feat(anvil): shutdown on sigterm (#4676)

* feat(anvil): shutdown on sigterm

* rustfmt

* support on windows

Author: mattsse

anvil/src/cmd.rs

@@ -287,9 +287,30 @@ impl NodeArgs {
         let mut state_dumper = PeriodicStateDumper::new(api, dump_state, dump_interval);
 
         task_manager.spawn(async move {
+            // wait for the SIGTERM signal on unix systems
+            #[cfg(unix)]
+            let mut sigterm = Box::pin(async {
+                if let Ok(mut stream) =
+                    tokio::signal::unix::signal(tokio::signal::unix::SignalKind::terminate())
+                {
+                    stream.recv().await;
+                } else {
+                    futures::future::pending::<()>().await;
+                }
+            });
+
+            // on windows, this will never fires
+            #[cfg(not(unix))]
+            let mut sigterm = Box::pin(futures::future::pending::<()>());
+
             // await shutdown signal but also periodically flush state
             tokio::select! {
-                _ = &mut on_shutdown =>{}
+                 _ = &mut sigterm => {
+                    trace!("received sigterm signal, shutting down");
+                },
+                _ = &mut on_shutdown =>{
+
+                }
                 _ = &mut state_dumper =>{}
             }