Use SpawnNamed instead of Spawn in Overseer (#1430)

* Use SpawnNamed instead of Spawn in Overseer

* reexport SpawnNamed and fix doc tests

* Fix deps

polkadot/Cargo.lock

@@ -4457,6 +4457,7 @@ dependencies = [
  "polkadot-primitives",
  "polkadot-subsystem-test-helpers",
  "sc-network",
+ "sp-core",
  "sp-runtime",
  "streamunordered",
 ]
@@ -4538,6 +4539,7 @@ dependencies = [
  "parity-scale-codec",
  "polkadot-primitives",
  "polkadot-statement-table",
+ "sp-core",
  "sp-runtime",
 ]
 
@@ -4571,9 +4573,11 @@ dependencies = [
  "futures-timer 3.0.2",
  "kv-log-macro",
  "log 0.4.8",
+ "polkadot-node-primitives",
  "polkadot-node-subsystem",
  "polkadot-primitives",
  "sc-client-api",
+ "sp-core",
  "streamunordered",
 ]
 
@@ -4611,6 +4615,7 @@ dependencies = [
  "polkadot-primitives",
  "polkadot-subsystem-test-helpers",
  "sc-network",
+ "sp-core",
  "sp-runtime",
  "streamunordered",
 ]
@@ -4963,6 +4968,7 @@ dependencies = [
  "polkadot-node-subsystem",
  "polkadot-primitives",
  "polkadot-subsystem-test-helpers",
+ "sp-core",
  "sp-keyring",
  "sp-runtime",
  "sp-staking",
@@ -4986,6 +4992,7 @@ dependencies = [
  "futures 0.3.5",
  "parking_lot 0.10.2",
  "polkadot-node-subsystem",
+ "sp-core",
 ]
 
 [[package]]

polkadot/node/core/backing/Cargo.toml

@@ -10,7 +10,6 @@ sp-api = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sc-client-api = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-blockchain = { git = "https://github.com/paritytech/substrate", branch = "master" }
 keystore = { package = "sc-keystore", git = "https://github.com/paritytech/substrate", branch = "master" }
-primitives = { package = "sp-core", git = "https://github.com/paritytech/substrate", branch = "master" }
 polkadot-primitives = { path = "../../../primitives" }
 polkadot-node-primitives = { path = "../../primitives" }
 polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem" }
@@ -20,6 +19,7 @@ derive_more = "0.99.9"
 bitvec = { version = "0.17.4", default-features = false, features = ["alloc"] }
 
 [dev-dependencies]
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master" }
 futures = { version = "0.3.5", features = ["thread-pool"] }
 subsystem-test = { package = "polkadot-subsystem-test-helpers", path = "../../test-helpers/subsystem" }

polkadot/node/core/backing/src/lib.rs

@@ -24,7 +24,6 @@ use std::sync::Arc;
 use bitvec::vec::BitVec;
 use futures::{
 	channel::{mpsc, oneshot},
-	task::{Spawn, SpawnError},
 	Future, FutureExt, SinkExt, StreamExt,
 };
 
@@ -37,7 +36,7 @@ use polkadot_primitives::v1::{
 };
 use polkadot_node_primitives::{
 	FromTableMisbehavior, Statement, SignedFullStatement, MisbehaviorReport,
-	ValidationOutputs, ValidationResult,
+	ValidationOutputs, ValidationResult, SpawnNamed,
 };
 use polkadot_subsystem::{
 	Subsystem, SubsystemContext, SpawnedSubsystem,
@@ -77,8 +76,6 @@ enum Error {
 	#[from]
 	Mpsc(mpsc::SendError),
 	#[from]
-	Spawn(SpawnError),
-	#[from]
 	UtilError(util::Error),
 }
 
@@ -735,7 +732,7 @@ pub struct CandidateBackingSubsystem<Spawner, Context> {
 
 impl<Spawner, Context> CandidateBackingSubsystem<Spawner, Context>
 where
-	Spawner: Clone + Spawn + Send + Unpin,
+	Spawner: Clone + SpawnNamed + Send + Unpin,
 	Context: SubsystemContext,
 	ToJob: From<<Context as SubsystemContext>::Message>,
 {
@@ -754,7 +751,7 @@ where
 
 impl<Spawner, Context> Subsystem<Context> for CandidateBackingSubsystem<Spawner, Context>
 where
-	Spawner: Spawn + Send + Clone + Unpin + 'static,
+	Spawner: SpawnNamed + Send + Clone + Unpin + 'static,
 	Context: SubsystemContext,
 	<Context as SubsystemContext>::Message: Into<ToJob>,
 {
@@ -769,10 +766,7 @@ where
 mod tests {
 	use super::*;
 	use assert_matches::assert_matches;
-	use futures::{
-		executor::{self, ThreadPool},
-		future, Future,
-	};
+	use futures::{executor, future, Future};
 	use polkadot_primitives::v1::{
 		AssignmentKind, BlockData, CandidateCommitments, CollatorId, CoreAssignment, CoreIndex,
 		LocalValidationData, GlobalValidationSchedule, GroupIndex, HeadData,
@@ -905,7 +899,7 @@ mod tests {
 	}
 
 	fn test_harness<T: Future<Output=()>>(keystore: KeyStorePtr, test: impl FnOnce(TestHarness) -> T) {
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 
 		let (context, virtual_overseer) = subsystem_test::make_subsystem_context(pool.clone());
 

polkadot/node/network/bridge/Cargo.toml

@@ -20,3 +20,4 @@ polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsys
 parking_lot = "0.10.0"
 subsystem-test = { package = "polkadot-subsystem-test-helpers", path = "../../test-helpers/subsystem" }
 assert_matches = "1.3.0"
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }

polkadot/node/network/bridge/src/lib.rs

@@ -184,7 +184,10 @@ impl<Net, Context> Subsystem<Context> for NetworkBridge<Net>
 	fn start(self, ctx: Context) -> SpawnedSubsystem {
 		// Swallow error because failure is fatal to the node and we log with more precision
 		// within `run_network`.
-		SpawnedSubsystem(run_network(self.0, ctx).map(|_| ()).boxed())
+		SpawnedSubsystem {
+			name: "network-bridge-subsystem",
+			future: run_network(self.0, ctx).map(|_| ()).boxed(),
+		}
 	}
 }
 
@@ -521,7 +524,7 @@ async fn run_network<N: Network>(
 mod tests {
 	use super::*;
 	use futures::channel::mpsc;
-	use futures::executor::{self, ThreadPool};
+	use futures::executor;
 
 	use std::sync::Arc;
 	use parking_lot::Mutex;
@@ -632,8 +635,7 @@ mod tests {
 	}
 
 	fn test_harness<T: Future<Output=()>>(test: impl FnOnce(TestHarness) -> T) {
-		let pool = ThreadPool::new().unwrap();
-
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (network, network_handle) = new_test_network();
 		let (context, virtual_overseer) = subsystem_test::make_subsystem_context(pool);
 

polkadot/node/network/pov-distribution/Cargo.toml

@@ -20,3 +20,4 @@ polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsys
 parking_lot = "0.10.0"
 subsystem-test = { package = "polkadot-subsystem-test-helpers", path = "../../test-helpers/subsystem" }
 assert_matches = "1.3.0"
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }

polkadot/node/network/pov-distribution/src/lib.rs

@@ -69,7 +69,10 @@ impl<C> Subsystem<C> for PoVDistribution
 	fn start(self, ctx: C) -> SpawnedSubsystem {
 		// Swallow error because failure is fatal to the node and we log with more precision
 		// within `run`.
-		SpawnedSubsystem(run(ctx).map(|_| ()).boxed())
+		SpawnedSubsystem {
+			name: "pov-distribution-subsystem",
+			future: run(ctx).map(|_| ()).boxed(),
+		}
 	}
 }
 
@@ -548,7 +551,7 @@ async fn run(
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use futures::executor::{self, ThreadPool};
+	use futures::executor;
 	use polkadot_primitives::v1::BlockData;
 	use assert_matches::assert_matches;
 
@@ -616,7 +619,7 @@ mod tests {
 			our_view: View(vec![hash_a, hash_b]),
 		};
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 		let mut descriptor = CandidateDescriptor::default();
 		descriptor.pov_hash = pov_hash;
@@ -696,7 +699,7 @@ mod tests {
 			our_view: View(vec![hash_a]),
 		};
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 		let mut descriptor = CandidateDescriptor::default();
 		descriptor.pov_hash = pov_hash;
@@ -774,7 +777,7 @@ mod tests {
 			our_view: View(vec![hash_a]),
 		};
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 
 		executor::block_on(async move {
@@ -846,7 +849,7 @@ mod tests {
 			our_view: View(vec![hash_a]),
 		};
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 
 		executor::block_on(async move {
@@ -934,7 +937,7 @@ mod tests {
 			our_view: View(vec![hash_a]),
 		};
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 
 		executor::block_on(async move {
@@ -997,7 +1000,7 @@ mod tests {
 			our_view: View(vec![hash_a]),
 		};
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 
 		executor::block_on(async move {
@@ -1058,7 +1061,7 @@ mod tests {
 			our_view: View(vec![hash_a]),
 		};
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 
 		executor::block_on(async move {
@@ -1116,7 +1119,7 @@ mod tests {
 			our_view: View(vec![hash_a]),
 		};
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 
 		executor::block_on(async move {
@@ -1201,7 +1204,7 @@ mod tests {
 			our_view: View(vec![hash_a, hash_b]),
 		};
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 
 		executor::block_on(async move {
@@ -1263,7 +1266,7 @@ mod tests {
 			our_view: View(vec![hash_a]),
 		};
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 
 		executor::block_on(async move {
@@ -1340,7 +1343,7 @@ mod tests {
 			our_view: View(vec![hash_a]),
 		};
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 
 		executor::block_on(async move {
@@ -1424,7 +1427,7 @@ mod tests {
 			our_view: View(vec![hash_a]),
 		};
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 
 		executor::block_on(async move {

polkadot/node/network/statement-distribution/Cargo.toml

@@ -24,3 +24,4 @@ parking_lot = "0.10.0"
 subsystem-test = { package = "polkadot-subsystem-test-helpers", path = "../../test-helpers/subsystem" }
 assert_matches = "1.3.0"
 sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }

polkadot/node/network/statement-distribution/src/lib.rs

@@ -70,7 +70,10 @@ impl<C> Subsystem<C> for StatementDistribution
 	fn start(self, ctx: C) -> SpawnedSubsystem {
 		// Swallow error because failure is fatal to the node and we log with more precision
 		// within `run`.
-		SpawnedSubsystem(run(ctx).map(|_| ()).boxed())
+		SpawnedSubsystem {
+			name: "statement-distribution-subsystem",
+			future: run(ctx).map(|_| ()).boxed(),
+		}
 	}
 }
 
@@ -892,7 +895,7 @@ mod tests {
 	use node_primitives::Statement;
 	use polkadot_primitives::v1::CommittedCandidateReceipt;
 	use assert_matches::assert_matches;
-	use futures::executor::{self, ThreadPool};
+	use futures::executor;
 
 	#[test]
 	fn active_head_accepts_only_2_seconded_per_validator() {
@@ -1209,7 +1212,7 @@ mod tests {
 			},
 		};
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 		let peer = PeerId::random();
 
@@ -1301,7 +1304,7 @@ mod tests {
 			(peer_c.clone(), peer_data_from_view(peer_c_view)),
 		].into_iter().collect();
 
-		let pool = ThreadPool::new().unwrap();
+		let pool = sp_core::testing::SpawnBlockingExecutor::new();
 		let (mut ctx, mut handle) = subsystem_test::make_subsystem_context(pool);
 
 		executor::block_on(async move {

polkadot/node/overseer/Cargo.toml

@@ -12,9 +12,11 @@ streamunordered = "0.5.1"
 polkadot-primitives = { path = "../../primitives" }
 client = { package = "sc-client-api", git = "https://github.com/paritytech/substrate", branch = "master" }
 polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../subsystem" }
+polkadot-node-primitives = { package = "polkadot-node-primitives", path = "../primitives" }
 async-trait = "0.1"
 
 [dev-dependencies]
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 futures = { version = "0.3.5", features = ["thread-pool"] }
 futures-timer = "3.0.2"
 femme = "2.0.1"

polkadot/node/overseer/examples/minimal-example.rs

@@ -21,7 +21,7 @@
 use std::time::Duration;
 use futures::{
 	channel::oneshot,
-	pending, pin_mut, executor, select, stream,
+	pending, pin_mut, select, stream,
 	FutureExt, StreamExt,
 };
 use futures_timer::Delay;
@@ -77,9 +77,14 @@ impl<C> Subsystem<C> for Subsystem1
 	where C: SubsystemContext<Message=CandidateBackingMessage>
 {
 	fn start(self, ctx: C) -> SpawnedSubsystem {
-		SpawnedSubsystem(Box::pin(async move {
+		let future = Box::pin(async move {
 			Self::run(ctx).await;
-		}))
+		});
+
+		SpawnedSubsystem {
+			name: "subsystem-1",
+			future,
+		}
 	}
 }
 
@@ -87,12 +92,15 @@ struct Subsystem2;
 
 impl Subsystem2 {
 	async fn run(mut ctx: impl SubsystemContext<Message=CandidateValidationMessage>)  {
-		ctx.spawn(Box::pin(async {
-			loop {
-				log::info!("Job tick");
-				Delay::new(Duration::from_secs(1)).await;
-			}
-		})).await.unwrap();
+		ctx.spawn(
+			"subsystem-2-job",
+			Box::pin(async {
+				loop {
+					log::info!("Job tick");
+					Delay::new(Duration::from_secs(1)).await;
+				}
+			}),
+		).await.unwrap();
 
 		loop {
 			match ctx.try_recv().await {
@@ -114,16 +122,20 @@ impl<C> Subsystem<C> for Subsystem2
 	where C: SubsystemContext<Message=CandidateValidationMessage>
 {
 	fn start(self, ctx: C) -> SpawnedSubsystem {
-		SpawnedSubsystem(Box::pin(async move {
+		let future = Box::pin(async move {
 			Self::run(ctx).await;
-		}))
+		});
+
+		SpawnedSubsystem {
+			name: "subsystem-2",
+			future,
+		}
 	}
 }
 
 fn main() {
 	femme::with_level(femme::LevelFilter::Trace);
-	let spawner = executor::ThreadPool::new().unwrap();
-
+	let spawner = sp_core::testing::SpawnBlockingExecutor::new();
 	futures::executor::block_on(async {
 		let timer_stream = stream::repeat(()).then(|_| async {
 			Delay::new(Duration::from_secs(1)).await;

polkadot/node/overseer/src/lib.rs

@@ -64,9 +64,8 @@ use std::collections::HashSet;
 use futures::channel::{mpsc, oneshot};
 use futures::{
 	pending, poll, select,
-	future::{BoxFuture, RemoteHandle},
+	future::BoxFuture,
 	stream::{self, FuturesUnordered},
-	task::{Spawn, SpawnExt},
 	Future, FutureExt, SinkExt, StreamExt,
 };
 use futures_timer::Delay;
@@ -86,6 +85,7 @@ pub use polkadot_subsystem::{
 	Subsystem, SubsystemContext, OverseerSignal, FromOverseer, SubsystemError, SubsystemResult,
 	SpawnedSubsystem,
 };
+use polkadot_node_primitives::SpawnNamed;
 
 
 // A capacity of bounded channels inside the overseer.
@@ -109,8 +109,8 @@ enum ToOverseer {
 	/// spawn on the overseer and a `oneshot::Sender` to signal the result
 	/// of the spawn.
 	SpawnJob {
+		name: &'static str,
 		s: BoxFuture<'static, ()>,
-		res: oneshot::Sender<SubsystemResult<()>>,
 	},
 }
 
@@ -279,14 +279,15 @@ impl<M: Send + 'static> SubsystemContext for OverseerSubsystemContext<M> {
 		self.rx.next().await.ok_or(SubsystemError)
 	}
 
-	async fn spawn(&mut self, s: Pin<Box<dyn Future<Output = ()> + Send>>) -> SubsystemResult<()> {
-		let (tx, rx) = oneshot::channel();
+	async fn spawn(&mut self, name: &'static str, s: Pin<Box<dyn Future<Output = ()> + Send>>)
+		-> SubsystemResult<()>
+	{
 		self.tx.send(ToOverseer::SpawnJob {
+			name,
 			s,
-			res: tx,
 		}).await?;
 
-		rx.await?
+		Ok(())
 	}
 
 	async fn send_message(&mut self, msg: AllMessages) -> SubsystemResult<()> {
@@ -322,7 +323,7 @@ struct OverseenSubsystem<M> {
 }
 
 /// The `Overseer` itself.
-pub struct Overseer<S: Spawn> {
+pub struct Overseer<S: SpawnNamed> {
 	/// A candidate validation subsystem.
 	candidate_validation_subsystem: OverseenSubsystem<CandidateValidationMessage>,
 
@@ -361,7 +362,7 @@ pub struct Overseer<S: Spawn> {
 	s: S,
 
 	/// Here we keep handles to spawned subsystems to be notified when they terminate.
-	running_subsystems: FuturesUnordered<RemoteHandle<()>>,
+	running_subsystems: FuturesUnordered<BoxFuture<'static, ()>>,
 
 	/// Gather running subsystms' outbound streams into one.
 	running_subsystems_rx: StreamUnordered<mpsc::Receiver<ToOverseer>>,
@@ -416,7 +417,7 @@ pub struct AllSubsystems<CV, CB, CS, SD, AD, BD, P, PoVD, RA, AS, NB> {
 
 impl<S> Overseer<S>
 where
-	S: Spawn,
+	S: SpawnNamed,
 {
 	/// Create a new intance of the `Overseer` with a fixed set of [`Subsystem`]s.
 	///
@@ -467,16 +468,19 @@ where
 	///         self,
 	///         mut ctx: C,
 	///     ) -> SpawnedSubsystem {
-	///         SpawnedSubsystem(Box::pin(async move {
-	///             loop {
-	///                 Delay::new(Duration::from_secs(1)).await;
-	///             }
-	///         }))
+	///         SpawnedSubsystem {
+	///             name: "validation-subsystem",
+	///             future: Box::pin(async move {
+	///                 loop {
+	///                     Delay::new(Duration::from_secs(1)).await;
+	///                 }
+	///             }),
+	///         }
 	///     }
 	/// }
 	///
 	/// # fn main() { executor::block_on(async move {
-	/// let spawner = executor::ThreadPool::new().unwrap();
+	/// let spawner = sp_core::testing::SpawnBlockingExecutor::new();
 	/// let all_subsystems = AllSubsystems {
 	///     candidate_validation: ValidationSubsystem,
 	///     candidate_backing: DummySubsystem,
@@ -737,10 +741,8 @@ where
 			) {
 				match msg {
 					ToOverseer::SubsystemMessage(msg) => self.route_message(msg).await,
-					ToOverseer::SpawnJob { s, res } => {
-						let s = self.spawn_job(s);
-
-						let _ = res.send(s);
+					ToOverseer::SpawnJob { name, s } => {
+						self.spawn_job(name, s);
 					}
 				}
 			}
@@ -897,26 +899,33 @@ where
 		}
 	}
 
-	fn spawn_job(&mut self, j: BoxFuture<'static, ()>) -> SubsystemResult<()> {
-		self.s.spawn(j).map_err(|_| SubsystemError)
+	fn spawn_job(&mut self, name: &'static str, j: BoxFuture<'static, ()>) {
+		self.s.spawn(name, j);
 	}
 }
 
-fn spawn<S: Spawn, M: Send + 'static>(
+fn spawn<S: SpawnNamed, M: Send + 'static>(
 	spawner: &mut S,
-	futures: &mut FuturesUnordered<RemoteHandle<()>>,
+	futures: &mut FuturesUnordered<BoxFuture<'static, ()>>,
 	streams: &mut StreamUnordered<mpsc::Receiver<ToOverseer>>,
 	s: impl Subsystem<OverseerSubsystemContext<M>>,
 ) -> SubsystemResult<OverseenSubsystem<M>> {
 	let (to_tx, to_rx) = mpsc::channel(CHANNEL_CAPACITY);
 	let (from_tx, from_rx) = mpsc::channel(CHANNEL_CAPACITY);
 	let ctx = OverseerSubsystemContext { rx: to_rx, tx: from_tx };
-	let f = s.start(ctx);
+	let SpawnedSubsystem { future, name } = s.start(ctx);
 
-	let handle = spawner.spawn_with_handle(f.0)?;
+	let (tx, rx) = oneshot::channel();
+
+	let fut = Box::pin(async move {
+		future.await;
+		let _ = tx.send(());
+	});
+
+	spawner.spawn(name, fut);
 
 	streams.push(from_rx);
-	futures.push(handle);
+	futures.push(Box::pin(rx.map(|_| ())));
 
 	let instance = Some(SubsystemInstance {
 		tx: to_tx,
@@ -944,21 +953,24 @@ mod tests {
 	{
 		fn start(self, mut ctx: C) -> SpawnedSubsystem {
 			let mut sender = self.0;
-			SpawnedSubsystem(Box::pin(async move {
-				let mut i = 0;
-				loop {
-					match ctx.recv().await {
-						Ok(FromOverseer::Communication { .. }) => {
-							let _ = sender.send(i).await;
-							i += 1;
-							continue;
+			SpawnedSubsystem {
+				name: "test-subsystem-1",
+				future: Box::pin(async move {
+					let mut i = 0;
+					loop {
+						match ctx.recv().await {
+							Ok(FromOverseer::Communication { .. }) => {
+								let _ = sender.send(i).await;
+								i += 1;
+								continue;
+							}
+							Ok(FromOverseer::Signal(OverseerSignal::Conclude)) => return,
+							Err(_) => return,
+							_ => (),
 						}
-						Ok(FromOverseer::Signal(OverseerSignal::Conclude)) => return,
-						Err(_) => return,
-						_ => (),
 					}
-				}
-			}))
+				}),
+			}
 		}
 	}
 
@@ -969,39 +981,42 @@ mod tests {
 	{
 		fn start(self, mut ctx: C) -> SpawnedSubsystem {
 			let sender = self.0.clone();
-			SpawnedSubsystem(Box::pin(async move {
-				let _sender = sender;
-				let mut c: usize = 0;
-				loop {
-					if c < 10 {
-						let (tx, _) = oneshot::channel();
-						ctx.send_message(
-							AllMessages::CandidateValidation(
-								CandidateValidationMessage::ValidateFromChainState(
-									Default::default(),
-									PoV {
-										block_data: BlockData(Vec::new()),
-									}.into(),
-									tx,
+			SpawnedSubsystem {
+				name: "test-subsystem-2",
+				future: Box::pin(async move {
+					let _sender = sender;
+					let mut c: usize = 0;
+					loop {
+						if c < 10 {
+							let (tx, _) = oneshot::channel();
+							ctx.send_message(
+								AllMessages::CandidateValidation(
+									CandidateValidationMessage::ValidateFromChainState(
+										Default::default(),
+										PoV {
+											block_data: BlockData(Vec::new()),
+										}.into(),
+										tx,
+									)
 								)
-							)
-						).await.unwrap();
-						c += 1;
-						continue;
-					}
-					match ctx.try_recv().await {
-						Ok(Some(FromOverseer::Signal(OverseerSignal::Conclude))) => {
-							break;
-						}
-						Ok(Some(_)) => {
+							).await.unwrap();
+							c += 1;
 							continue;
 						}
-						Err(_) => return,
-						_ => (),
+						match ctx.try_recv().await {
+							Ok(Some(FromOverseer::Signal(OverseerSignal::Conclude))) => {
+								break;
+							}
+							Ok(Some(_)) => {
+								continue;
+							}
+							Err(_) => return,
+							_ => (),
+						}
+						pending!();
 					}
-					pending!();
-				}
-			}))
+				}),
+			}
 		}
 	}
 
@@ -1011,16 +1026,19 @@ mod tests {
 		where C: SubsystemContext<Message=CandidateBackingMessage>
 	{
 		fn start(self, mut _ctx: C) -> SpawnedSubsystem {
-			SpawnedSubsystem(Box::pin(async move {
-				// Do nothing and exit.
-			}))
+			SpawnedSubsystem {
+				name: "test-subsystem-4",
+				future: Box::pin(async move {
+					// Do nothing and exit.
+				}),
+			}
 		}
 	}
 
 	// Checks that a minimal configuration of two jobs can run and exchange messages.
 	#[test]
 	fn overseer_works() {
-		let spawner = executor::ThreadPool::new().unwrap();
+		let spawner = sp_core::testing::SpawnBlockingExecutor::new();
 
 		executor::block_on(async move {
 			let (s1_tx, mut s1_rx) = mpsc::channel(64);
@@ -1084,7 +1102,7 @@ mod tests {
 	// Should immediately conclude the overseer itself with an error.
 	#[test]
 	fn overseer_panics_on_subsystem_exit() {
-		let spawner = executor::ThreadPool::new().unwrap();
+		let spawner = sp_core::testing::SpawnBlockingExecutor::new();
 
 		executor::block_on(async move {
 			let (s1_tx, _) = mpsc::channel(64);
@@ -1124,21 +1142,24 @@ mod tests {
 		fn start(self, mut ctx: C) -> SpawnedSubsystem {
 			let mut sender = self.0.clone();
 
-			SpawnedSubsystem(Box::pin(async move {
-				loop {
-					match ctx.try_recv().await {
-						Ok(Some(FromOverseer::Signal(OverseerSignal::Conclude))) => break,
-						Ok(Some(FromOverseer::Signal(s))) => {
-							sender.send(s).await.unwrap();
-							continue;
-						},
-						Ok(Some(_)) => continue,
-						Err(_) => return,
-						_ => (),
+			SpawnedSubsystem {
+				name: "test-subsystem-5",
+				future: Box::pin(async move {
+					loop {
+						match ctx.try_recv().await {
+							Ok(Some(FromOverseer::Signal(OverseerSignal::Conclude))) => break,
+							Ok(Some(FromOverseer::Signal(s))) => {
+								sender.send(s).await.unwrap();
+								continue;
+							},
+							Ok(Some(_)) => continue,
+							Err(_) => return,
+							_ => (),
+						}
+						pending!();
 					}
-					pending!();
-				}
-			}))
+				}),
+			}
 		}
 	}
 
@@ -1150,21 +1171,24 @@ mod tests {
 		fn start(self, mut ctx: C) -> SpawnedSubsystem {
 			let mut sender = self.0.clone();
 
-			SpawnedSubsystem(Box::pin(async move {
-				loop {
-					match ctx.try_recv().await {
-						Ok(Some(FromOverseer::Signal(OverseerSignal::Conclude))) => break,
-						Ok(Some(FromOverseer::Signal(s))) => {
-							sender.send(s).await.unwrap();
-							continue;
-						},
-						Ok(Some(_)) => continue,
-						Err(_) => return,
-						_ => (),
+			SpawnedSubsystem {
+				name: "test-subsystem-6",
+				future: Box::pin(async move {
+					loop {
+						match ctx.try_recv().await {
+							Ok(Some(FromOverseer::Signal(OverseerSignal::Conclude))) => break,
+							Ok(Some(FromOverseer::Signal(s))) => {
+								sender.send(s).await.unwrap();
+								continue;
+							},
+							Ok(Some(_)) => continue,
+							Err(_) => return,
+							_ => (),
+						}
+						pending!();
 					}
-					pending!();
-				}
-			}))
+				}),
+			}
 		}
 	}
 
@@ -1172,7 +1196,7 @@ mod tests {
 	// notifications on imported blocks triggers expected `StartWork` and `StopWork` heartbeats.
 	#[test]
 	fn overseer_start_stop_works() {
-		let spawner = executor::ThreadPool::new().unwrap();
+		let spawner = sp_core::testing::SpawnBlockingExecutor::new();
 
 		executor::block_on(async move {
 			let first_block_hash = [1; 32].into();
@@ -1267,7 +1291,7 @@ mod tests {
 	// notifications on imported blocks triggers expected `StartWork` and `StopWork` heartbeats.
 	#[test]
 	fn overseer_finalize_works() {
-		let spawner = executor::ThreadPool::new().unwrap();
+		let spawner = sp_core::testing::SpawnBlockingExecutor::new();
 
 		executor::block_on(async move {
 			let first_block_hash = [1; 32].into();

polkadot/node/primitives/Cargo.toml

@@ -11,3 +11,4 @@ polkadot-statement-table = { path = "../../statement-table" }
 parity-scale-codec = { version = "1.3.0", default-features = false, features = ["derive"] }
 runtime_primitives = { package = "sp-runtime", git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 async-trait = "0.1"
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }

polkadot/node/primitives/src/lib.rs

@@ -35,6 +35,8 @@ use polkadot_statement_table::{
 	v1::Misbehavior as TableMisbehavior,
 };
 
+pub use sp_core::traits::SpawnNamed;
+
 /// A statement, where the candidate receipt is included in the `Seconded` variant.
 ///
 /// This is the committed candidate receipt instead of the bare candidate receipt. As such,

polkadot/node/service/src/lib.rs

@@ -33,6 +33,7 @@ use polkadot_overseer::{self as overseer, AllSubsystems, BlockInfo, Overseer, Ov
 use polkadot_subsystem::DummySubsystem;
 use polkadot_node_core_proposer::ProposerFactory;
 use sp_trie::PrefixedMemoryDB;
+use sp_core::traits::SpawnNamed;
 pub use service::{
 	Role, PruningMode, TransactionPoolOptions, Error, RuntimeGenesis,
 	TFullClient, TLightClient, TFullBackend, TLightBackend, TFullCallExecutor, TLightCallExecutor,
@@ -269,7 +270,7 @@ macro_rules! new_full_start {
 	}}
 }
 
-fn real_overseer<S: futures::task::Spawn>(
+fn real_overseer<S: SpawnNamed>(
 	leaves: impl IntoIterator<Item = BlockInfo>,
 	s: S,
 ) -> Result<(Overseer<S>, OverseerHandler), ServiceError> {

polkadot/node/subsystem/src/lib.rs

@@ -101,7 +101,12 @@ impl From<std::convert::Infallible> for SubsystemError {
 /// An asynchronous subsystem task..
 ///
 /// In essence it's just a newtype wrapping a `BoxFuture`.
-pub struct SpawnedSubsystem(pub BoxFuture<'static, ()>);
+pub struct SpawnedSubsystem {
+	/// Name of the subsystem being spawned.
+	pub name: &'static str,
+	/// The task of the subsystem being spawned.
+	pub future: BoxFuture<'static, ()>,
+}
 
 /// A `Result` type that wraps [`SubsystemError`].
 ///
@@ -130,7 +135,7 @@ pub trait SubsystemContext: Send + 'static {
 	async fn recv(&mut self) -> SubsystemResult<FromOverseer<Self::Message>>;
 
 	/// Spawn a child task on the executor.
-	async fn spawn(&mut self, s: Pin<Box<dyn Future<Output = ()> + Send>>) -> SubsystemResult<()>;
+	async fn spawn(&mut self, name: &'static str, s: Pin<Box<dyn Future<Output = ()> + Send>>) -> SubsystemResult<()>;
 
 	/// Send a direct message to some other `Subsystem`, routed based on message type.
 	async fn send_message(&mut self, msg: AllMessages) -> SubsystemResult<()>;
@@ -159,7 +164,7 @@ pub struct DummySubsystem;
 
 impl<C: SubsystemContext> Subsystem<C> for DummySubsystem {
 	fn start(self, mut ctx: C) -> SpawnedSubsystem {
-		SpawnedSubsystem(Box::pin(async move {
+		let future = Box::pin(async move {
 			loop {
 				match ctx.recv().await {
 					Ok(FromOverseer::Signal(OverseerSignal::Conclude)) => return,
@@ -167,6 +172,11 @@ impl<C: SubsystemContext> Subsystem<C> for DummySubsystem {
 					_ => continue,
 				}
 			}
-		}))
+		});
+
+		SpawnedSubsystem {
+			name: "DummySubsystem",
+			future,
+		}
 	}
 }

polkadot/node/subsystem/src/util.rs

@@ -30,7 +30,7 @@ use futures::{
 	prelude::*,
 	select,
 	stream::Stream,
-	task::{self, Spawn, SpawnError, SpawnExt},
+	task,
 };
 use futures_timer::Delay;
 use keystore::KeyStorePtr;
@@ -40,7 +40,10 @@ use polkadot_primitives::v1::{
 	EncodeAs, Hash, HeadData, Id as ParaId, Signed, SigningContext,
 	ValidatorId, ValidatorIndex, ValidatorPair,
 };
-use sp_core::Pair;
+use sp_core::{
+	Pair,
+	traits::SpawnNamed,
+};
 use std::{
 	collections::HashMap,
 	convert::{TryFrom, TryInto},
@@ -64,9 +67,6 @@ pub enum Error {
 	/// Attempted to send on a MPSC channel which has been canceled
 	#[from]
 	Mpsc(mpsc::SendError),
-	/// Attempted to spawn a new task, and failed
-	#[from]
-	Spawn(SpawnError),
 	/// Attempted to convert from an AllMessages to a FromJob, and failed.
 	SenderConversion(String),
 	/// The local node is not a validator.
@@ -358,7 +358,7 @@ pub struct Jobs<Spawner, Job: JobTrait> {
 	job: std::marker::PhantomData<Job>,
 }
 
-impl<Spawner: Spawn, Job: JobTrait> Jobs<Spawner, Job> {
+impl<Spawner: SpawnNamed, Job: JobTrait> Jobs<Spawner, Job> {
 	/// Create a new Jobs manager which handles spawning appropriate jobs.
 	pub fn new(spawner: Spawner) -> Self {
 		Self {
@@ -391,7 +391,7 @@ impl<Spawner: Spawn, Job: JobTrait> Jobs<Spawner, Job> {
 			let _ = future.await;
 			let _ = finished_tx.send(());
 		};
-		self.spawner.spawn(future)?;
+		self.spawner.spawn(Job::NAME, future.boxed());
 
 		// this handle lets us remove the appropriate receiver from self.outgoing_msgs
 		// when it's time to stop the job.
@@ -444,7 +444,7 @@ impl<Spawner, Job: JobTrait> PinnedDrop for Jobs<Spawner, Job> {
 
 impl<Spawner, Job> Stream for Jobs<Spawner, Job>
 where
-	Spawner: Spawn,
+	Spawner: SpawnNamed,
 	Job: JobTrait,
 {
 	type Item = Job::FromJob;
@@ -476,7 +476,7 @@ pub struct JobManager<Spawner, Context, Job: JobTrait> {
 
 impl<Spawner, Context, Job> JobManager<Spawner, Context, Job>
 where
-	Spawner: Spawn + Clone + Send + Unpin,
+	Spawner: SpawnNamed + Clone + Send + Unpin,
 	Context: SubsystemContext,
 	Job: JobTrait,
 	Job::RunArgs: Clone,
@@ -595,7 +595,7 @@ where
 
 impl<Spawner, Context, Job> Subsystem<Context> for JobManager<Spawner, Context, Job>
 where
-	Spawner: Spawn + Send + Clone + Unpin + 'static,
+	Spawner: SpawnNamed + Send + Clone + Unpin + 'static,
 	Context: SubsystemContext,
 	<Context as SubsystemContext>::Message: Into<Job::ToJob>,
 	Job: JobTrait + Send,
@@ -606,8 +606,13 @@ where
 		let spawner = self.spawner.clone();
 		let run_args = self.run_args.clone();
 
-		SpawnedSubsystem(Box::pin(async move {
+		let future = Box::pin(async move {
 			Self::run(ctx, run_args, spawner).await;
-		}))
+		});
+
+		SpawnedSubsystem {
+			name: "JobManager",
+			future,
+		}
 	}
 }

polkadot/node/test-helpers/subsystem/Cargo.toml

@@ -10,3 +10,4 @@ futures = "0.3.5"
 async-trait = "0.1"
 polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem" }
 parking_lot = "0.10.0"
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }

polkadot/node/test-helpers/subsystem/src/lib.rs

@@ -21,9 +21,9 @@ use polkadot_subsystem::messages::AllMessages;
 
 use futures::prelude::*;
 use futures::channel::mpsc;
-use futures::task::{Spawn, SpawnExt};
 use futures::poll;
 use parking_lot::Mutex;
+use sp_core::traits::SpawnNamed;
 
 use std::convert::Infallible;
 use std::pin::Pin;
@@ -155,7 +155,7 @@ pub struct TestSubsystemContext<M, S> {
 }
 
 #[async_trait::async_trait]
-impl<M: Send + 'static, S: Spawn + Send + 'static> SubsystemContext for TestSubsystemContext<M, S> {
+impl<M: Send + 'static, S: SpawnNamed + Send + 'static> SubsystemContext for TestSubsystemContext<M, S> {
 	type Message = M;
 
 	async fn try_recv(&mut self) -> Result<Option<FromOverseer<M>>, ()> {
@@ -170,8 +170,11 @@ impl<M: Send + 'static, S: Spawn + Send + 'static> SubsystemContext for TestSubs
 		self.rx.next().await.ok_or(SubsystemError)
 	}
 
-	async fn spawn(&mut self, s: Pin<Box<dyn Future<Output = ()> + Send>>) -> SubsystemResult<()> {
-		self.spawn.spawn(s).map_err(Into::into)
+	async fn spawn(&mut self, name: &'static str, s: Pin<Box<dyn Future<Output = ()> + Send>>)
+		-> SubsystemResult<()>
+	{
+		self.spawn.spawn(name, s);
+		Ok(())
 	}
 
 	async fn send_message(&mut self, msg: AllMessages) -> SubsystemResult<()> {