.
+            assert!(conn_info.peer_addr.as_ref().unwrap().is_unnamed());
+            // This should contain process credentials for the client socket.
+            assert!(conn_info.peer_cred.as_ref().is_some());
         }
 
         let reply = hello_world::HelloReply {
@@ -46,89 +55,17 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     let greeter = MyGreeter::default();
 
-    let incoming = {
-        let uds = UnixListener::bind(path)?;
-
-        async_stream::stream! {
-            loop {
-                let item = uds.accept().map_ok(|(st, _)| unix::UnixStream(st)).await;
-
-                yield item;
-            }
-        }
-    };
+    let uds = UnixListener::bind(path)?;
+    let uds_stream = UnixListenerStream::new(uds);
 
     Server::builder()
         .add_service(GreeterServer::new(greeter))
-        .serve_with_incoming(incoming)
+        .serve_with_incoming(uds_stream)
         .await?;
 
     Ok(())
 }
 
-#[cfg(unix)]
-mod unix {
-    use std::{
-        pin::Pin,
-        sync::Arc,
-        task::{Context, Poll},
-    };
-
-    use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
-    use tonic::transport::server::Connected;
-
-    #[derive(Debug)]
-    pub struct UnixStream(pub tokio::net::UnixStream);
-
-    impl Connected for UnixStream {
-        type ConnectInfo = UdsConnectInfo;
-
-        fn connect_info(&self) -> Self::ConnectInfo {
-            UdsConnectInfo {
-                peer_addr: self.0.peer_addr().ok().map(Arc::new),
-                peer_cred: self.0.peer_cred().ok(),
-            }
-        }
-    }
-
-    #[derive(Clone, Debug)]
-    pub struct UdsConnectInfo {
-        pub peer_addr: Option<Arc<tokio::net::unix::SocketAddr>>,
-        pub peer_cred: Option<tokio::net::unix::UCred>,
-    }
-
-    impl AsyncRead for UnixStream {
-        fn poll_read(
-            mut self: Pin<&mut Self>,
-            cx: &mut Context<'_>,
-            buf: &mut ReadBuf<'_>,
-        ) -> Poll<std::io::Result<()>> {
-            Pin::new(&mut self.0).poll_read(cx, buf)
-        }
-    }
-
-    impl AsyncWrite for UnixStream {
-        fn poll_write(
-            mut self: Pin<&mut Self>,
-            cx: &mut Context<'_>,
-            buf: &[u8],
-        ) -> Poll<std::io::Result<usize>> {
-            Pin::new(&mut self.0).poll_write(cx, buf)
-        }
-
-        fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<std::io::Result<()>> {
-            Pin::new(&mut self.0).poll_flush(cx)
-        }
-
-        fn poll_shutdown(
-            mut self: Pin<&mut Self>,
-            cx: &mut Context<'_>,
-        ) -> Poll<std::io::Result<()>> {
-            Pin::new(&mut self.0).poll_shutdown(cx)
-        }
-    }
-}
-
 #[cfg(not(unix))]
 fn main() {
     panic!("The `uds` example only works on unix systems!");

tests/integration_tests/Cargo.toml

@@ -12,7 +12,7 @@ version = "0.1.0"
 bytes = "1.0"
 futures-util = "0.3"
 prost = "0.9"
-tokio = {version = "1.0", features = ["macros", "rt-multi-thread", "net"]}
+tokio = {version = "1.0", features = ["fs", "macros", "rt-multi-thread", "net"]}
 tonic = {path = "../../tonic"}
 
 [dev-dependencies]

tests/integration_tests/tests/connect_info.rs

@@ -48,3 +48,76 @@ async fn getting_connect_info() {
 
     jh.await.unwrap();
 }
+
+#[cfg(unix)]
+pub mod unix {
+    use std::path::Path;
+
+    use futures_util::FutureExt;
+    use tokio::{
+        net::{UnixListener, UnixStream},
+        sync::oneshot,
+    };
+    use tokio_stream::wrappers::UnixListenerStream;
+    use tonic::{
+        transport::{server::UdsConnectInfo, Endpoint, Server, Uri},
+        Request, Response, Status,
+    };
+    use tower::service_fn;
+
+    use integration_tests::pb::{test_client, test_server, Input, Output};
+
+    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();
+
+            // Client-side unix sockets are unnamed.
+            assert!(req.remote_addr().is_none());
+            assert!(conn_info.peer_addr.as_ref().unwrap().is_unnamed());
+            // This should contain process credentials for the client socket.
+            assert!(conn_info.peer_cred.as_ref().is_some());
+
+            Ok(Response::new(Output {}))
+        }
+    }
+
+    #[tokio::test]
+    async fn getting_connect_info() {
+        let unix_socket_path = "/tmp/uds-integration-test";
+        let uds = UnixListener::bind(unix_socket_path).unwrap();
+        let uds_stream = UnixListenerStream::new(uds);
+
+        let service = test_server::TestServer::new(Svc {});
+        let (tx, rx) = oneshot::channel::<()>();
+
+        let jh = tokio::spawn(async move {
+            Server::builder()
+                .add_service(service)
+                .serve_with_incoming_shutdown(uds_stream, rx.map(drop))
+                .await
+                .unwrap();
+        });
+
+        let channel = Endpoint::try_from("http://[::]:50051")
+            .unwrap()
+            .connect_with_connector(service_fn(move |_: Uri| {
+                UnixStream::connect(unix_socket_path)
+            }))
+            .await
+            .unwrap();
+
+        let mut client = test_client::TestClient::new(channel);
+
+        client.unary_call(Input {}).await.unwrap();
+
+        tx.send(()).unwrap();
+        jh.await.unwrap();
+
+        // tokio's `UnixListener` does not cleanup the socket automatically - we need to manually
+        // remove the file at the end of the test.
+        tokio::fs::remove_file(unix_socket_path).await.unwrap();
+    }
+}

tonic/src/request.rs

@@ -202,8 +202,8 @@ impl<T> Request<T> {
     /// Get the remote address of this connection.
     ///
     /// This will return `None` if the `IO` type used
-    /// does not implement `Connected`. This currently,
-    /// only works on the server side.
+    /// does not implement `Connected` or when using a unix domain socket.
+    /// This currently only works on the server side.
     pub fn remote_addr(&self) -> Option<SocketAddr> {
         #[cfg(feature = "transport")]
         {

tonic/src/transport/server/conn.rs

@@ -4,7 +4,7 @@ use tokio::net::TcpStream;
 
 #[cfg(feature = "tls")]
 use crate::transport::Certificate;
-#[cfg(feature = "tls")]
+#[cfg(any(unix, feature = "tls"))]
 use std::sync::Arc;
 #[cfg(feature = "tls")]
 use tokio_rustls::{rustls::Session, server::TlsStream};
@@ -98,6 +98,36 @@ impl Connected for TcpStream {
     }
 }
 
+/// Connection info for Unix domain socket streams.
+///
+/// This type will be accessible through [request extensions][ext] if you're using
+/// a unix stream.
+///
+/// See [`Connected`] for more details.
+///
+/// [ext]: crate::Request::extensions
+#[cfg(unix)]
+#[cfg_attr(docsrs, doc(cfg(unix)))]
+#[derive(Clone, Debug)]
+pub struct UdsConnectInfo {
+    /// Peer address. This will be "unnamed" for client unix sockets.
+    pub peer_addr: Option<Arc<tokio::net::unix::SocketAddr>>,
+    /// Process credentials for the unix socket.
+    pub peer_cred: Option<tokio::net::unix::UCred>,
+}
+
+#[cfg(unix)]
+impl Connected for tokio::net::UnixStream {
+    type ConnectInfo = UdsConnectInfo;
+
+    fn connect_info(&self) -> Self::ConnectInfo {
+        UdsConnectInfo {
+            peer_addr: self.peer_addr().ok().map(Arc::new),
+            peer_cred: self.peer_cred().ok(),
+        }
+    }
+}
+
 impl Connected for tokio::io::DuplexStream {
     type ConnectInfo = ();
 

tonic/src/transport/server/mod.rs

@@ -17,6 +17,9 @@ pub use conn::TlsConnectInfo;
 #[cfg(feature = "tls")]
 use super::service::TlsAcceptor;
 
+#[cfg(unix)]
+pub use conn::UdsConnectInfo;
+
 use incoming::TcpIncoming;
 
 #[cfg(feature = "tls")]