Conn pool

src/default_client.rs

@@ -1,14 +1,20 @@
 #![cfg(any(feature = "native-tls-client", feature = "rustls-client"))]
 
-use bytes::Bytes;
-use http_body_util::Empty;
+use bytes::{Buf, Bytes};
+use http_body_util::{BodyExt, Empty, combinators::BoxBody};
 use hyper::{
     Request, Response, StatusCode, Uri, Version,
     body::{Body, Incoming},
     client, header,
 };
 use hyper_util::rt::{TokioExecutor, TokioIo};
-use std::task::{Context, Poll};
+use std::{
+    collections::HashMap,
+    future::poll_fn,
+    sync::Arc,
+    task::{Context, Poll},
+};
+use tokio::sync::Mutex;
 use tokio::{net::TcpStream, task::JoinHandle};
 
 #[cfg(all(feature = "native-tls-client", feature = "rustls-client"))]
@@ -55,6 +61,96 @@ pub struct Upgraded {
     /// A socket to Server
     pub server: TokioIo<hyper::upgrade::Upgraded>,
 }
+
+type DynError = Box<dyn std::error::Error + Send + Sync>;
+type PooledBody = BoxBody<Bytes, DynError>;
+type Http1Sender = hyper::client::conn::http1::SendRequest<PooledBody>;
+type Http2Sender = hyper::client::conn::http2::SendRequest<PooledBody>;
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
+enum ConnectionProtocol {
+    Http1,
+    Http2,
+}
+
+#[derive(Clone, Debug, Eq, PartialEq, Hash)]
+struct ConnectionKey {
+    host: String,
+    port: u16,
+    is_tls: bool,
+    protocol: ConnectionProtocol,
+}
+
+impl ConnectionKey {
+    fn new(host: String, port: u16, is_tls: bool, protocol: ConnectionProtocol) -> Self {
+        Self {
+            host,
+            port,
+            is_tls,
+            protocol,
+        }
+    }
+
+    fn from_uri(uri: &Uri, protocol: ConnectionProtocol) -> Result<Self, Error> {
+        let (host, port, is_tls) = host_port(uri)?;
+        Ok(ConnectionKey::new(host, port, is_tls, protocol))
+    }
+}
+
+#[derive(Clone, Default)]
+struct ConnectionPool {
+    http1: Arc<Mutex<HashMap<ConnectionKey, Vec<Http1Sender>>>>,
+    http2: Arc<Mutex<HashMap<ConnectionKey, Http2Sender>>>,
+}
+
+impl ConnectionPool {
+    async fn take_http1(&self, key: &ConnectionKey) -> Option<Http1Sender> {
+        let mut guard = self.http1.lock().await;
+        let entry = guard.get_mut(key)?;
+        while let Some(mut conn) = entry.pop() {
+            if sender_alive_http1(&mut conn).await {
+                return Some(conn);
+            }
+        }
+        if entry.is_empty() {
+            guard.remove(key);
+        }
+        None
+    }
+
+    async fn put_http1(&self, key: ConnectionKey, sender: Http1Sender) {
+        let mut guard = self.http1.lock().await;
+        guard.entry(key).or_default().push(sender);
+    }
+
+    async fn get_http2(&self, key: &ConnectionKey) -> Option<Http2Sender> {
+        let mut guard = self.http2.lock().await;
+        let mut sender = guard.get(key).cloned()?;
+
+        let alive = sender_alive_http2(&mut sender).await;
+
+        if alive {
+            Some(sender)
+        } else {
+            guard.remove(key);
+            None
+        }
+    }
+
+    async fn insert_http2_if_absent(&self, key: ConnectionKey, sender: Http2Sender) {
+        let mut guard = self.http2.lock().await;
+        guard.entry(key).or_insert(sender);
+    }
+}
+
+async fn sender_alive_http1(sender: &mut Http1Sender) -> bool {
+    poll_fn(|cx| sender.poll_ready(cx)).await.is_ok()
+}
+
+async fn sender_alive_http2(sender: &mut Http2Sender) -> bool {
+    poll_fn(|cx| sender.poll_ready(cx)).await.is_ok()
+}
+
 #[derive(Clone)]
 /// Default HTTP client for this crate
 pub struct DefaultClient {
@@ -71,6 +167,8 @@ pub struct DefaultClient {
     /// If true, send_request will returns an Upgraded struct when the response is an upgrade
     /// If false, send_request never returns an Upgraded struct and just copy bidirectional when the response is an upgrade
     pub with_upgrades: bool,
+
+    pool: ConnectionPool,
 }
 impl Default for DefaultClient {
     fn default() -> Self {
@@ -102,6 +200,7 @@ impl DefaultClient {
             tls_connector_no_alpn: tokio_native_tls::TlsConnector::from(tls_connector_no_alpn),
             tls_connector_alpn_h2: tokio_native_tls::TlsConnector::from(tls_connector_alpn_h2),
             with_upgrades: false,
+            pool: ConnectionPool::default(),
         })
     }
 
@@ -135,6 +234,7 @@ impl DefaultClient {
                 tls_connector_alpn_h2,
             )),
             with_upgrades: false,
+            pool: ConnectionPool::default(),
         })
     }
 
@@ -175,17 +275,54 @@ impl DefaultClient {
         Error,
     >
     where
-        B: Body + Unpin + Send + 'static,
-        B::Data: Send,
-        B::Error: Into<Box<dyn std::error::Error + Send + Sync>>,
+        B: Body<Data = Bytes> + Send + Sync + 'static,
+        B::Data: Send + Buf,
+        B::Error: Into<DynError>,
     {
-        let mut send_request = self.connect(req.uri(), req.version()).await?;
+        let target_uri = req.uri().clone();
+        let mut send_request = if req.version() == Version::HTTP_2 {
+            match ConnectionKey::from_uri(&target_uri, ConnectionProtocol::Http2) {
+                Ok(pool_key) => {
+                    if let Some(conn) = self.pool.get_http2(&pool_key).await {
+                        SendRequest::Http2(conn)
+                    } else {
+                        self.connect(req.uri(), req.version(), Some(pool_key))
+                            .await?
+                    }
+                }
+                Err(err) => {
+                    tracing::warn!(
+                        "ConnectionKey::from_uri failed for HTTP/2 ({}): continuing without pool",
+                        err
+                    );
+                    self.connect(req.uri(), req.version(), None).await?
+                }
+            }
+        } else {
+            match ConnectionKey::from_uri(&target_uri, ConnectionProtocol::Http1) {
+                Ok(pool_key) => {
+                    if let Some(conn) = self.pool.take_http1(&pool_key).await {
+                        SendRequest::Http1(conn)
+                    } else {
+                        self.connect(req.uri(), req.version(), Some(pool_key))
+                            .await?
+                    }
+                }
+                Err(err) => {
+                    tracing::warn!(
+                        "ConnectionKey::from_uri failed for HTTP/1 ({}): continuing without pool",
+                        err
+                    );
+                    self.connect(req.uri(), req.version(), None).await?
+                }
+            }
+        };
 
         let (req_parts, req_body) = req.into_parts();
 
-        let res = send_request
-            .send_request(Request::from_parts(req_parts.clone(), req_body))
-            .await?;
+        let boxed_req = Request::from_parts(req_parts.clone(), to_boxed_body(req_body));
+
+        let res = send_request.send_request(boxed_req).await?;
 
         if res.status() == StatusCode::SWITCHING_PROTOCOLS {
             let (res_parts, res_body) = res.into_parts();
@@ -221,36 +358,41 @@ impl DefaultClient {
 
             Ok((Response::from_parts(res_parts, res_body), upgrade))
         } else {
+            match send_request {
+                SendRequest::Http1(sender) => {
+                    if let Ok(pool_key) =
+                        ConnectionKey::from_uri(&target_uri, ConnectionProtocol::Http1)
+                    {
+                        self.pool.put_http1(pool_key, sender).await;
+                    } else {
+                        // If we couldn't build a pool key, skip pooling.
+                    }
+                }
+                SendRequest::Http2(_) => {
+                    // For HTTP/2 the pool retains a shared sender; no action needed.
+                }
+            }
             Ok((res, None))
         }
     }
 
-    async fn connect<B>(&self, uri: &Uri, http_version: Version) -> Result<SendRequest<B>, Error>
-    where
-        B: Body + Unpin + Send + 'static,
-        B::Data: Send,
-        B::Error: Into<Box<dyn std::error::Error + Send + Sync>>,
-    {
-        let host = uri
-            .host()
-            .ok_or_else(|| Error::InvalidHost(Box::new(uri.clone())))?;
-        let port =
-            uri.port_u16()
-                .unwrap_or(if uri.scheme() == Some(&hyper::http::uri::Scheme::HTTPS) {
-                    443
-                } else {
-                    80
-                });
+    async fn connect(
+        &self,
+        uri: &Uri,
+        http_version: Version,
+        key: Option<ConnectionKey>,
+    ) -> Result<SendRequest, Error> {
+        let (host, port, is_tls) = host_port(uri)?;
 
-        let tcp = TcpStream::connect((host, port)).await?;
+        let tcp = TcpStream::connect((host.as_str(), port)).await?;
         // This is actually needed to some servers
         let _ = tcp.set_nodelay(true);
 
-        if uri.scheme() == Some(&hyper::http::uri::Scheme::HTTPS) {
+        if is_tls {
             #[cfg(feature = "native-tls-client")]
             let tls = self
                 .tls_connector(http_version)
-                .connect(host, tcp)
+                .connect(&host, tcp)
                 .await
                 .map_err(|err| Error::TlsConnectError(Box::new(uri.clone()), err))?;
             #[cfg(feature = "rustls-client")]
@@ -284,6 +426,14 @@ impl DefaultClient {
 
                 tokio::spawn(conn);
 
+                if let Some(ref k) = key
+                    && matches!(k.protocol, ConnectionProtocol::Http2)
+                {
+                    self.pool
+                        .insert_http2_if_absent(k.clone(), sender.clone())
+                        .await;
+                }
+
                 Ok(SendRequest::Http2(sender))
             } else {
                 let (sender, conn) = client::conn::http1::Builder::new()
@@ -310,18 +460,15 @@ impl DefaultClient {
     }
 }
 
-enum SendRequest<B> {
-    Http1(hyper::client::conn::http1::SendRequest<B>),
-    Http2(hyper::client::conn::http2::SendRequest<B>),
+enum SendRequest {
+    Http1(Http1Sender),
+    Http2(Http2Sender),
 }
 
-impl<B> SendRequest<B>
-where
-    B: Body + 'static,
-{
+impl SendRequest {
     async fn send_request(
         &mut self,
-        mut req: Request<B>,
+        mut req: Request<PooledBody>,
     ) -> Result<Response<Incoming>, hyper::Error> {
         match self {
             SendRequest::Http1(sender) => {
@@ -357,13 +504,13 @@ where
     }
 }
 
-impl<B> SendRequest<B> {
+impl SendRequest {
     #[allow(dead_code)]
     // TODO: connection pooling
     fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), hyper::Error>> {
         match self {
             SendRequest::Http1(sender) => sender.poll_ready(cx),
-            SendRequest::Http2(sender) => sender.poll_ready(cx),
+            SendRequest::Http2(_sender) => Poll::Ready(Ok(())),
         }
     }
 }
@@ -375,3 +522,24 @@ fn remove_authority<B>(req: &mut Request<B>) -> Result<(), hyper::http::uri::Inv
     *req.uri_mut() = Uri::from_parts(parts)?;
     Ok(())
 }
+
+fn to_boxed_body<B>(body: B) -> PooledBody
+where
+    B: Body<Data = Bytes> + Send + Sync + 'static,
+    B::Data: Send + Buf,
+    B::Error: Into<DynError>,
+{
+    body.map_err(|err| err.into()).boxed()
+}
+
+fn host_port(uri: &Uri) -> Result<(String, u16, bool), Error> {
+    let host = uri
+        .host()
+        .ok_or_else(|| Error::InvalidHost(Box::new(uri.clone())))?
+        .to_string();
+    let is_tls = uri.scheme() == Some(&hyper::http::uri::Scheme::HTTPS);
+    let port = uri.port_u16().unwrap_or(if is_tls { 443 } else { 80 });
+    Ok((host, port, is_tls))
+}
+
+impl DefaultClient {}

src/lib.rs

@@ -134,7 +134,7 @@ where
         <S::ResBody as Body>::Error: Into<Box<dyn StdError + Send + Sync>>,
         S::Future: Send,
     {
-        service_fn(move |req| {
+        service_fn(move |mut req| {
             let proxy = proxy.clone();
             let mut service = service.clone();
 
@@ -151,6 +151,7 @@ where
                     };
 
                     tokio::spawn(async move {
+                        let remote_addr: Option<RemoteAddr> = req.extensions_mut().remove();
                         let client = match hyper::upgrade::on(req).await {
                             Ok(client) => client,
                             Err(err) => {
@@ -194,6 +195,9 @@ where
                                 let mut service = service.clone();
 
                                 async move {
+                                    if let Some(remote_addr) = remote_addr {
+                                        req.extensions_mut().insert(remote_addr);
+                                    }
                                     inject_authority(&mut req, connect_authority.clone());
                                     service.call(req).await
                                 }