implement remaining subsystem metrics (#1770)

* overseer metrics: messages relayed

* provisioner metrics: cosmetic changes

* candidate selection metrics: cosmetic changes

* availability bitfields metrics

* availability distribution metrics

* PoV distribution metrics

* statement-distribution: small simplification

* statement-distribution: extract log target into a const

* statement-distribution: metrics

* address review nits

polkadot/Cargo.lock

@@ -5144,6 +5144,7 @@ dependencies = [
  "polkadot-node-primitives",
  "polkadot-node-subsystem",
  "polkadot-node-subsystem-test-helpers",
+ "polkadot-node-subsystem-util",
  "polkadot-primitives",
  "sp-core",
  "sp-runtime",
@@ -5499,6 +5500,7 @@ dependencies = [
  "polkadot-node-primitives",
  "polkadot-node-subsystem",
  "polkadot-node-subsystem-test-helpers",
+ "polkadot-node-subsystem-util",
  "polkadot-primitives",
  "sp-core",
  "sp-keyring",

polkadot/node/core/candidate-selection/src/lib.rs

@@ -282,18 +282,18 @@ impl CandidateSelectionJob {
 			candidate_receipt
 		);
 
-		let succeeded =
+		let result =
 			if let Err(err) = forward_invalidity_note(received_from, &mut self.sender).await {
 				log::warn!(
 					target: TARGET,
 					"failed to forward invalidity note: {:?}",
 					err
 				);
-				false
+				Err(())
 			} else {
-				true
+				Ok(())
 			};
-		self.metrics.on_invalid_selection(succeeded);
+		self.metrics.on_invalid_selection(result);
 	}
 }
 
@@ -363,11 +363,11 @@ async fn second_candidate(
 	{
 		Err(err) => {
 			log::warn!(target: TARGET, "failed to send a seconding message");
-			metrics.on_second(false);
+			metrics.on_second(Err(()));
 			Err(err.into())
 		}
 		Ok(_) => {
-			metrics.on_second(true);
+			metrics.on_second(Ok(()));
 			Ok(())
 		}
 	}
@@ -391,21 +391,21 @@ struct MetricsInner {
 	invalid_selections: prometheus::CounterVec<prometheus::U64>,
 }
 
-/// Candidate backing metrics.
+/// Candidate selection metrics.
 #[derive(Default, Clone)]
 pub struct Metrics(Option<MetricsInner>);
 
 impl Metrics {
-	fn on_second(&self, succeeded: bool) {
+	fn on_second(&self, result: Result<(), ()>) {
 		if let Some(metrics) = &self.0 {
-			let label = if succeeded { "succeeded" } else { "failed" };
+			let label = if result.is_ok() { "succeeded" } else { "failed" };
 			metrics.seconds.with_label_values(&[label]).inc();
 		}
 	}
 
-	fn on_invalid_selection(&self, succeeded: bool) {
+	fn on_invalid_selection(&self, result: Result<(), ()>) {
 		if let Some(metrics) = &self.0 {
-			let label = if succeeded { "succeeded" } else { "failed" };
+			let label = if result.is_ok() { "succeeded" } else { "failed" };
 			metrics.invalid_selections.with_label_values(&[label]).inc();
 		}
 	}

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

@@ -196,9 +196,9 @@ impl ProvisioningJob {
 					.await
 					{
 						log::warn!(target: "provisioner", "failed to assemble or send inherent data: {:?}", err);
-						self.metrics.on_inherent_data_request(false);
+						self.metrics.on_inherent_data_request(Err(()));
 					} else {
-						self.metrics.on_inherent_data_request(true);
+						self.metrics.on_inherent_data_request(Ok(()));
 					}
 				}
 				ToJob::Provisioner(RequestBlockAuthorshipData(_, sender)) => {
@@ -467,17 +467,16 @@ struct MetricsInner {
 	inherent_data_requests: prometheus::CounterVec<prometheus::U64>,
 }
 
-/// Candidate backing metrics.
+/// Provisioner metrics.
 #[derive(Default, Clone)]
 pub struct Metrics(Option<MetricsInner>);
 
 impl Metrics {
-	fn on_inherent_data_request(&self, succeeded: bool) {
+	fn on_inherent_data_request(&self, response: Result<(), ()>) {
 		if let Some(metrics) = &self.0 {
-			if succeeded {
-				metrics.inherent_data_requests.with_label_values(&["succeded"]).inc();
-			} else {
-				metrics.inherent_data_requests.with_label_values(&["failed"]).inc();
+			match response {
+				Ok(()) => metrics.inherent_data_requests.with_label_values(&["succeded"]).inc(),
+				Err(()) => metrics.inherent_data_requests.with_label_values(&["failed"]).inc(),
 			}
 		}
 	}

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

@@ -49,6 +49,9 @@ use polkadot_subsystem::{
 	ActiveLeavesUpdate, FromOverseer, OverseerSignal, SpawnedSubsystem, Subsystem,
 	SubsystemContext, SubsystemError,
 };
+use polkadot_node_subsystem_util::{
+	metrics::{self, prometheus},
+};
 use polkadot_node_network_protocol::{
 	v1 as protocol_v1, View, ReputationChange as Rep, PeerId,
 	NetworkBridgeEvent,
@@ -292,6 +295,7 @@ async fn handle_network_msg<Context>(
 	ctx: &mut Context,
 	keystore: KeyStorePtr,
 	state: &mut ProtocolState,
+	metrics: &Metrics,
 	bridge_message: NetworkBridgeEvent<protocol_v1::AvailabilityDistributionMessage>,
 ) -> Result<()>
 where
@@ -307,10 +311,10 @@ where
 			state.peer_views.remove(&peerid);
 		}
 		NetworkBridgeEvent::PeerViewChange(peerid, view) => {
-			handle_peer_view_change(ctx, state, peerid, view).await?;
+			handle_peer_view_change(ctx, state, peerid, view, metrics).await?;
 		}
 		NetworkBridgeEvent::OurViewChange(view) => {
-			handle_our_view_change(ctx, keystore, state, view).await?;
+			handle_our_view_change(ctx, keystore, state, view, metrics).await?;
 		}
 		NetworkBridgeEvent::PeerMessage(remote, msg) => {
 			let gossiped_availability = match msg {
@@ -318,7 +322,7 @@ where
 					AvailabilityGossipMessage { candidate_hash, erasure_chunk: chunk }
 			};
 
-			process_incoming_peer_message(ctx, state, remote, gossiped_availability).await?;
+			process_incoming_peer_message(ctx, state, remote, gossiped_availability, metrics).await?;
 		}
 	}
 	Ok(())
@@ -331,6 +335,7 @@ async fn handle_our_view_change<Context>(
 	keystore: KeyStorePtr,
 	state: &mut ProtocolState,
 	view: View,
+	metrics: &Metrics,
 ) -> Result<()>
 where
 	Context: SubsystemContext<Message = AvailabilityDistributionMessage>,
@@ -426,7 +431,7 @@ where
 				erasure_chunk,
 			};
 
-			send_tracked_gossip_message_to_peers(ctx, per_candidate, peers, message).await?;
+			send_tracked_gossip_message_to_peers(ctx, per_candidate, metrics, peers, message).await?;
 		}
 	}
 
@@ -442,31 +447,34 @@ where
 async fn send_tracked_gossip_message_to_peers<Context>(
 	ctx: &mut Context,
 	per_candidate: &mut PerCandidate,
+	metrics: &Metrics,
 	peers: Vec<PeerId>,
 	message: AvailabilityGossipMessage,
 ) -> Result<()>
 where
 	Context: SubsystemContext<Message = AvailabilityDistributionMessage>,
 {
-	send_tracked_gossip_messages_to_peers(ctx, per_candidate, peers, iter::once(message)).await
+	send_tracked_gossip_messages_to_peers(ctx, per_candidate, metrics, peers, iter::once(message)).await
 }
 
 #[inline(always)]
 async fn send_tracked_gossip_messages_to_peer<Context>(
 	ctx: &mut Context,
 	per_candidate: &mut PerCandidate,
+	metrics: &Metrics,
 	peer: PeerId,
 	message_iter: impl IntoIterator<Item = AvailabilityGossipMessage>,
 ) -> Result<()>
 where
 	Context: SubsystemContext<Message = AvailabilityDistributionMessage>,
 {
-	send_tracked_gossip_messages_to_peers(ctx, per_candidate, vec![peer], message_iter).await
+	send_tracked_gossip_messages_to_peers(ctx, per_candidate, metrics, vec![peer], message_iter).await
 }
 
 async fn send_tracked_gossip_messages_to_peers<Context>(
 	ctx: &mut Context,
 	per_candidate: &mut PerCandidate,
+	metrics: &Metrics,
 	peers: Vec<PeerId>,
 	message_iter: impl IntoIterator<Item = AvailabilityGossipMessage>,
 ) -> Result<()>
@@ -503,6 +511,8 @@ where
 		))
 		.await
 		.map_err::<Error, _>(Into::into)?;
+
+		metrics.on_chunk_distributed();
 	}
 
 	Ok(())
@@ -515,6 +525,7 @@ async fn handle_peer_view_change<Context>(
 	state: &mut ProtocolState,
 	origin: PeerId,
 	view: View,
+	metrics: &Metrics,
 ) -> Result<()>
 where
 	Context: SubsystemContext<Message = AvailabilityDistributionMessage>,
@@ -560,7 +571,7 @@ where
 			.cloned()
 			.collect::<HashSet<_>>();
 
-		send_tracked_gossip_messages_to_peer(ctx, per_candidate, origin.clone(), messages).await?;
+		send_tracked_gossip_messages_to_peer(ctx, per_candidate, metrics, origin.clone(), messages).await?;
 	}
 	Ok(())
 }
@@ -588,6 +599,7 @@ async fn process_incoming_peer_message<Context>(
 	state: &mut ProtocolState,
 	origin: PeerId,
 	message: AvailabilityGossipMessage,
+	metrics: &Metrics,
 ) -> Result<()>
 where
 	Context: SubsystemContext<Message = AvailabilityDistributionMessage>,
@@ -694,13 +706,15 @@ where
 		.collect::<Vec<_>>();
 
 	// gossip that message to interested peers
-	send_tracked_gossip_message_to_peers(ctx, per_candidate, peers, message).await
+	send_tracked_gossip_message_to_peers(ctx, per_candidate, metrics, peers, message).await
 }
 
 /// The bitfield distribution subsystem.
 pub struct AvailabilityDistributionSubsystem {
 	/// Pointer to a keystore, which is required for determining this nodes validator index.
 	keystore: KeyStorePtr,
+	/// Prometheus metrics.
+	metrics: Metrics,
 }
 
 impl AvailabilityDistributionSubsystem {
@@ -708,8 +722,8 @@ impl AvailabilityDistributionSubsystem {
 	const K: usize = 3;
 
 	/// Create a new instance of the availability distribution.
-	pub fn new(keystore: KeyStorePtr) -> Self {
-		Self { keystore }
+	pub fn new(keystore: KeyStorePtr, metrics: Metrics) -> Self {
+		Self { keystore, metrics }
 	}
 
 	/// Start processing work as passed on from the Overseer.
@@ -729,7 +743,8 @@ impl AvailabilityDistributionSubsystem {
 						&mut ctx,
 						self.keystore.clone(),
 						&mut state,
-						event
+						&self.metrics,
+						event,
 					).await {
 						warn!(
 							target: TARGET,
@@ -1073,5 +1088,37 @@ where
 }
 
 
+#[derive(Clone)]
+struct MetricsInner {
+	gossipped_availability_chunks: prometheus::Counter<prometheus::U64>,
+}
+
+/// Availability Distribution metrics.
+#[derive(Default, Clone)]
+pub struct Metrics(Option<MetricsInner>);
+
+impl Metrics {
+	fn on_chunk_distributed(&self) {
+		if let Some(metrics) = &self.0 {
+			metrics.gossipped_availability_chunks.inc();
+		}
+	}
+}
+
+impl metrics::Metrics for Metrics {
+	fn try_register(registry: &prometheus::Registry) -> std::result::Result<Self, prometheus::PrometheusError> {
+		let metrics = MetricsInner {
+			gossipped_availability_chunks: prometheus::register(
+				prometheus::Counter::new(
+					"parachain_gossipped_availability_chunks_total",
+					"Number of availability chunks gossipped to other peers."
+				)?,
+				registry,
+			)?,
+		};
+		Ok(Metrics(Some(metrics)))
+	}
+}
+
 #[cfg(test)]
 mod tests;

polkadot/node/network/availability-distribution/src/tests.rs

@@ -72,7 +72,7 @@ fn test_harness<T: Future<Output = ()>>(
 
 	let (context, virtual_overseer) = test_helpers::make_subsystem_context(pool.clone());
 
-	let subsystem = AvailabilityDistributionSubsystem::new(keystore);
+	let subsystem = AvailabilityDistributionSubsystem::new(keystore, Default::default());
 	let subsystem = subsystem.run(context);
 
 	let test_fut = test(TestHarness { virtual_overseer });

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

@@ -13,7 +13,7 @@ codec = { package="parity-scale-codec", version = "1.3.4" }
 node-primitives = { package = "polkadot-node-primitives", path = "../../primitives" }
 polkadot-primitives = { path = "../../../primitives" }
 polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem" }
-polkadot-node-subsystem-util = { package = "polkadot-node-subsystem-util", path = "../../subsystem-util" }
+polkadot-node-subsystem-util = { path = "../../subsystem-util" }
 polkadot-network-bridge = { path = "../../network/bridge" }
 polkadot-node-network-protocol = { path = "../../network/protocol" }
 sc-network = { git = "https://github.com/paritytech/substrate", branch = "master" }

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

@@ -28,6 +28,9 @@ use polkadot_subsystem::messages::*;
 use polkadot_subsystem::{
 	ActiveLeavesUpdate, FromOverseer, OverseerSignal, SpawnedSubsystem, Subsystem, SubsystemContext, SubsystemResult,
 };
+use polkadot_node_subsystem_util::{
+	metrics::{self, prometheus},
+};
 use polkadot_primitives::v1::{Hash, SignedAvailabilityBitfield, SigningContext, ValidatorId};
 use polkadot_node_network_protocol::{v1 as protocol_v1, PeerId, NetworkBridgeEvent, View, ReputationChange};
 use std::collections::{HashMap, HashSet};
@@ -130,11 +133,18 @@ impl PerRelayParentData {
 const TARGET: &'static str = "bitd";
 
 /// The bitfield distribution subsystem.
-pub struct BitfieldDistribution;
+pub struct BitfieldDistribution {
+	metrics: Metrics,
+}
 
 impl BitfieldDistribution {
+	/// Create a new instance of the `BitfieldDistribution` subsystem.
+	pub fn new(metrics: Metrics) -> Self {
+		Self { metrics }
+	}
+
 	/// Start processing work as passed on from the Overseer.
-	async fn run<Context>(mut ctx: Context) -> SubsystemResult<()>
+	async fn run<Context>(self, mut ctx: Context) -> SubsystemResult<()>
 	where
 		Context: SubsystemContext<Message = BitfieldDistributionMessage>,
 	{
@@ -147,7 +157,7 @@ impl BitfieldDistribution {
 					msg: BitfieldDistributionMessage::DistributeBitfield(hash, signed_availability),
 				} => {
 					trace!(target: TARGET, "Processing DistributeBitfield");
-					handle_bitfield_distribution(&mut ctx, &mut state, hash, signed_availability)
+					handle_bitfield_distribution(&mut ctx, &mut state, &self.metrics, hash, signed_availability)
 						.await?;
 				}
 				FromOverseer::Communication {
@@ -155,7 +165,7 @@ impl BitfieldDistribution {
 				} => {
 					trace!(target: TARGET, "Processing NetworkMessage");
 					// a network message was received
-					if let Err(e) = handle_network_msg(&mut ctx, &mut state, event).await {
+					if let Err(e) = handle_network_msg(&mut ctx, &mut state, &self.metrics, event).await {
 						warn!(target: TARGET, "Failed to handle incomming network messages: {:?}", e);
 					}
 				}
@@ -221,6 +231,7 @@ where
 async fn handle_bitfield_distribution<Context>(
 	ctx: &mut Context,
 	state: &mut ProtocolState,
+	metrics: &Metrics,
 	relay_parent: Hash,
 	signed_availability: SignedAvailabilityBitfield,
 ) -> SubsystemResult<()>
@@ -262,6 +273,8 @@ where
 
 	relay_message(ctx, job_data, peer_views, validator, msg).await?;
 
+	metrics.on_own_bitfield_gossipped();
+
 	Ok(())
 }
 
@@ -330,6 +343,7 @@ where
 async fn process_incoming_peer_message<Context>(
 	ctx: &mut Context,
 	state: &mut ProtocolState,
+	metrics: &Metrics,
 	origin: PeerId,
 	message: BitfieldGossipMessage,
 ) -> SubsystemResult<()>
@@ -388,6 +402,7 @@ where
 		.check_signature(&signing_context, &validator)
 		.is_ok()
 	{
+		metrics.on_bitfield_received();
 		let one_per_validator = &mut (job_data.one_per_validator);
 
 		// only relay_message a message of a validator once
@@ -415,6 +430,7 @@ where
 async fn handle_network_msg<Context>(
 	ctx: &mut Context,
 	state: &mut ProtocolState,
+	metrics: &Metrics,
 	bridge_message: NetworkBridgeEvent<protocol_v1::BitfieldDistributionMessage>,
 ) -> SubsystemResult<()>
 where
@@ -443,7 +459,7 @@ where
 						relay_parent,
 						signed_availability: bitfield,
 					};
-					process_incoming_peer_message(ctx, state, remote, gossiped_bitfield).await?;
+					process_incoming_peer_message(ctx, state, metrics, remote, gossiped_bitfield).await?;
 				}
 			}
 		}
@@ -564,7 +580,7 @@ where
 	fn start(self, ctx: C) -> SpawnedSubsystem {
 		SpawnedSubsystem {
 			name: "bitfield-distribution-subsystem",
-			future: Box::pin(async move { Self::run(ctx) }.map(|_| ())),
+			future: Box::pin(async move { Self::run(self, ctx) }.map(|_| ())),
 		}
 	}
 }
@@ -605,6 +621,53 @@ where
 	}
 }
 
+#[derive(Clone)]
+struct MetricsInner {
+	gossipped_own_availability_bitfields: prometheus::Counter<prometheus::U64>,
+	received_availability_bitfields: prometheus::Counter<prometheus::U64>,
+}
+
+/// Bitfield Distribution metrics.
+#[derive(Default, Clone)]
+pub struct Metrics(Option<MetricsInner>);
+
+impl Metrics {
+	fn on_own_bitfield_gossipped(&self) {
+		if let Some(metrics) = &self.0 {
+			metrics.gossipped_own_availability_bitfields.inc();
+		}
+	}
+
+	fn on_bitfield_received(&self) {
+		if let Some(metrics) = &self.0 {
+			metrics.received_availability_bitfields.inc();
+		}
+	}
+}
+
+impl metrics::Metrics for Metrics {
+	fn try_register(registry: &prometheus::Registry) -> Result<Self, prometheus::PrometheusError> {
+		let metrics = MetricsInner {
+			gossipped_own_availability_bitfields: prometheus::register(
+				prometheus::Counter::new(
+					"parachain_gossipped_own_availabilty_bitfields_total",
+					"Number of own availability bitfields sent to other peers."
+				)?,
+				registry,
+			)?,
+			received_availability_bitfields: prometheus::register(
+				prometheus::Counter::new(
+					"parachain_received_availabilty_bitfields_total",
+					"Number of valid availability bitfields received from other peers."
+				)?,
+				registry,
+			)?,
+		};
+		Ok(Metrics(Some(metrics)))
+	}
+}
+
+
 #[cfg(test)]
 mod test {
 	use super::*;
@@ -748,6 +811,7 @@ mod test {
 			launch!(handle_network_msg(
 				&mut ctx,
 				&mut state,
+				&Default::default(),
 				NetworkBridgeEvent::PeerMessage(peer_b.clone(), msg.into_network_message()),
 			));
 
@@ -801,6 +865,7 @@ mod test {
 			launch!(handle_network_msg(
 				&mut ctx,
 				&mut state,
+				&Default::default(),
 				NetworkBridgeEvent::PeerMessage(peer_b.clone(), msg.into_network_message()),
 			));
 
@@ -854,6 +919,7 @@ mod test {
 			launch!(handle_network_msg(
 				&mut ctx,
 				&mut state,
+				&Default::default(),
 				NetworkBridgeEvent::PeerMessage(
 					peer_b.clone(),
 					msg.clone().into_network_message(),
@@ -887,6 +953,7 @@ mod test {
 			launch!(handle_network_msg(
 				&mut ctx,
 				&mut state,
+				&Default::default(),
 				NetworkBridgeEvent::PeerMessage(
 					peer_a.clone(),
 					msg.clone().into_network_message(),
@@ -907,6 +974,7 @@ mod test {
 			launch!(handle_network_msg(
 				&mut ctx,
 				&mut state,
+				&Default::default(),
 				NetworkBridgeEvent::PeerMessage(
 					peer_b.clone(),
 					msg.clone().into_network_message(),
@@ -960,6 +1028,7 @@ mod test {
 			launch!(handle_network_msg(
 				&mut ctx,
 				&mut state,
+				&Default::default(),
 				NetworkBridgeEvent::PeerConnected(peer_b.clone(), ObservedRole::Full),
 			));
 
@@ -967,6 +1036,7 @@ mod test {
 			launch!(handle_network_msg(
 				&mut ctx,
 				&mut state,
+				&Default::default(),
 				NetworkBridgeEvent::PeerViewChange(peer_b.clone(), view![hash_a, hash_b]),
 			));
 
@@ -976,6 +1046,7 @@ mod test {
 			launch!(handle_network_msg(
 				&mut ctx,
 				&mut state,
+				&Default::default(),
 				NetworkBridgeEvent::PeerMessage(
 					peer_b.clone(),
 					msg.clone().into_network_message(),
@@ -1018,6 +1089,7 @@ mod test {
 			launch!(handle_network_msg(
 				&mut ctx,
 				&mut state,
+				&Default::default(),
 				NetworkBridgeEvent::PeerViewChange(peer_b.clone(), view![]),
 			));
 
@@ -1032,6 +1104,7 @@ mod test {
 			launch!(handle_network_msg(
 				&mut ctx,
 				&mut state,
+				&Default::default(),
 				NetworkBridgeEvent::PeerMessage(
 					peer_b.clone(),
 					msg.clone().into_network_message(),
@@ -1052,6 +1125,7 @@ mod test {
 			launch!(handle_network_msg(
 				&mut ctx,
 				&mut state,
+				&Default::default(),
 				NetworkBridgeEvent::PeerDisconnected(peer_b.clone()),
 			));
 
@@ -1063,6 +1137,7 @@ mod test {
 			launch!(handle_network_msg(
 				&mut ctx,
 				&mut state,
+				&Default::default(),
 				NetworkBridgeEvent::PeerMessage(
 					peer_a.clone(),
 					msg.clone().into_network_message(),

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

@@ -14,6 +14,7 @@ node-primitives = { package = "polkadot-node-primitives", path = "../../primitiv
 parity-scale-codec = "1.3.4"
 sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master" }
 polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem" }
+polkadot-node-subsystem-util = { path = "../../subsystem-util" }
 polkadot-node-network-protocol = { path = "../../network/protocol" }
 
 [dev-dependencies]

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

@@ -22,9 +22,12 @@
 use polkadot_primitives::v1::{Hash, PoV, CandidateDescriptor};
 use polkadot_subsystem::{
 	ActiveLeavesUpdate, OverseerSignal, SubsystemContext, Subsystem, SubsystemResult, FromOverseer, SpawnedSubsystem,
+	messages::{
+		PoVDistributionMessage, RuntimeApiMessage, RuntimeApiRequest, AllMessages, NetworkBridgeMessage,
+	},
 };
-use polkadot_subsystem::messages::{
-	PoVDistributionMessage, RuntimeApiMessage, RuntimeApiRequest, AllMessages, NetworkBridgeMessage,
+use polkadot_node_subsystem_util::{
+	metrics::{self, prometheus},
 };
 use polkadot_node_network_protocol::{
 	v1 as protocol_v1, ReputationChange as Rep, NetworkBridgeEvent, PeerId, View,
@@ -46,7 +49,10 @@ const BENEFIT_LATE_POV: Rep = Rep::new(10, "Peer supplied us with an awaited PoV
 	but was not the first to do so");
 
 /// The PoV Distribution Subsystem.
-pub struct PoVDistribution;
+pub struct PoVDistribution {
+	// Prometheus metrics
+	metrics: Metrics,
+}
 
 impl<C> Subsystem<C> for PoVDistribution
 	where C: SubsystemContext<Message = PoVDistributionMessage>
@@ -56,7 +62,7 @@ impl<C> Subsystem<C> for PoVDistribution
 		// within `run`.
 		SpawnedSubsystem {
 			name: "pov-distribution-subsystem",
-			future: run(ctx).map(|_| ()).boxed(),
+			future: self.run(ctx).map(|_| ()).boxed(),
 		}
 	}
 }
@@ -65,6 +71,7 @@ struct State {
 	relay_parent_state: HashMap<Hash, BlockBasedState>,
 	peer_state: HashMap<PeerId, PeerState>,
 	our_view: View,
+	metrics: Metrics,
 }
 
 struct BlockBasedState {
@@ -206,6 +213,7 @@ async fn notify_one_we_are_awaiting_many(
 async fn distribute_to_awaiting(
 	peers: &mut HashMap<PeerId, PeerState>,
 	ctx: &mut impl SubsystemContext<Message = PoVDistributionMessage>,
+	metrics: &Metrics,
 	relay_parent: Hash,
 	pov_hash: Hash,
 	pov: &PoV,
@@ -230,7 +238,11 @@ async fn distribute_to_awaiting(
 	ctx.send_message(AllMessages::NetworkBridge(NetworkBridgeMessage::SendValidationMessage(
 		peers_to_send,
 		payload,
-	))).await
+	))).await?;
+
+	metrics.on_pov_distributed();
+
+	Ok(())
 }
 
 /// Handles a `FetchPoV` message.
@@ -307,6 +319,7 @@ async fn handle_distribute(
 	distribute_to_awaiting(
 		&mut state.peer_state,
 		ctx,
+		&state.metrics,
 		relay_parent,
 		descriptor.pov_hash,
 		&*pov,
@@ -436,6 +449,7 @@ async fn handle_incoming_pov(
 	distribute_to_awaiting(
 		&mut state.peer_state,
 		ctx,
+		&state.metrics,
 		relay_parent,
 		pov_hash,
 		&*pov,
@@ -508,48 +522,91 @@ async fn handle_network_update(
 	}
 }
 
-async fn run(
-	mut ctx: impl SubsystemContext<Message = PoVDistributionMessage>,
-) -> SubsystemResult<()> {
-	let mut state = State {
-		relay_parent_state: HashMap::new(),
-		peer_state: HashMap::new(),
-		our_view: View(Vec::new()),
-	};
+impl PoVDistribution {
+	/// Create a new instance of `PovDistribution`.
+	pub fn new(metrics: Metrics) -> Self {
+		Self { metrics }
+	}
 
-	loop {
-		match ctx.recv().await? {
-			FromOverseer::Signal(signal) => if handle_signal(&mut state, &mut ctx, signal).await? {
-				return Ok(());
-			},
-			FromOverseer::Communication { msg } => match msg {
-				PoVDistributionMessage::FetchPoV(relay_parent, descriptor, response_sender) =>
-					handle_fetch(
-						&mut state,
-						&mut ctx,
-						relay_parent,
-						descriptor,
-						response_sender,
-					).await?,
-				PoVDistributionMessage::DistributePoV(relay_parent, descriptor, pov) =>
-					handle_distribute(
-						&mut state,
-						&mut ctx,
-						relay_parent,
-						descriptor,
-						pov,
-					).await?,
-				PoVDistributionMessage::NetworkBridgeUpdateV1(event) =>
-					handle_network_update(
-						&mut state,
-						&mut ctx,
-						event,
-					).await?,
-			},
+	async fn run(
+		self,
+		mut ctx: impl SubsystemContext<Message = PoVDistributionMessage>,
+	) -> SubsystemResult<()> {
+		let mut state = State {
+			relay_parent_state: HashMap::new(),
+			peer_state: HashMap::new(),
+			our_view: View(Vec::new()),
+			metrics: self.metrics,
+		};
+
+		loop {
+			match ctx.recv().await? {
+				FromOverseer::Signal(signal) => if handle_signal(&mut state, &mut ctx, signal).await? {
+					return Ok(());
+				},
+				FromOverseer::Communication { msg } => match msg {
+					PoVDistributionMessage::FetchPoV(relay_parent, descriptor, response_sender) =>
+						handle_fetch(
+							&mut state,
+							&mut ctx,
+							relay_parent,
+							descriptor,
+							response_sender,
+						).await?,
+					PoVDistributionMessage::DistributePoV(relay_parent, descriptor, pov) =>
+						handle_distribute(
+							&mut state,
+							&mut ctx,
+							relay_parent,
+							descriptor,
+							pov,
+						).await?,
+					PoVDistributionMessage::NetworkBridgeUpdateV1(event) =>
+						handle_network_update(
+							&mut state,
+							&mut ctx,
+							event,
+						).await?,
+				},
+			}
 		}
 	}
 }
 
+
+
+#[derive(Clone)]
+struct MetricsInner {
+	povs_distributed: prometheus::Counter<prometheus::U64>,
+}
+
+/// Availability Distribution metrics.
+#[derive(Default, Clone)]
+pub struct Metrics(Option<MetricsInner>);
+
+impl Metrics {
+	fn on_pov_distributed(&self) {
+		if let Some(metrics) = &self.0 {
+			metrics.povs_distributed.inc();
+		}
+	}
+}
+
+impl metrics::Metrics for Metrics {
+	fn try_register(registry: &prometheus::Registry) -> std::result::Result<Self, prometheus::PrometheusError> {
+		let metrics = MetricsInner {
+			povs_distributed: prometheus::register(
+				prometheus::Counter::new(
+					"parachain_povs_distributed_total",
+					"Number of PoVs distributed to other peers."
+				)?,
+				registry,
+			)?,
+		};
+		Ok(Metrics(Some(metrics)))
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;
@@ -619,6 +676,7 @@ mod tests {
 				s
 			},
 			our_view: View(vec![hash_a, hash_b]),
+			metrics: Default::default(),
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
@@ -698,6 +756,7 @@ mod tests {
 				s
 			},
 			our_view: View(vec![hash_a]),
+			metrics: Default::default(),
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
@@ -775,6 +834,7 @@ mod tests {
 				s
 			},
 			our_view: View(vec![hash_a]),
+			metrics: Default::default(),
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
@@ -846,6 +906,7 @@ mod tests {
 				s
 			},
 			our_view: View(vec![hash_a]),
+			metrics: Default::default(),
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
@@ -934,6 +995,7 @@ mod tests {
 				s
 			},
 			our_view: View(vec![hash_a]),
+			metrics: Default::default(),
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
@@ -997,6 +1059,7 @@ mod tests {
 				s
 			},
 			our_view: View(vec![hash_a]),
+			metrics: Default::default(),
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
@@ -1058,6 +1121,7 @@ mod tests {
 				s
 			},
 			our_view: View(vec![hash_a]),
+			metrics: Default::default(),
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
@@ -1116,6 +1180,7 @@ mod tests {
 				s
 			},
 			our_view: View(vec![hash_a]),
+			metrics: Default::default(),
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
@@ -1201,6 +1266,7 @@ mod tests {
 				s
 			},
 			our_view: View(vec![hash_a, hash_b]),
+			metrics: Default::default(),
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
@@ -1263,6 +1329,7 @@ mod tests {
 				s
 			},
 			our_view: View(vec![hash_a]),
+			metrics: Default::default(),
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
@@ -1340,6 +1407,7 @@ mod tests {
 				s
 			},
 			our_view: View(vec![hash_a]),
+			metrics: Default::default(),
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
@@ -1422,6 +1490,7 @@ mod tests {
 				s
 			},
 			our_view: View(vec![hash_a]),
+			metrics: Default::default(),
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();

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

@@ -16,6 +16,7 @@ parity-scale-codec = "1.3.4"
 sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-staking = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem" }
+polkadot-node-subsystem-util = { path = "../../subsystem-util" }
 polkadot-node-network-protocol = { path = "../../network/protocol" }
 arrayvec = "0.5.1"
 indexmap = "1.4.0"

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

@@ -22,10 +22,13 @@
 use polkadot_subsystem::{
 	Subsystem, SubsystemResult, SubsystemContext, SpawnedSubsystem,
 	ActiveLeavesUpdate, FromOverseer, OverseerSignal,
+	messages::{
+		AllMessages, NetworkBridgeMessage, StatementDistributionMessage, CandidateBackingMessage,
+		RuntimeApiMessage, RuntimeApiRequest,
+	},
 };
-use polkadot_subsystem::messages::{
-	AllMessages, NetworkBridgeMessage, StatementDistributionMessage, CandidateBackingMessage,
-	RuntimeApiMessage, RuntimeApiRequest,
+use polkadot_node_subsystem_util::{
+	metrics::{self, prometheus},
 };
 use node_primitives::SignedFullStatement;
 use polkadot_primitives::v1::{
@@ -59,8 +62,13 @@ const BENEFIT_VALID_STATEMENT_FIRST: Rep = Rep::new(
 /// Typically we will only keep 1, but when a validator equivocates we will need to track 2.
 const VC_THRESHOLD: usize = 2;
 
+const LOG_TARGET: &str = "statement_distribution";
+
 /// The statement distribution subsystem.
-pub struct StatementDistribution;
+pub struct StatementDistribution {
+	// Prometheus metrics
+	metrics: Metrics,
+}
 
 impl<C> Subsystem<C> for StatementDistribution
 	where C: SubsystemContext<Message=StatementDistributionMessage>
@@ -70,7 +78,7 @@ impl<C> Subsystem<C> for StatementDistribution
 		// within `run`.
 		SpawnedSubsystem {
 			name: "statement-distribution-subsystem",
-			future: run(ctx).map(|_| ()).boxed(),
+			future: self.run(ctx).map(|_| ()).boxed(),
 		}
 	}
 }
@@ -111,14 +119,7 @@ fn note_hash(
 ) -> bool {
 	if observed.contains(&h) { return true; }
 
-	if observed.is_full() {
-		false
-	} else {
-		observed.try_push(h).expect("length of storage guarded above; \
-			only panics if length exceeds capacity; qed");
-
-		true
-	}
+	observed.try_push(h).is_ok()
 }
 
 /// knowledge that a peer has about goings-on in a relay parent.
@@ -502,6 +503,7 @@ async fn circulate_statement_and_dependents(
 	ctx: &mut impl SubsystemContext<Message = StatementDistributionMessage>,
 	relay_parent: Hash,
 	statement: SignedFullStatement,
+	metrics: &Metrics,
 ) -> SubsystemResult<()> {
 	if let Some(active_head)= active_heads.get_mut(&relay_parent) {
 
@@ -529,7 +531,8 @@ async fn circulate_statement_and_dependents(
 						ctx,
 						relay_parent,
 						candidate_hash,
-						&*active_head
+						&*active_head,
+						metrics,
 					).await?;
 				}
 			}
@@ -589,6 +592,7 @@ async fn send_statements_about(
 	relay_parent: Hash,
 	candidate_hash: Hash,
 	active_head: &ActiveHeadData,
+	metrics: &Metrics,
 ) -> SubsystemResult<()> {
 	for statement in active_head.statements_about(candidate_hash) {
 		if peer_data.send(&relay_parent, &statement.fingerprint()).is_some() {
@@ -600,6 +604,8 @@ async fn send_statements_about(
 			ctx.send_message(AllMessages::NetworkBridge(
 				NetworkBridgeMessage::SendValidationMessage(vec![peer.clone()], payload)
 			)).await?;
+
+			metrics.on_statement_distributed();
 		}
 	}
 
@@ -612,7 +618,8 @@ async fn send_statements(
 	peer_data: &mut PeerData,
 	ctx: &mut impl SubsystemContext<Message = StatementDistributionMessage>,
 	relay_parent: Hash,
-	active_head: &ActiveHeadData
+	active_head: &ActiveHeadData,
+	metrics: &Metrics,
 ) -> SubsystemResult<()> {
 	for statement in active_head.statements() {
 		if peer_data.send(&relay_parent, &statement.fingerprint()).is_some() {
@@ -624,6 +631,8 @@ async fn send_statements(
 			ctx.send_message(AllMessages::NetworkBridge(
 				NetworkBridgeMessage::SendValidationMessage(vec![peer.clone()], payload)
 			)).await?;
+
+			metrics.on_statement_distributed();
 		}
 	}
 
@@ -652,6 +661,7 @@ async fn handle_incoming_message<'a>(
 	active_heads: &'a mut HashMap<Hash, ActiveHeadData>,
 	ctx: &mut impl SubsystemContext<Message = StatementDistributionMessage>,
 	message: protocol_v1::StatementDistributionMessage,
+	metrics: &Metrics,
 ) -> SubsystemResult<Option<(Hash, &'a StoredStatement)>> {
 	let (relay_parent, statement) = match message {
 		protocol_v1::StatementDistributionMessage::Statement(r, s) => (r, s),
@@ -697,6 +707,7 @@ async fn handle_incoming_message<'a>(
 				relay_parent,
 				fingerprint.0.candidate_hash().clone(),
 				&*active_head,
+				metrics,
 			).await?
 		}
 		Ok(false) => {}
@@ -724,6 +735,7 @@ async fn update_peer_view_and_send_unlocked(
 	ctx: &mut impl SubsystemContext<Message = StatementDistributionMessage>,
 	active_heads: &HashMap<Hash, ActiveHeadData>,
 	new_view: View,
+	metrics: &Metrics,
 ) -> SubsystemResult<()> {
 	let old_view = std::mem::replace(&mut peer_data.view, new_view);
 
@@ -745,6 +757,7 @@ async fn update_peer_view_and_send_unlocked(
 				ctx,
 				new,
 				active_head,
+				metrics,
 			).await?;
 		}
 	}
@@ -758,6 +771,7 @@ async fn handle_network_update(
 	ctx: &mut impl SubsystemContext<Message = StatementDistributionMessage>,
 	our_view: &mut View,
 	update: NetworkBridgeEvent<protocol_v1::StatementDistributionMessage>,
+	metrics: &Metrics,
 ) -> SubsystemResult<()> {
 	match update {
 		NetworkBridgeEvent::PeerConnected(peer, _role) => {
@@ -782,6 +796,7 @@ async fn handle_network_update(
 						active_heads,
 						ctx,
 						message,
+						metrics,
 					).await?;
 
 					if let Some((relay_parent, new)) = new_stored {
@@ -808,6 +823,7 @@ async fn handle_network_update(
 						ctx,
 						&*active_heads,
 						view,
+						metrics,
 					).await
 				}
 				None => Ok(()),
@@ -819,7 +835,7 @@ async fn handle_network_update(
 
 			for new in our_view.difference(&old_view) {
 				if !active_heads.contains_key(&new) {
-					log::warn!(target: "statement_distribution", "Our network bridge view update \
+					log::warn!(target: LOG_TARGET, "Our network bridge view update \
 						inconsistent with `StartWork` messages we have received from overseer. \
 						Contains unknown hash {}", new);
 				}
@@ -831,94 +847,132 @@ async fn handle_network_update(
 
 }
 
-async fn run(
-	mut ctx: impl SubsystemContext<Message = StatementDistributionMessage>,
-) -> SubsystemResult<()> {
-	let mut peers: HashMap<PeerId, PeerData> = HashMap::new();
-	let mut our_view = View::default();
-	let mut active_heads: HashMap<Hash, ActiveHeadData> = HashMap::new();
-	let mut statement_listeners: Vec<mpsc::Sender<SignedFullStatement>> = Vec::new();
+impl StatementDistribution {
+	async fn run(
+		self,
+		mut ctx: impl SubsystemContext<Message = StatementDistributionMessage>,
+	) -> SubsystemResult<()> {
+		let mut peers: HashMap<PeerId, PeerData> = HashMap::new();
+		let mut our_view = View::default();
+		let mut active_heads: HashMap<Hash, ActiveHeadData> = HashMap::new();
+		let mut statement_listeners: Vec<mpsc::Sender<SignedFullStatement>> = Vec::new();
+		let metrics = self.metrics;
 
-	loop {
-		let message = ctx.recv().await?;
-		match message {
-			FromOverseer::Signal(OverseerSignal::ActiveLeaves(ActiveLeavesUpdate { activated, .. })) => {
-				for relay_parent in activated {
-					let (validators, session_index) = {
-						let (val_tx, val_rx) = oneshot::channel();
-						let (session_tx, session_rx) = oneshot::channel();
+		loop {
+			let message = ctx.recv().await?;
+			match message {
+				FromOverseer::Signal(OverseerSignal::ActiveLeaves(ActiveLeavesUpdate { activated, .. })) => {
+					for relay_parent in activated {
+						let (validators, session_index) = {
+							let (val_tx, val_rx) = oneshot::channel();
+							let (session_tx, session_rx) = oneshot::channel();
 
-						let val_message = AllMessages::RuntimeApi(
-							RuntimeApiMessage::Request(
-								relay_parent,
-								RuntimeApiRequest::Validators(val_tx),
-							),
-						);
-						let session_message = AllMessages::RuntimeApi(
-							RuntimeApiMessage::Request(
-								relay_parent,
-								RuntimeApiRequest::SessionIndexForChild(session_tx),
-							),
-						);
+							let val_message = AllMessages::RuntimeApi(
+								RuntimeApiMessage::Request(
+									relay_parent,
+									RuntimeApiRequest::Validators(val_tx),
+								),
+							);
+							let session_message = AllMessages::RuntimeApi(
+								RuntimeApiMessage::Request(
+									relay_parent,
+									RuntimeApiRequest::SessionIndexForChild(session_tx),
+								),
+							);
 
-						ctx.send_messages(
-							std::iter::once(val_message).chain(std::iter::once(session_message))
-						).await?;
+							ctx.send_messages(
+								std::iter::once(val_message).chain(std::iter::once(session_message))
+							).await?;
 
-						match (val_rx.await?, session_rx.await?) {
-							(Ok(v), Ok(s)) => (v, s),
-							(Err(e), _) | (_, Err(e)) => {
-								log::warn!(
-									target: "statement_distribution",
-									"Failed to fetch runtime API data for active leaf: {:?}",
-									e,
-								);
+							match (val_rx.await?, session_rx.await?) {
+								(Ok(v), Ok(s)) => (v, s),
+								(Err(e), _) | (_, Err(e)) => {
+									log::warn!(
+										target: LOG_TARGET,
+										"Failed to fetch runtime API data for active leaf: {:?}",
+										e,
+									);
 
-								// Lacking this bookkeeping might make us behave funny, although
-								// not in any slashable way. But we shouldn't take down the node
-								// on what are likely spurious runtime API errors.
-								continue;
+									// Lacking this bookkeeping might make us behave funny, although
+									// not in any slashable way. But we shouldn't take down the node
+									// on what are likely spurious runtime API errors.
+									continue;
+								}
 							}
-						}
-					};
+						};
 
-					active_heads.entry(relay_parent)
-						.or_insert(ActiveHeadData::new(validators, session_index));
+						active_heads.entry(relay_parent)
+							.or_insert(ActiveHeadData::new(validators, session_index));
+					}
 				}
-			}
-			FromOverseer::Signal(OverseerSignal::BlockFinalized(_block_hash)) => {
-				// do nothing
-			}
-			FromOverseer::Signal(OverseerSignal::Conclude) => break,
-			FromOverseer::Communication { msg } => match msg {
-				StatementDistributionMessage::Share(relay_parent, statement) => {
-					inform_statement_listeners(
-						&statement,
-						&mut statement_listeners,
-					).await;
-					circulate_statement_and_dependents(
-						&mut peers,
-						&mut active_heads,
-						&mut ctx,
-						relay_parent,
-						statement,
-					).await?;
+				FromOverseer::Signal(OverseerSignal::BlockFinalized(_block_hash)) => {
+					// do nothing
 				}
-				StatementDistributionMessage::NetworkBridgeUpdateV1(event) =>
-					handle_network_update(
-						&mut peers,
-						&mut active_heads,
-						&mut ctx,
-						&mut our_view,
-						event,
-					).await?,
-				StatementDistributionMessage::RegisterStatementListener(tx) => {
-					statement_listeners.push(tx);
+				FromOverseer::Signal(OverseerSignal::Conclude) => break,
+				FromOverseer::Communication { msg } => match msg {
+					StatementDistributionMessage::Share(relay_parent, statement) => {
+						inform_statement_listeners(
+							&statement,
+							&mut statement_listeners,
+						).await;
+						circulate_statement_and_dependents(
+							&mut peers,
+							&mut active_heads,
+							&mut ctx,
+							relay_parent,
+							statement,
+							&metrics,
+						).await?;
+					}
+					StatementDistributionMessage::NetworkBridgeUpdateV1(event) =>
+						handle_network_update(
+							&mut peers,
+							&mut active_heads,
+							&mut ctx,
+							&mut our_view,
+							event,
+							&metrics,
+						).await?,
+					StatementDistributionMessage::RegisterStatementListener(tx) => {
+						statement_listeners.push(tx);
+					}
 				}
 			}
 		}
+		Ok(())
+	}
+}
+
+#[derive(Clone)]
+struct MetricsInner {
+	statements_distributed: prometheus::Counter<prometheus::U64>,
+}
+
+/// Statement Distribution metrics.
+#[derive(Default, Clone)]
+pub struct Metrics(Option<MetricsInner>);
+
+impl Metrics {
+	fn on_statement_distributed(&self) {
+		if let Some(metrics) = &self.0 {
+			metrics.statements_distributed.inc();
+		}
+	}
+}
+
+impl metrics::Metrics for Metrics {
+	fn try_register(registry: &prometheus::Registry) -> std::result::Result<Self, prometheus::PrometheusError> {
+		let metrics = MetricsInner {
+			statements_distributed: prometheus::register(
+				prometheus::Counter::new(
+					"parachain_statements_distributed_total",
+					"Number of candidate validity statements distributed to other peers."
+				)?,
+				registry,
+			)?,
+		};
+		Ok(Metrics(Some(metrics)))
 	}
-	Ok(())
 }
 
 #[cfg(test)]
@@ -1256,6 +1310,7 @@ mod tests {
 				&mut ctx,
 				&active_heads,
 				new_view.clone(),
+				&Default::default(),
 			).await.unwrap();
 
 			assert_eq!(peer_data.view, new_view);

polkadot/node/overseer/src/lib.rs

@@ -470,6 +470,7 @@ pub struct AllSubsystems<CV, CB, CS, SD, AD, BS, BD, P, PoVD, RA, AS, NB, CA, CG
 struct MetricsInner {
 	activated_heads_total: prometheus::Counter<prometheus::U64>,
 	deactivated_heads_total: prometheus::Counter<prometheus::U64>,
+	messages_relayed_total: prometheus::Counter<prometheus::U64>,
 }
 
 #[derive(Default, Clone)]
@@ -487,6 +488,12 @@ impl Metrics {
 			metrics.deactivated_heads_total.inc();
 		}
 	}
+
+	fn on_message_relayed(&self) {
+		if let Some(metrics) = &self.0 {
+			metrics.messages_relayed_total.inc();
+		}
+	}
 }
 
 impl metrics::Metrics for Metrics {
@@ -506,6 +513,13 @@ impl metrics::Metrics for Metrics {
 				)?,
 				registry,
 			)?,
+			messages_relayed_total: prometheus::register(
+				prometheus::Counter::new(
+					"parachain_messages_relayed_total",
+					"Number of messages relayed by Overseer."
+				)?,
+				registry,
+			)?,
 		};
 		Ok(Metrics(Some(metrics)))
 	}
@@ -1046,10 +1060,11 @@ where
 	}
 
 	async fn route_message(&mut self, msg: AllMessages) {
+		self.metrics.on_message_relayed();
 		match msg {
 			AllMessages::CandidateValidation(msg) => {
 				if let Some(ref mut s) = self.candidate_validation_subsystem.instance {
-					let _= s.tx.send(FromOverseer::Communication { msg }).await;
+					let _ = s.tx.send(FromOverseer::Communication { msg }).await;
 				}
 			}
 			AllMessages::CandidateBacking(msg) => {
@@ -1209,6 +1224,7 @@ fn spawn<S: SpawnNamed, M: Send + 'static>(
 #[cfg(test)]
 mod tests {
 	use std::sync::atomic;
+	use std::collections::HashMap;
 	use futures::{executor, pin_mut, select, channel::mpsc, FutureExt};
 
 	use polkadot_primitives::v1::{BlockData, CollatorPair, PoV};
@@ -1435,27 +1451,35 @@ mod tests {
 
 			handler.block_imported(second_block).await.unwrap();
 			handler.block_imported(third_block).await.unwrap();
+			handler.send_msg(AllMessages::CandidateValidation(test_candidate_validation_msg())).await.unwrap();
 			handler.stop().await.unwrap();
 
 			select! {
 				res = overseer_fut => {
 					assert!(res.is_ok());
-					let (activated, deactivated) = extract_metrics(&registry);
-					assert_eq!(activated, 3);
-					assert_eq!(deactivated, 2);
+					let metrics = extract_metrics(&registry);
+					assert_eq!(metrics["activated"], 3);
+					assert_eq!(metrics["deactivated"], 2);
+					assert_eq!(metrics["relayed"], 1);
 				},
 				complete => (),
 			}
 		});
 	}
 
-	fn extract_metrics(registry: &prometheus::Registry) -> (u64, u64) {
+	fn extract_metrics(registry: &prometheus::Registry) -> HashMap<&'static str, u64> {
 		let gather = registry.gather();
 		assert_eq!(gather[0].get_name(), "parachain_activated_heads_total");
 		assert_eq!(gather[1].get_name(), "parachain_deactivated_heads_total");
+		assert_eq!(gather[2].get_name(), "parachain_messages_relayed_total");
 		let activated = gather[0].get_metric()[0].get_counter().get_value() as u64;
 		let deactivated = gather[1].get_metric()[0].get_counter().get_value() as u64;
-		(activated, deactivated)
+		let relayed = gather[2].get_metric()[0].get_counter().get_value() as u64;
+		let mut result = HashMap::new();
+		result.insert("activated", activated);
+		result.insert("deactivated", deactivated);
+		result.insert("relayed", relayed);
+		result
 	}
 
 	// Spawn a subsystem that immediately exits.