feat: server shutdown signal (#676)

actix-server/examples/shutdown-signal.rs

@@ -0,0 +1,51 @@
+//! Demonstrates use of the `ServerBuilder::shutdown_signal` method using `tokio-util`s
+//! `CancellationToken` helper using a nonsensical timer. In practice, this cancellation token would
+//! be wired throughout your application and typically triggered by OS signals elsewhere.
+
+use std::{io, time::Duration};
+
+use actix_rt::net::TcpStream;
+use actix_server::Server;
+use actix_service::fn_service;
+use tokio_util::sync::CancellationToken;
+use tracing::level_filters::LevelFilter;
+use tracing_subscriber::{prelude::*, EnvFilter};
+
+async fn run(stop_signal: CancellationToken) -> io::Result<()> {
+    tracing_subscriber::registry()
+        .with(tracing_subscriber::fmt::layer())
+        .with(
+            EnvFilter::builder()
+                .with_default_directive(LevelFilter::INFO.into())
+                .from_env_lossy(),
+        )
+        .init();
+
+    let addr = ("127.0.0.1", 8080);
+    tracing::info!("starting server on port: {}", &addr.0);
+
+    Server::build()
+        .bind("shutdown-signal", addr, || {
+            fn_service(|_stream: TcpStream| async { Ok::<_, io::Error>(()) })
+        })?
+        .shutdown_signal(stop_signal.cancelled_owned())
+        .workers(2)
+        .run()
+        .await
+}
+
+#[tokio::main]
+async fn main() -> io::Result<()> {
+    let stop_signal = CancellationToken::new();
+
+    tokio::spawn({
+        let stop_signal = stop_signal.clone();
+        async move {
+            tokio::time::sleep(Duration::from_secs(10)).await;
+            stop_signal.cancel();
+        }
+    });
+
+    run(stop_signal).await?;
+    Ok(())
+}