feat: add GracefulShutdown helper (#127)

Co-authored-by: glendc <glen.decauwsemaecker@otainsight.com>

Cargo.toml

@@ -35,7 +35,7 @@ tower = { version = "0.4.1", optional = true, default-features = false, features
 hyper = { version = "1.3.0", features = ["full"] }
 bytes = "1"
 http-body-util = "0.1.0"
-tokio = { version = "1", features = ["macros", "test-util"] }
+tokio = { version = "1", features = ["macros", "test-util", "signal"] }
 tokio-test = "0.4"
 pretty_env_logger = "0.5"
 
@@ -51,6 +51,7 @@ full = [
     "client-legacy",
     "server",
     "server-auto",
+    "server-graceful",
     "service",
     "http1",
     "http2",
@@ -62,6 +63,7 @@ client-legacy = ["client", "dep:socket2", "tokio/sync"]
 
 server = ["hyper/server"]
 server-auto = ["server", "http1", "http2"]
+server-graceful = ["server", "tokio/sync"]
 
 service = ["dep:tower", "dep:tower-service"]
 
@@ -80,3 +82,7 @@ required-features = ["client-legacy", "http1", "tokio"]
 [[example]]
 name = "server"
 required-features = ["server", "http1", "tokio"]
+
+[[example]]
+name = "server_graceful"
+required-features = ["tokio", "server-graceful", "server-auto"]

examples/server_graceful.rs

@@ -0,0 +1,64 @@
+use bytes::Bytes;
+use std::convert::Infallible;
+use std::pin::pin;
+use std::time::Duration;
+use tokio::net::TcpListener;
+
+#[tokio::main(flavor = "current_thread")]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let listener = TcpListener::bind("127.0.0.1:8080").await?;
+
+    let server = hyper_util::server::conn::auto::Builder::new(hyper_util::rt::TokioExecutor::new());
+    let graceful = hyper_util::server::graceful::GracefulShutdown::new();
+    let mut ctrl_c = pin!(tokio::signal::ctrl_c());
+
+    loop {
+        tokio::select! {
+            conn = listener.accept() => {
+                let (stream, peer_addr) = match conn {
+                    Ok(conn) => conn,
+                    Err(e) => {
+                        eprintln!("accept error: {}", e);
+                        tokio::time::sleep(Duration::from_secs(1)).await;
+                        continue;
+                    }
+                };
+                eprintln!("incomming connection accepted: {}", peer_addr);
+
+                let stream = hyper_util::rt::TokioIo::new(Box::pin(stream));
+
+                let conn = server.serve_connection_with_upgrades(stream, hyper::service::service_fn(|_| async move {
+                        tokio::time::sleep(Duration::from_secs(5)).await;  // emulate slow request
+                        let body = http_body_util::Full::<Bytes>::from("Hello World!".to_owned());
+                        Ok::<_, Infallible>(http::Response::new(body))
+                    }));
+
+                let conn = graceful.watch(conn.into_owned());
+
+                tokio::spawn(async move {
+                    if let Err(err) = conn.await {
+                        eprintln!("connection error: {}", err);
+                    }
+                    eprintln!("connection dropped: {}", peer_addr);
+                });
+            },
+
+            _ = ctrl_c.as_mut() => {
+                drop(listener);
+                eprintln!("Ctrl-C received, starting shutdown");
+                    break;
+            }
+        }
+    }
+
+    tokio::select! {
+        _ = graceful.shutdown() => {
+            eprintln!("Gracefully shutdown!");
+        },
+        _ = tokio::time::sleep(Duration::from_secs(10)) => {
+            eprintln!("Waited 10 seconds for graceful shutdown, aborting...");
+        }
+    }
+
+    Ok(())
+}