add self shutdown route example (#240)

Cargo.toml

@@ -27,6 +27,7 @@ members = [
    "redis-session",
    "run-in-thread",
    "rustls",
+   "self-shutdown-route",
    "server-sent-events",
    "simple-auth-server",
    "state",

self-shutdown-route/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "self-shutdown-route"
+version = "2.0.0"
+authors = ["Rob Ede <robjtede@icloud.com>"]
+edition = "2018"
+description = "Send a request to the server to shut it down"
+
+[dependencies]
+actix-web = "2.0.0"
+actix-rt = "1.0.0"
+env_logger = "0.7"
+futures = "0.3"

self-shutdown-route/README.md

@@ -0,0 +1,24 @@
+# self-shutdown-route
+
+> Demonstrates how to shutdown the web server using a route hosted by the server itself using channels.
+
+This technique can be easily modified to support shutting down the server using other kinds of external events.
+Created in response to actix/actix-web#1315. 
+
+## Usage
+
+### Running The Server
+
+```bash
+cargo run --bin self-shutdown-route
+
+# Starting 8 workers
+# Starting "actix-web-service-127.0.0.1:8080" service on 127.0.0.1:8080
+```
+
+### Available Routes
+
+- [GET /hello](http://localhost:8080/hello)
+  - Regular hello world route
+- [POST /stop](http://localhost:8080/stop)
+  - Calling this will shutdown the server and exit

self-shutdown-route/src/main.rs

@@ -0,0 +1,56 @@
+use std::{sync::mpsc, thread};
+
+use futures::executor;
+
+use actix_web::{get, middleware, post, web, App, HttpResponse, HttpServer};
+
+#[get("/hello")]
+async fn hello() -> &'static str {
+    "Hello world!"
+}
+
+#[post("/stop")]
+async fn stop(stopper: web::Data<mpsc::Sender<()>>) -> HttpResponse {
+    // make request that sends message through the Sender
+    stopper.send(()).unwrap();
+
+    HttpResponse::NoContent().finish()
+}
+
+#[actix_rt::main]
+async fn main() -> std::io::Result<()> {
+    std::env::set_var("RUST_LOG", "actix_server=debug,actix_web=debug");
+    env_logger::init();
+
+    // create a channel
+    let (tx, rx) = mpsc::channel::<()>();
+
+    let bind = "127.0.0.1:8080";
+
+    // start server as normal but don't .await after .run() yet
+    let server = HttpServer::new(move || {
+        // give the server a Sender in .data
+        let stopper = tx.clone();
+
+        App::new()
+            .data(stopper)
+            .wrap(middleware::Logger::default())
+            .service(hello)
+            .service(stop)
+    })
+    .bind(&bind)?
+    .run();
+
+    // clone the Server handle
+    let srv = server.clone();
+    thread::spawn(move || {
+        // wait for shutdown signal
+        rx.recv().unwrap();
+
+        // stop server gracefully
+        executor::block_on(srv.stop(true))
+    });
+
+    // run server
+    server.await
+}