Augment every task spawned by Service with on_exit (#3581)

* Augment every task spawned by Service with `on_exit`

* Add CI test that the node exits

substrate/.gitlab-ci.yml

@@ -216,6 +216,13 @@ check-web-wasm:
     - time cargo web build -p substrate-trie
     - sccache -s
 
+node-exits:
+  stage:                           test
+  <<:                              *docker-env
+  except:
+    - /^v[0-9]+\.[0-9]+.*$/        # i.e. v1.0, v2.1rc1
+  script:
+    - ./ci/check_for_exit.sh
 
 #### stage:                        build
 

substrate/ci/check_for_exit.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+
+# Script that checks that a node exits after `SIGINT` was send.
+
+set -e
+
+cargo build --release
+./target/release/substrate --dev &
+PID=$!
+
+# Let the chain running for 60 seconds
+sleep 60
+
+# Send `SIGINT` and give the process 30 seconds to end
+kill -INT $PID
+timeout 30 tail --pid=$PID -f /dev/null

substrate/core/service/src/lib.rs

@@ -111,13 +111,15 @@ pub type TaskExecutor = Arc<dyn Executor<Box<dyn Future<Item = (), Error = ()> +
 #[derive(Clone)]
 pub struct SpawnTaskHandle {
 	sender: mpsc::UnboundedSender<Box<dyn Future<Item = (), Error = ()> + Send>>,
+	on_exit: exit_future::Exit,
 }
 
 impl Executor<Box<dyn Future<Item = (), Error = ()> + Send>> for SpawnTaskHandle {
 	fn execute(
 		&self,
-		future: Box<dyn Future<Item = (), Error = ()> + Send>
+		future: Box<dyn Future<Item = (), Error = ()> + Send>,
 	) -> Result<(), futures::future::ExecuteError<Box<dyn Future<Item = (), Error = ()> + Send>>> {
+		let future = Box::new(future.select(self.on_exit.clone()).then(|_| Ok(())));
 		if let Err(err) = self.sender.unbounded_send(future) {
 			let kind = futures::future::ExecuteErrorKind::Shutdown;
 			Err(futures::future::ExecuteError::new(kind, err.into_inner()))
@@ -350,7 +352,7 @@ macro_rules! new_impl {
 				//light_components.clone(),
 				system_rpc_tx.clone(),
 				system_info.clone(),
-				Arc::new(SpawnTaskHandle { sender: to_spawn_tx.clone() }),
+				Arc::new(SpawnTaskHandle { sender: to_spawn_tx.clone(), on_exit: exit.clone() }),
 				transaction_pool.clone(),
 				rpc_extensions.clone(),
 				keystore.clone(),
@@ -544,22 +546,25 @@ where
 	}
 
 	fn spawn_task(&self, task: impl Future<Item = (), Error = ()> + Send + 'static) {
+		let task = task.select(self.on_exit()).then(|_| Ok(()));
 		let _ = self.to_spawn_tx.unbounded_send(Box::new(task));
 	}
 
 	fn spawn_essential_task(&self, task: impl Future<Item = (), Error = ()> + Send + 'static) {
 		let essential_failed = self.essential_failed.clone();
-		let essential_task = Box::new(task.map_err(move |_| {
+		let essential_task = task.map_err(move |_| {
 			error!("Essential task failed. Shutting down service.");
 			essential_failed.store(true, Ordering::Relaxed);
-		}));
+		});
+		let task = essential_task.select(self.on_exit()).then(|_| Ok(()));
 
-		let _ = self.to_spawn_tx.unbounded_send(essential_task);
+		let _ = self.to_spawn_tx.unbounded_send(Box::new(task));
 	}
 
 	fn spawn_task_handle(&self) -> SpawnTaskHandle {
 		SpawnTaskHandle {
 			sender: self.to_spawn_tx.clone(),
+			on_exit: self.on_exit(),
 		}
 	}
 
@@ -589,7 +594,7 @@ where
 		self.transaction_pool.clone()
 	}
 
-	fn on_exit(&self) -> ::exit_future::Exit {
+	fn on_exit(&self) -> exit_future::Exit {
 		self.exit.clone()
 	}
 }

substrate/node/cli/src/service.rs

@@ -102,7 +102,6 @@ macro_rules! new_full_start {
 /// concrete types instead.
 macro_rules! new_full {
 	($config:expr) => {{
-		use futures::Future;
 		use futures::sync::mpsc;
 		use network::DhtEvent;
 
@@ -118,7 +117,7 @@ macro_rules! new_full {
 			$config.disable_grandpa
 		);
 
-		let (builder, mut import_setup, inherent_data_providers, mut tasks_to_spawn) = new_full_start!($config);
+		let (builder, mut import_setup, inherent_data_providers, tasks_to_spawn) = new_full_start!($config);
 
 		// Dht event channel from the network to the authority discovery module. Use bounded channel to ensure
 		// back-pressure. Authority discovery is triggering one event per authority within the current authority set.
@@ -138,13 +137,7 @@ macro_rules! new_full {
 				.expect("Link Half and Block Import are present for Full Services or setup failed before. qed");
 
 		// spawn any futures that were created in the previous setup steps
-		for task in tasks_to_spawn.drain(..) {
-			service.spawn_task(
-				task.select(service.on_exit())
-					.map(|_| ())
-					.map_err(|_| ())
-			);
-		}
+		tasks_to_spawn.into_iter().for_each(|t| service.spawn_task(t));
 
 		if is_authority {
 			let proposer = substrate_basic_authorship::ProposerFactory {
@@ -170,15 +163,14 @@ macro_rules! new_full {
 			};
 
 			let babe = babe::start_babe(babe_config)?;
-			let select = babe.select(service.on_exit()).then(|_| Ok(()));
-			service.spawn_task(Box::new(select));
+			service.spawn_essential_task(babe);
 
 			let authority_discovery = authority_discovery::AuthorityDiscovery::new(
 				service.client(),
 				service.network(),
 				dht_event_rx,
 			);
-			service.spawn_task(Box::new(authority_discovery));
+			service.spawn_task(authority_discovery);
 		}
 
 		let config = grandpa::Config {