fix(platform): support shutdown in Docker environment (#366)

* Support Unix sigterm handlers

* 'Chronicle' instead of 'node'

Co-authored-by: Jochen Görtler <grtlr@users.noreply.github.com>

* Refactor shutdown module

* Remove task::spawn and channel logic from shutdown module

* Move shutdown logic to `main.rs`

Co-authored-by: Jochen Görtler <grtlr@users.noreply.github.com>
Co-authored-by: Jochen Görtler <jochen.goertler@iota.org>

bin/inx-chronicle/src/main.rs

@@ -39,10 +39,36 @@ async fn main() {
 async fn startup(scope: &mut RuntimeScope) -> Result<(), Box<dyn Error + Send + Sync>> {
     let launcher_addr = scope.spawn_actor_unsupervised(Launcher).await;
 
-    spawn_task("ctrl-c listener", async move {
-        tokio::signal::ctrl_c().await.ok();
+    spawn_task("shutdown listener", async move {
+        shutdown_signal_listener().await;
         launcher_addr.abort().await;
     });
 
     Ok(())
 }
+
+async fn shutdown_signal_listener() {
+    #[cfg(unix)]
+    {
+        use futures::future;
+        use tokio::signal::unix::{signal, Signal, SignalKind};
+
+        // Panic: none of the possible error conditions should happen.
+        let mut signals = vec![SignalKind::interrupt(), SignalKind::terminate()]
+            .iter()
+            .map(|kind| signal(*kind).unwrap())
+            .collect::<Vec<Signal>>();
+        let signal_futs = signals.iter_mut().map(|signal| Box::pin(signal.recv()));
+        let (signal_event, _, _) = future::select_all(signal_futs).await;
+
+        if signal_event.is_none() {
+            panic!("Shutdown signal stream failed, channel may have closed.");
+        }
+    }
+    #[cfg(not(unix))]
+    {
+        if let Err(e) = tokio::signal::ctrl_c().await {
+            panic!("Failed to intercept CTRL-C: {:?}.", e);
+        }
+    }
+}