Infrastructure improvements (#2897)

* Factor out runtime module into utils.

* Add maybe_authority information to `PeerConnected` event.

We already gather this information in authority discovery, so we might
as well share it with others.

This opens up an easy path to trigger validators differently from normal
nodes, e.g. for prioritization. This change has become more important
now, that we just connect to all validators and therefore just have a
long peer list without any information about those nodes.

* Test fix.

polkadot/Cargo.lock

@@ -6096,6 +6096,7 @@ dependencies = [
  "futures 0.3.13",
  "futures-timer 3.0.2",
  "log",
+ "lru",
  "metered-channel",
  "parity-scale-codec",
  "parking_lot 0.11.1",

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

@@ -592,7 +592,7 @@ impl metrics::Metrics for Metrics {
 
 #[cfg(test)]
 mod tests {
-    use super::*;
+	use super::*;
 	use polkadot_node_subsystem_test_helpers as test_helpers;
 	use polkadot_primitives::v1::{HeadData, UpwardMessage};
 	use sp_core::testing::TaskExecutor;

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

@@ -191,7 +191,7 @@ impl State {
 		event: NetworkBridgeEvent<protocol_v1::ApprovalDistributionMessage>,
 	) {
 		match event {
-			NetworkBridgeEvent::PeerConnected(peer_id, role) => {
+			NetworkBridgeEvent::PeerConnected(peer_id, role, _) => {
 				// insert a blank view if none already present
 				tracing::trace!(
 					target: LOG_TARGET,

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

@@ -117,7 +117,7 @@ async fn setup_peer_with_view(
 	overseer_send(
 		virtual_overseer,
 		ApprovalDistributionMessage::NetworkBridgeUpdateV1(
-			NetworkBridgeEvent::PeerConnected(peer_id.clone(), ObservedRole::Full)
+			NetworkBridgeEvent::PeerConnected(peer_id.clone(), ObservedRole::Full, None)
 		)
 	).await;
 	overseer_send(

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

@@ -18,12 +18,15 @@
 //! Error handling related code and Error/Result definitions.
 
 use polkadot_node_network_protocol::request_response::request::RequestError;
+use polkadot_primitives::v1::SessionIndex;
 use thiserror::Error;
 
 use futures::channel::oneshot;
 
-use polkadot_node_subsystem_util::Error as UtilError;
-use polkadot_primitives::v1::SessionIndex;
+use polkadot_node_subsystem_util::{
+	runtime,
+	Error as UtilError,
+};
 use polkadot_subsystem::{errors::RuntimeApiError, SubsystemError};
 
 use crate::LOG_TARGET;
@@ -74,10 +77,6 @@ pub enum Error {
 	#[error("Runtime API error")]
 	RuntimeRequest(RuntimeApiError),
 
-	/// We tried fetching a session info which was not available.
-	#[error("There was no session with the given index")]
-	NoSuchSession(SessionIndex),
-
 	/// Fetching PoV failed with `RequestError`.
 	#[error("FetchPoV request error")]
 	FetchPoV(#[source] RequestError),
@@ -92,10 +91,24 @@ pub enum Error {
 	/// No validator with the index could be found in current session.
 	#[error("Given validator index could not be found")]
 	InvalidValidatorIndex,
+
+	/// We tried fetching a session info which was not available.
+	#[error("There was no session with the given index")]
+	NoSuchSession(SessionIndex),
+
+	/// Errors coming from runtime::Runtime.
+	#[error("Error while accessing runtime information")]
+	Runtime(#[source] runtime::Error),
 }
 
 pub type Result<T> = std::result::Result<T, Error>;
 
+impl From<runtime::Error> for Error {
+	fn from(err: runtime::Error) -> Self {
+		Self::Runtime(err)
+	}
+}
+
 impl From<SubsystemError> for Error {
 	fn from(err: SubsystemError) -> Self {
 		Self::IncomingMessageChannel(err)

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

@@ -28,9 +28,7 @@ mod error;
 pub use error::Error;
 use error::{Result, log_error};
 
-/// Runtime requests.
-mod runtime;
-use runtime::Runtime;
+use polkadot_node_subsystem_util::runtime::Runtime;
 
 /// `Requester` taking care of requesting chunks for candidates pending availability.
 mod requester;

polkadot/node/network/availability-distribution/src/pov_requester/mod.rs

@@ -33,8 +33,9 @@ use polkadot_subsystem::{
 	ActiveLeavesUpdate, SubsystemContext, ActivatedLeaf,
 	messages::{AllMessages, NetworkBridgeMessage, IfDisconnected}
 };
+use polkadot_node_subsystem_util::runtime::{Runtime, ValidatorInfo};
 
-use crate::{error::{Error, log_error}, runtime::{Runtime, ValidatorInfo}};
+use crate::error::{Error, log_error};
 
 /// Number of sessions we want to keep in the LRU.
 const NUM_SESSIONS: usize = 2;
@@ -274,7 +275,7 @@ mod tests {
 		let (mut context, mut virtual_overseer) =
 			test_helpers::make_subsystem_context::<AvailabilityDistributionMessage, TaskExecutor>(pool.clone());
 		let keystore = make_ferdie_keystore();
-		let mut runtime = crate::runtime::Runtime::new(keystore);
+		let mut runtime = polkadot_node_subsystem_util::runtime::Runtime::new(keystore);
 
 		let (tx, rx) = oneshot::channel();
 		let testee = async {

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

@@ -508,7 +508,7 @@ where
 	let _timer = metrics.time_handle_network_msg();
 
 	match bridge_message {
-		NetworkBridgeEvent::PeerConnected(peerid, role) => {
+		NetworkBridgeEvent::PeerConnected(peerid, role, _) => {
 			tracing::trace!(
 				target: LOG_TARGET,
 				?peerid,
@@ -1335,7 +1335,7 @@ mod test {
 				&mut ctx,
 				&mut state,
 				&Default::default(),
-				NetworkBridgeEvent::PeerConnected(peer_b.clone(), ObservedRole::Full),
+				NetworkBridgeEvent::PeerConnected(peer_b.clone(), ObservedRole::Full, None),
 			));
 
 			// make peer b interested

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

@@ -36,7 +36,7 @@ use polkadot_subsystem::messages::{
 	NetworkBridgeMessage, AllMessages,
 	CollatorProtocolMessage, NetworkBridgeEvent,
 };
-use polkadot_primitives::v1::{Hash, BlockNumber};
+use polkadot_primitives::v1::{Hash, BlockNumber, AuthorityDiscoveryId};
 use polkadot_node_network_protocol::{
 	PeerId, peer_set::PeerSet, View, v1 as protocol_v1, OurView, UnifiedReputationChange as Rep,
 	ObservedRole,
@@ -316,7 +316,7 @@ impl From<SubsystemError> for UnexpectedAbort {
 
 // notifications to be passed through to the validator discovery worker.
 enum ValidatorDiscoveryNotification {
-	PeerConnected(PeerId, PeerSet),
+	PeerConnected(PeerId, PeerSet, Option<AuthorityDiscoveryId>),
 	PeerDisconnected(PeerId, PeerSet),
 }
 
@@ -540,11 +540,11 @@ where
 			},
 			notification = validator_discovery_notifications.next().fuse() => match notification {
 				None => return Ok(()),
-				Some(ValidatorDiscoveryNotification::PeerConnected(peer, peer_set)) => {
+				Some(ValidatorDiscoveryNotification::PeerConnected(peer, peer_set, maybe_auth)) => {
 					validator_discovery.on_peer_connected(
 						peer.clone(),
 						peer_set,
-						&mut authority_discovery_service,
+						maybe_auth,
 					).await;
 				}
 				Some(ValidatorDiscoveryNotification::PeerDisconnected(peer, peer_set)) => {
@@ -555,9 +555,10 @@ where
 	}
 }
 
-async fn handle_network_messages(
+async fn handle_network_messages<AD: validator_discovery::AuthorityDiscovery>(
 	mut sender: impl SubsystemSender,
 	mut network_service: impl Network,
+	mut authority_discovery_service: AD,
 	mut request_multiplexer: RequestMultiplexer,
 	mut validator_discovery_notifications: mpsc::Sender<ValidatorDiscoveryNotification>,
 	metrics: Metrics,
@@ -607,10 +608,14 @@ async fn handle_network_messages(
 						shared.local_view.clone().unwrap_or(View::default())
 					};
 
+					let maybe_authority =
+						authority_discovery_service
+							.get_authority_id_by_peer_id(peer).await;
+
 					// Failure here means that the other side of the network bridge
 					// has concluded and this future will be dropped in due course.
 					let _ = validator_discovery_notifications.send(
-						ValidatorDiscoveryNotification::PeerConnected(peer.clone(), peer_set)
+						ValidatorDiscoveryNotification::PeerConnected(peer, peer_set, maybe_authority.clone())
 					).await;
 
 
@@ -618,7 +623,7 @@ async fn handle_network_messages(
 						PeerSet::Validation => {
 							dispatch_validation_events_to_all(
 								vec![
-									NetworkBridgeEvent::PeerConnected(peer.clone(), role),
+									NetworkBridgeEvent::PeerConnected(peer.clone(), role, maybe_authority),
 									NetworkBridgeEvent::PeerViewChange(
 										peer.clone(),
 										View::default(),
@@ -640,7 +645,7 @@ async fn handle_network_messages(
 						PeerSet::Collation => {
 							dispatch_collation_events_to_all(
 								vec![
-									NetworkBridgeEvent::PeerConnected(peer.clone(), role),
+									NetworkBridgeEvent::PeerConnected(peer.clone(), role, maybe_authority),
 									NetworkBridgeEvent::PeerViewChange(
 										peer.clone(),
 										View::default(),
@@ -858,6 +863,7 @@ where
 	let (remote, network_event_handler) = handle_network_messages(
 		ctx.sender().clone(),
 		network_service.clone(),
+		authority_discovery_service.clone(),
 		request_multiplexer,
 		validation_worker_tx,
 		metrics.clone(),
@@ -1191,6 +1197,7 @@ mod tests {
 		_req_configs: Vec<RequestResponseConfig>,
 	}
 
+	#[derive(Clone)]
 	struct TestAuthorityDiscovery;
 
 	// The test's view of the network. This receives updates from the subsystem in the form
@@ -1796,7 +1803,7 @@ mod tests {
 			// bridge will inform about all connected peers.
 			{
 				assert_sends_validation_event_to_all(
-					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full),
+					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full, None),
 					&mut virtual_overseer,
 				).await;
 
@@ -1848,7 +1855,7 @@ mod tests {
 			// bridge will inform about all connected peers.
 			{
 				assert_sends_validation_event_to_all(
-					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full),
+					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full, None),
 					&mut virtual_overseer,
 				).await;
 
@@ -1920,7 +1927,7 @@ mod tests {
 			// bridge will inform about all connected peers.
 			{
 				assert_sends_validation_event_to_all(
-					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full),
+					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full, None),
 					&mut virtual_overseer,
 				).await;
 
@@ -1932,7 +1939,7 @@ mod tests {
 
 			{
 				assert_sends_collation_event_to_all(
-					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full),
+					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full, None),
 					&mut virtual_overseer,
 				).await;
 
@@ -2004,7 +2011,7 @@ mod tests {
 			// bridge will inform about all connected peers.
 			{
 				assert_sends_validation_event_to_all(
-					NetworkBridgeEvent::PeerConnected(peer_a.clone(), ObservedRole::Full),
+					NetworkBridgeEvent::PeerConnected(peer_a.clone(), ObservedRole::Full, None),
 					&mut virtual_overseer,
 				).await;
 
@@ -2016,7 +2023,7 @@ mod tests {
 
 			{
 				assert_sends_collation_event_to_all(
-					NetworkBridgeEvent::PeerConnected(peer_b.clone(), ObservedRole::Full),
+					NetworkBridgeEvent::PeerConnected(peer_b.clone(), ObservedRole::Full, None),
 					&mut virtual_overseer,
 				).await;
 
@@ -2099,7 +2106,7 @@ mod tests {
 			// bridge will inform about all connected peers.
 			{
 				assert_sends_validation_event_to_all(
-					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full),
+					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full, None),
 					&mut virtual_overseer,
 				).await;
 
@@ -2111,7 +2118,7 @@ mod tests {
 
 			{
 				assert_sends_collation_event_to_all(
-					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full),
+					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full, None),
 					&mut virtual_overseer,
 				).await;
 
@@ -2259,7 +2266,7 @@ mod tests {
 			// bridge will inform about all connected peers.
 			{
 				assert_sends_validation_event_to_all(
-					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full),
+					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full, None),
 					&mut virtual_overseer,
 				).await;
 
@@ -2271,7 +2278,7 @@ mod tests {
 
 			{
 				assert_sends_collation_event_to_all(
-					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full),
+					NetworkBridgeEvent::PeerConnected(peer.clone(), ObservedRole::Full, None),
 					&mut virtual_overseer,
 				).await;
 

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

@@ -34,7 +34,7 @@ const LOG_TARGET: &str = "parachain::validator-discovery";
 
 /// An abstraction over the authority discovery service.
 #[async_trait]
-pub trait AuthorityDiscovery: Send + 'static {
+pub trait AuthorityDiscovery: Send + Clone + 'static {
 	/// Get the addresses for the given [`AuthorityId`] from the local address cache.
 	async fn get_addresses_by_authority_id(&mut self, authority: AuthorityDiscoveryId) -> Option<Vec<Multiaddr>>;
 	/// Get the [`AuthorityId`] for the given [`PeerId`] from the local address cache.
@@ -307,16 +307,15 @@ impl<N: Network, AD: AuthorityDiscovery> Service<N, AD> {
 	}
 
 	/// Should be called when a peer connected.
-	#[tracing::instrument(level = "trace", skip(self, authority_discovery_service), fields(subsystem = LOG_TARGET))]
+	#[tracing::instrument(level = "trace", skip(self), fields(subsystem = LOG_TARGET))]
 	pub async fn on_peer_connected(
 		&mut self,
 		peer_id: PeerId,
 		peer_set: PeerSet,
-		authority_discovery_service: &mut AD,
+		maybe_authority: Option<AuthorityDiscoveryId>,
 	) {
 		let state = &mut self.state[peer_set];
 		// check if it's an authority we've been waiting for
-		let maybe_authority = authority_discovery_service.get_authority_id_by_peer_id(peer_id.clone()).await;
 		if let Some(authority) = maybe_authority {
 			for request in state.non_revoked_discovery_requests.iter_mut() {
 				let _ = request.on_authority_connected(&authority, &peer_id);
@@ -359,7 +358,7 @@ mod tests {
 		peers_set: HashSet<Multiaddr>,
 	}
 
-	#[derive(Default)]
+	#[derive(Default, Clone)]
 	struct TestAuthorityDiscovery {
 		by_authority_id: HashMap<AuthorityDiscoveryId, Multiaddr>,
 		by_peer_id: HashMap<PeerId, AuthorityDiscoveryId>,
@@ -469,7 +468,8 @@ mod tests {
 			let req1 = vec![authority_ids[0].clone(), authority_ids[1].clone()];
 			let (sender, mut receiver) = mpsc::channel(2);
 
-			service.on_peer_connected(peer_ids[0].clone(), PeerSet::Validation, &mut ads).await;
+			let maybe_authority = ads.get_authority_id_by_peer_id(peer_ids[0]).await;
+			service.on_peer_connected(peer_ids[0].clone(), PeerSet::Validation, maybe_authority).await;
 
 			let _ = service.on_request(
 				req1,
@@ -509,12 +509,14 @@ mod tests {
 			).await;
 
 
-			service.on_peer_connected(peer_ids[0].clone(), PeerSet::Validation, &mut ads).await;
+			let maybe_authority = ads.get_authority_id_by_peer_id(peer_ids[0]).await;
+			service.on_peer_connected(peer_ids[0].clone(), PeerSet::Validation, maybe_authority).await;
 			let reply1 = receiver.next().await.unwrap();
 			assert_eq!(reply1.0, authority_ids[0]);
 			assert_eq!(reply1.1, peer_ids[0]);
 
-			service.on_peer_connected(peer_ids[1].clone(), PeerSet::Validation, &mut ads).await;
+			let maybe_authority = ads.get_authority_id_by_peer_id(peer_ids[1]).await;
+			service.on_peer_connected(peer_ids[1].clone(), PeerSet::Validation, maybe_authority).await;
 			let reply2 = receiver.next().await.unwrap();
 			assert_eq!(reply2.0, authority_ids[1]);
 			assert_eq!(reply2.1, peer_ids[1]);
@@ -534,8 +536,10 @@ mod tests {
 		futures::executor::block_on(async move {
 			let (sender, mut receiver) = mpsc::channel(1);
 
-			service.on_peer_connected(peer_ids[0].clone(), PeerSet::Validation, &mut ads).await;
-			service.on_peer_connected(peer_ids[1].clone(), PeerSet::Validation, &mut ads).await;
+			let maybe_authority = ads.get_authority_id_by_peer_id(peer_ids[0]).await;
+			service.on_peer_connected(peer_ids[0].clone(), PeerSet::Validation, maybe_authority).await;
+			let maybe_authority = ads.get_authority_id_by_peer_id(peer_ids[1]).await;
+			service.on_peer_connected(peer_ids[1].clone(), PeerSet::Validation, maybe_authority).await;
 
 			let (ns, ads) = service.on_request(
 				vec![authority_ids[0].clone()],
@@ -580,8 +584,10 @@ mod tests {
 		futures::executor::block_on(async move {
 			let (sender, mut receiver) = mpsc::channel(1);
 
-			service.on_peer_connected(peer_ids[0].clone(), PeerSet::Validation, &mut ads).await;
-			service.on_peer_connected(peer_ids[1].clone(), PeerSet::Validation, &mut ads).await;
+			let maybe_authority = ads.get_authority_id_by_peer_id(peer_ids[0]).await;
+			service.on_peer_connected(peer_ids[0].clone(), PeerSet::Validation, maybe_authority).await;
+			let maybe_authority = ads.get_authority_id_by_peer_id(peer_ids[1]).await;
+			service.on_peer_connected(peer_ids[1].clone(), PeerSet::Validation, maybe_authority).await;
 
 			let (ns, ads) = service.on_request(
 				vec![authority_ids[0].clone(), authority_ids[2].clone()],
@@ -645,7 +651,8 @@ mod tests {
 		futures::executor::block_on(async move {
 			let (sender, mut receiver) = mpsc::channel(1);
 
-			service.on_peer_connected(validator_peer_id.clone(), PeerSet::Validation, &mut ads).await;
+			let maybe_authority = ads.get_authority_id_by_peer_id(validator_peer_id).await;
+			service.on_peer_connected(validator_peer_id.clone(), PeerSet::Validation, maybe_authority).await;
 
 			let address = known_multiaddr()[0].clone().with(Protocol::P2p(validator_peer_id.clone().into()));
 			ads.by_peer_id.insert(validator_peer_id.clone(), validator_id.clone());

polkadot/node/network/collator-protocol/src/collator_side.rs

@@ -791,7 +791,7 @@ async fn handle_network_msg(
 	use NetworkBridgeEvent::*;
 
 	match bridge_message {
-		PeerConnected(peer_id, observed_role) => {
+		PeerConnected(peer_id, observed_role, _) => {
 			// If it is possible that a disconnected validator would attempt a reconnect
 			// it should be handled here.
 			tracing::trace!(
@@ -1343,6 +1343,7 @@ mod tests {
 				NetworkBridgeEvent::PeerConnected(
 					peer.clone(),
 					polkadot_node_network_protocol::ObservedRole::Authority,
+					None,
 				),
 			),
 		).await;

polkadot/node/network/collator-protocol/src/validator_side.rs

@@ -873,7 +873,7 @@ where
 	use NetworkBridgeEvent::*;
 
 	match bridge_message {
-		PeerConnected(peer_id, _role) => {
+		PeerConnected(peer_id, _role, _) => {
 			state.peer_data.entry(peer_id).or_default();
 			state.metrics.note_collator_peer_count(state.peer_data.len());
 		},
@@ -1469,6 +1469,7 @@ mod tests {
 					NetworkBridgeEvent::PeerConnected(
 						peer_b,
 						ObservedRole::Full,
+						None,
 					),
 				)
 			).await;
@@ -1543,6 +1544,7 @@ mod tests {
 					NetworkBridgeEvent::PeerConnected(
 						peer_b,
 						ObservedRole::Full,
+						None,
 					),
 				)
 			).await;
@@ -1553,6 +1555,7 @@ mod tests {
 					NetworkBridgeEvent::PeerConnected(
 						peer_c,
 						ObservedRole::Full,
+						None,
 					),
 				)
 			).await;
@@ -1636,6 +1639,7 @@ mod tests {
 					NetworkBridgeEvent::PeerConnected(
 						peer_b,
 						ObservedRole::Full,
+						None,
 					),
 				)
 			).await;
@@ -1704,6 +1708,7 @@ mod tests {
 					NetworkBridgeEvent::PeerConnected(
 						peer_b,
 						ObservedRole::Full,
+						None,
 					),
 				)
 			).await;
@@ -1714,6 +1719,7 @@ mod tests {
 					NetworkBridgeEvent::PeerConnected(
 						peer_c,
 						ObservedRole::Full,
+						None,
 					),
 				)
 			).await;
@@ -1918,6 +1924,7 @@ mod tests {
 					NetworkBridgeEvent::PeerConnected(
 						peer_b.clone(),
 						ObservedRole::Full,
+						None,
 					)
 				)
 			).await;
@@ -2012,6 +2019,7 @@ mod tests {
 					NetworkBridgeEvent::PeerConnected(
 						peer_b.clone(),
 						ObservedRole::Full,
+						None,
 					)
 				)
 			).await;
@@ -2153,6 +2161,7 @@ mod tests {
 					NetworkBridgeEvent::PeerConnected(
 						peer_b.clone(),
 						ObservedRole::Full,
+						None,
 					)
 				)
 			).await;
@@ -2199,6 +2208,7 @@ mod tests {
 					NetworkBridgeEvent::PeerConnected(
 						peer_b.clone(),
 						ObservedRole::Full,
+						None,
 					)
 				)
 			).await;
@@ -2270,6 +2280,7 @@ mod tests {
 					NetworkBridgeEvent::PeerConnected(
 						peer_b.clone(),
 						ObservedRole::Full,
+						None,
 					)
 				)
 			).await;

polkadot/node/network/protocol/src/request_response/mod.rs

@@ -154,7 +154,7 @@ impl Protocol {
 				name: p_name,
 				max_request_size: 1_000,
 				// Available data size is dominated code size.
-                // + 1000 to account for protocol overhead (should be way less).
+				// + 1000 to account for protocol overhead (should be way less).
 				max_response_size: MAX_CODE_SIZE as u64 + 1000,
 				// We need statement fetching to be fast and will try our best at the responding
 				// side to answer requests within that timeout, assuming a bandwidth of 500Mbit/s
@@ -199,7 +199,7 @@ impl Protocol {
 				// waisting precious time.
 				let available_bandwidth = 7 * MIN_BANDWIDTH_BYTES / 10;
 				let size = u64::saturating_sub(
-                    STATEMENTS_TIMEOUT.as_millis() as u64 * available_bandwidth / (1000 * MAX_CODE_SIZE as u64),
+					STATEMENTS_TIMEOUT.as_millis() as u64 * available_bandwidth / (1000 * MAX_CODE_SIZE as u64),
 					MAX_PARALLEL_STATEMENT_REQUESTS as u64
 				);
 				debug_assert!(

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

@@ -1437,7 +1437,7 @@ async fn handle_network_update(
 	metrics: &Metrics,
 ) {
 	match update {
-		NetworkBridgeEvent::PeerConnected(peer, role) => {
+		NetworkBridgeEvent::PeerConnected(peer, role, _) => {
 			tracing::trace!(
 				target: LOG_TARGET,
 				?peer,
@@ -2667,13 +2667,13 @@ mod tests {
 			// notify of peers and view
 			handle.send(FromOverseer::Communication {
 				msg: StatementDistributionMessage::NetworkBridgeUpdateV1(
-					NetworkBridgeEvent::PeerConnected(peer_a.clone(), ObservedRole::Full)
+					NetworkBridgeEvent::PeerConnected(peer_a.clone(), ObservedRole::Full, None)
 				)
 			}).await;
 
 			handle.send(FromOverseer::Communication {
 				msg: StatementDistributionMessage::NetworkBridgeUpdateV1(
-					NetworkBridgeEvent::PeerConnected(peer_b.clone(), ObservedRole::Full)
+					NetworkBridgeEvent::PeerConnected(peer_b.clone(), ObservedRole::Full, None)
 				)
 			}).await;
 
@@ -2835,23 +2835,23 @@ mod tests {
 			// notify of peers and view
 			handle.send(FromOverseer::Communication {
 				msg: StatementDistributionMessage::NetworkBridgeUpdateV1(
-					NetworkBridgeEvent::PeerConnected(peer_a.clone(), ObservedRole::Full)
+					NetworkBridgeEvent::PeerConnected(peer_a.clone(), ObservedRole::Full, None)
 				)
 			}).await;
 
 			handle.send(FromOverseer::Communication {
 				msg: StatementDistributionMessage::NetworkBridgeUpdateV1(
-					NetworkBridgeEvent::PeerConnected(peer_b.clone(), ObservedRole::Full)
+					NetworkBridgeEvent::PeerConnected(peer_b.clone(), ObservedRole::Full, None)
 				)
 			}).await;
 			handle.send(FromOverseer::Communication {
 				msg: StatementDistributionMessage::NetworkBridgeUpdateV1(
-					NetworkBridgeEvent::PeerConnected(peer_c.clone(), ObservedRole::Full)
+					NetworkBridgeEvent::PeerConnected(peer_c.clone(), ObservedRole::Full, None)
 				)
 			}).await;
 			handle.send(FromOverseer::Communication {
 				msg: StatementDistributionMessage::NetworkBridgeUpdateV1(
-					NetworkBridgeEvent::PeerConnected(peer_bad.clone(), ObservedRole::Full)
+					NetworkBridgeEvent::PeerConnected(peer_bad.clone(), ObservedRole::Full, None)
 				)
 			}).await;
 

polkadot/node/subsystem-util/Cargo.toml

@@ -16,6 +16,7 @@ rand = "0.8.3"
 streamunordered = "0.5.1"
 thiserror = "1.0.23"
 tracing = "0.1.25"
+lru = "0.6.5"
 
 polkadot-node-primitives = { path = "../primitives" }
 polkadot-node-subsystem = { path = "../subsystem" }

polkadot/node/subsystem-util/src/lib.rs

@@ -65,6 +65,9 @@ pub mod reexports {
 	};
 }
 
+/// Convenient and efficient runtime info access.
+pub mod runtime;
+
 /// Duration a job will wait after sending a stop signal before hard-aborting.
 pub const JOB_GRACEFUL_STOP_DURATION: Duration = Duration::from_secs(1);
 /// Capacity of channels to and from individual jobs

polkadot/node/subsystem-util/src/runtime/error.rs

@@ -0,0 +1,52 @@
+// Copyright 2021 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+//! Error handling related code and Error/Result definitions.
+
+use thiserror::Error;
+use futures::channel::oneshot;
+
+use polkadot_node_subsystem::errors::RuntimeApiError;
+use polkadot_primitives::v1::SessionIndex;
+
+pub type Result<T> = std::result::Result<T, Error>;
+
+/// Errors for fetching of runtime information.
+#[derive(Debug, Error)]
+pub enum Error {
+	/// Runtime API subsystem is down, which means we're shutting down.
+	#[error("Runtime request canceled")]
+	RuntimeRequestCanceled(oneshot::Canceled),
+
+	/// Some request to the runtime failed.
+	/// For example if we prune a block we're requesting info about.
+	#[error("Runtime API error")]
+	RuntimeRequest(RuntimeApiError),
+
+	/// We tried fetching a session info which was not available.
+	#[error("There was no session with the given index")]
+	NoSuchSession(SessionIndex),
+}
+
+/// Receive a response from a runtime request and convert errors.
+pub(crate) async fn recv_runtime<V>(
+	r: oneshot::Receiver<std::result::Result<V, RuntimeApiError>>,
+) -> std::result::Result<V, Error> {
+	r.await
+		.map_err(Error::RuntimeRequestCanceled)?
+		.map_err(Error::RuntimeRequest)
+}

polkadot/node/subsystem-util/src/runtime/mod.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
 
-//! Convenient interface to the runtime.
+//! Convenient interface to runtime information.
 
 use lru::LruCache;
 
@@ -22,18 +22,20 @@ use sp_application_crypto::AppKey;
 use sp_core::crypto::Public;
 use sp_keystore::{CryptoStore, SyncCryptoStorePtr};
 
-use polkadot_node_subsystem_util::{
+use polkadot_primitives::v1::{GroupIndex, Hash, SessionIndex, SessionInfo, ValidatorId, ValidatorIndex};
+use polkadot_node_subsystem::SubsystemContext;
+
+use crate::{
 	request_session_index_for_child, request_session_info,
 };
-use polkadot_primitives::v1::{GroupIndex, Hash, SessionIndex, SessionInfo, ValidatorId, ValidatorIndex};
-use polkadot_subsystem::SubsystemContext;
 
-use super::{
-	error::recv_runtime,
-	Error,
-};
+/// Errors that can happen on runtime fetches.
+mod error;
 
-/// Caching of session info as needed by availability distribution.
+use error::{recv_runtime, Result};
+pub use error::Error;
+
+/// Caching of session info.
 ///
 /// It should be ensured that a cached session stays live in the cache as long as we might need it.
 pub struct Runtime {
@@ -72,8 +74,8 @@ impl Runtime {
 	/// Create a new `Runtime` for convenient runtime fetches.
 	pub fn new(keystore: SyncCryptoStorePtr) -> Self {
 		Self {
-			// 5 relatively conservative, 1 to 2 should suffice:
-			session_index_cache: LruCache::new(5),
+			// Adjust, depending on how many forks we want to support.
+			session_index_cache: LruCache::new(10),
 			// We need to cache the current and the last session the most:
 			session_info_cache: LruCache::new(2),
 			keystore,
@@ -85,7 +87,7 @@ impl Runtime {
 		&mut self,
 		ctx: &mut Context,
 		parent: Hash,
-	) -> Result<SessionIndex, Error>
+	) -> Result<SessionIndex>
 	where
 		Context: SubsystemContext,
 	{
@@ -106,7 +108,7 @@ impl Runtime {
 		&'a mut self,
 		ctx: &mut Context,
 		parent: Hash,
-	) -> Result<&'a ExtendedSessionInfo, Error>
+	) -> Result<&'a ExtendedSessionInfo>
 	where
 		Context: SubsystemContext,
 	{
@@ -124,7 +126,7 @@ impl Runtime {
 		ctx: &mut Context,
 		parent: Hash,
 		session_index: SessionIndex,
-	) -> Result<&'a ExtendedSessionInfo, Error>
+	) -> Result<&'a ExtendedSessionInfo>
 	where
 		Context: SubsystemContext,
 	{
@@ -155,7 +157,7 @@ impl Runtime {
 	async fn get_validator_info(
 		&self,
 		session_info: &SessionInfo,
-	) -> Result<ValidatorInfo, Error>
+	) -> Result<ValidatorInfo>
 	{
 		if let Some(our_index) = self.get_our_index(&session_info.validators).await {
 			// Get our group index:

polkadot/node/subsystem/src/messages/network_bridge_event.rs

@@ -17,13 +17,15 @@
 use std::convert::TryFrom;
 
 pub use sc_network::{ReputationChange, PeerId};
+
 use polkadot_node_network_protocol::{WrongVariant, ObservedRole, OurView, View};
+use polkadot_primitives::v1::AuthorityDiscoveryId;
 
 /// Events from network.
 #[derive(Debug, Clone, PartialEq)]
 pub enum NetworkBridgeEvent<M> {
 	/// A peer has connected.
-	PeerConnected(PeerId, ObservedRole),
+	PeerConnected(PeerId, ObservedRole, Option<AuthorityDiscoveryId>),
 
 	/// A peer has disconnected.
 	PeerDisconnected(PeerId),
@@ -58,8 +60,8 @@ impl<M> NetworkBridgeEvent<M> {
 		where T: 'a + Clone, &'a T: TryFrom<&'a M, Error = WrongVariant>
 	{
 		Ok(match *self {
-			NetworkBridgeEvent::PeerConnected(ref peer, ref role)
-				=> NetworkBridgeEvent::PeerConnected(peer.clone(), role.clone()),
+			NetworkBridgeEvent::PeerConnected(ref peer, ref role, ref authority_id)
+				=> NetworkBridgeEvent::PeerConnected(peer.clone(), role.clone(), authority_id.clone()),
 			NetworkBridgeEvent::PeerDisconnected(ref peer)
 				=> NetworkBridgeEvent::PeerDisconnected(peer.clone()),
 			NetworkBridgeEvent::PeerMessage(ref peer, ref msg)