add NodeFeatures field to HostConfiguration and runtime API (#2177)

Adds a `NodeFeatures` bitfield value to the runtime `HostConfiguration`,
with the purpose of coordinating the enabling of node-side features,
such as: https://github.com/paritytech/polkadot-sdk/issues/628 and
https://github.com/paritytech/polkadot-sdk/issues/598.
These are features that require all validators enable them at the same
time, assuming all/most nodes have upgraded their node versions.

This PR doesn't add any feature yet. These are coming in future PRs.

Also adds a runtime API for querying the state of the client features
and an extrinsic for setting/unsetting a feature by its index in the bitfield.

Note: originally part of:
https://github.com/paritytech/polkadot-sdk/pull/1644, but posted as
standalone to be reused by other PRs until the initial PR is merged

polkadot/node/core/runtime-api/src/cache.rs

@@ -20,7 +20,7 @@ use schnellru::{ByLength, LruMap};
 use sp_consensus_babe::Epoch;
 
 use polkadot_primitives::{
-	async_backing, slashing, AuthorityDiscoveryId, BlockNumber, CandidateCommitments,
+	async_backing, slashing, vstaging, AuthorityDiscoveryId, BlockNumber, CandidateCommitments,
 	CandidateEvent, CandidateHash, CommittedCandidateReceipt, CoreState, DisputeState,
 	ExecutorParams, GroupRotationInfo, Hash, Id as ParaId, InboundDownwardMessage,
 	InboundHrmpMessage, OccupiedCoreAssumption, PersistedValidationData, PvfCheckStatement,
@@ -67,6 +67,7 @@ pub(crate) struct RequestResultCache {
 	disabled_validators: LruMap<Hash, Vec<ValidatorIndex>>,
 	para_backing_state: LruMap<(Hash, ParaId), Option<async_backing::BackingState>>,
 	async_backing_params: LruMap<Hash, async_backing::AsyncBackingParams>,
+	node_features: LruMap<SessionIndex, vstaging::NodeFeatures>,
 }
 
 impl Default for RequestResultCache {
@@ -100,6 +101,7 @@ impl Default for RequestResultCache {
 			disabled_validators: LruMap::new(ByLength::new(DEFAULT_CACHE_CAP)),
 			para_backing_state: LruMap::new(ByLength::new(DEFAULT_CACHE_CAP)),
 			async_backing_params: LruMap::new(ByLength::new(DEFAULT_CACHE_CAP)),
+			node_features: LruMap::new(ByLength::new(DEFAULT_CACHE_CAP)),
 		}
 	}
 }
@@ -446,6 +448,21 @@ impl RequestResultCache {
 		self.minimum_backing_votes.insert(session_index, minimum_backing_votes);
 	}
 
+	pub(crate) fn node_features(
+		&mut self,
+		session_index: SessionIndex,
+	) -> Option<&vstaging::NodeFeatures> {
+		self.node_features.get(&session_index).map(|f| &*f)
+	}
+
+	pub(crate) fn cache_node_features(
+		&mut self,
+		session_index: SessionIndex,
+		features: vstaging::NodeFeatures,
+	) {
+		self.node_features.insert(session_index, features);
+	}
+
 	pub(crate) fn disabled_validators(
 		&mut self,
 		relay_parent: &Hash,
@@ -540,4 +557,5 @@ pub(crate) enum RequestResult {
 	DisabledValidators(Hash, Vec<ValidatorIndex>),
 	ParaBackingState(Hash, ParaId, Option<async_backing::BackingState>),
 	AsyncBackingParams(Hash, async_backing::AsyncBackingParams),
+	NodeFeatures(SessionIndex, vstaging::NodeFeatures),
 }

polkadot/node/core/runtime-api/src/lib.rs

@@ -173,6 +173,8 @@ where
 				.cache_para_backing_state((relay_parent, para_id), constraints),
 			AsyncBackingParams(relay_parent, params) =>
 				self.requests_cache.cache_async_backing_params(relay_parent, params),
+			NodeFeatures(session_index, params) =>
+				self.requests_cache.cache_node_features(session_index, params),
 		}
 	}
 
@@ -313,6 +315,15 @@ where
 					Some(Request::MinimumBackingVotes(index, sender))
 				}
 			},
+			Request::NodeFeatures(index, sender) => {
+				if let Some(value) = self.requests_cache.node_features(index) {
+					self.metrics.on_cached_request();
+					let _ = sender.send(Ok(value.clone()));
+					None
+				} else {
+					Some(Request::NodeFeatures(index, sender))
+				}
+			},
 		}
 	}
 
@@ -408,6 +419,9 @@ where
 
 	macro_rules! query {
 		($req_variant:ident, $api_name:ident ($($param:expr),*), ver = $version:expr, $sender:expr) => {{
+			query!($req_variant, $api_name($($param),*), ver = $version, $sender, result = ( relay_parent $(, $param )* ) )
+		}};
+		($req_variant:ident, $api_name:ident ($($param:expr),*), ver = $version:expr, $sender:expr, result = ( $($results:expr),* ) ) => {{
 			let sender = $sender;
 			let version: u32 = $version;	// enforce type for the version expression
 			let runtime_version = client.api_version_parachain_host(relay_parent).await
@@ -441,7 +455,7 @@ where
 			metrics.on_request(res.is_ok());
 			let _ = sender.send(res.clone());
 
-			res.ok().map(|res| RequestResult::$req_variant(relay_parent, $( $param, )* res))
+			res.ok().map(|res| RequestResult::$req_variant($( $results, )* res))
 		}}
 	}
 
@@ -591,5 +605,12 @@ where
 				sender
 			)
 		},
+		Request::NodeFeatures(index, sender) => query!(
+			NodeFeatures,
+			node_features(),
+			ver = Request::NODE_FEATURES_RUNTIME_REQUIREMENT,
+			sender,
+			result = (index)
+		),
 	}
 }

polkadot/node/core/runtime-api/src/tests.rs

@@ -20,12 +20,12 @@ use polkadot_node_primitives::{BabeAllowedSlots, BabeEpoch, BabeEpochConfigurati
 use polkadot_node_subsystem::SpawnGlue;
 use polkadot_node_subsystem_test_helpers::make_subsystem_context;
 use polkadot_primitives::{
-	async_backing, slashing, AuthorityDiscoveryId, BlockNumber, CandidateCommitments,
-	CandidateEvent, CandidateHash, CommittedCandidateReceipt, CoreState, DisputeState,
-	ExecutorParams, GroupRotationInfo, Id as ParaId, InboundDownwardMessage, InboundHrmpMessage,
-	OccupiedCoreAssumption, PersistedValidationData, PvfCheckStatement, ScrapedOnChainVotes,
-	SessionIndex, SessionInfo, Slot, ValidationCode, ValidationCodeHash, ValidatorId,
-	ValidatorIndex, ValidatorSignature,
+	async_backing, slashing, vstaging::NodeFeatures, AuthorityDiscoveryId, BlockNumber,
+	CandidateCommitments, CandidateEvent, CandidateHash, CommittedCandidateReceipt, CoreState,
+	DisputeState, ExecutorParams, GroupRotationInfo, Id as ParaId, InboundDownwardMessage,
+	InboundHrmpMessage, OccupiedCoreAssumption, PersistedValidationData, PvfCheckStatement,
+	ScrapedOnChainVotes, SessionIndex, SessionInfo, Slot, ValidationCode, ValidationCodeHash,
+	ValidatorId, ValidatorIndex, ValidatorSignature,
 };
 use sp_api::ApiError;
 use sp_core::testing::TaskExecutor;
@@ -269,6 +269,10 @@ impl RuntimeApiSubsystemClient for MockSubsystemClient {
 		todo!("Not required for tests")
 	}
 
+	async fn node_features(&self, _: Hash) -> Result<NodeFeatures, ApiError> {
+		todo!("Not required for tests")
+	}
+
 	async fn disabled_validators(&self, _: Hash) -> Result<Vec<ValidatorIndex>, ApiError> {
 		todo!("Not required for tests")
 	}

polkadot/node/subsystem-types/src/messages.rs

@@ -42,12 +42,12 @@ use polkadot_node_primitives::{
 	ValidationResult,
 };
 use polkadot_primitives::{
-	async_backing, slashing, AuthorityDiscoveryId, BackedCandidate, BlockNumber, CandidateEvent,
-	CandidateHash, CandidateIndex, CandidateReceipt, CollatorId, CommittedCandidateReceipt,
-	CoreState, DisputeState, ExecutorParams, GroupIndex, GroupRotationInfo, Hash,
-	Header as BlockHeader, Id as ParaId, InboundDownwardMessage, InboundHrmpMessage,
-	MultiDisputeStatementSet, OccupiedCoreAssumption, PersistedValidationData, PvfCheckStatement,
-	PvfExecTimeoutKind, SessionIndex, SessionInfo, SignedAvailabilityBitfield,
+	async_backing, slashing, vstaging::NodeFeatures, AuthorityDiscoveryId, BackedCandidate,
+	BlockNumber, CandidateEvent, CandidateHash, CandidateIndex, CandidateReceipt, CollatorId,
+	CommittedCandidateReceipt, CoreState, DisputeState, ExecutorParams, GroupIndex,
+	GroupRotationInfo, Hash, Header as BlockHeader, Id as ParaId, InboundDownwardMessage,
+	InboundHrmpMessage, MultiDisputeStatementSet, OccupiedCoreAssumption, PersistedValidationData,
+	PvfCheckStatement, PvfExecTimeoutKind, SessionIndex, SessionInfo, SignedAvailabilityBitfield,
 	SignedAvailabilityBitfields, ValidationCode, ValidationCodeHash, ValidatorId, ValidatorIndex,
 	ValidatorSignature,
 };
@@ -718,6 +718,8 @@ pub enum RuntimeApiRequest {
 	///
 	/// If it's not supported by the Runtime, the async backing is said to be disabled.
 	AsyncBackingParams(RuntimeApiSender<async_backing::AsyncBackingParams>),
+	/// Get the node features.
+	NodeFeatures(SessionIndex, RuntimeApiSender<NodeFeatures>),
 }
 
 impl RuntimeApiRequest {
@@ -746,6 +748,9 @@ impl RuntimeApiRequest {
 
 	/// `DisabledValidators`
 	pub const DISABLED_VALIDATORS_RUNTIME_REQUIREMENT: u32 = 8;
+
+	/// `Node features`
+	pub const NODE_FEATURES_RUNTIME_REQUIREMENT: u32 = 9;
 }
 
 /// A message to the Runtime API subsystem.

polkadot/node/subsystem-types/src/runtime_client.rs

@@ -16,12 +16,12 @@
 
 use async_trait::async_trait;
 use polkadot_primitives::{
-	async_backing, runtime_api::ParachainHost, slashing, Block, BlockNumber, CandidateCommitments,
-	CandidateEvent, CandidateHash, CommittedCandidateReceipt, CoreState, DisputeState,
-	ExecutorParams, GroupRotationInfo, Hash, Id, InboundDownwardMessage, InboundHrmpMessage,
-	OccupiedCoreAssumption, PersistedValidationData, PvfCheckStatement, ScrapedOnChainVotes,
-	SessionIndex, SessionInfo, ValidationCode, ValidationCodeHash, ValidatorId, ValidatorIndex,
-	ValidatorSignature,
+	async_backing, runtime_api::ParachainHost, slashing, vstaging, Block, BlockNumber,
+	CandidateCommitments, CandidateEvent, CandidateHash, CommittedCandidateReceipt, CoreState,
+	DisputeState, ExecutorParams, GroupRotationInfo, Hash, Id, InboundDownwardMessage,
+	InboundHrmpMessage, OccupiedCoreAssumption, PersistedValidationData, PvfCheckStatement,
+	ScrapedOnChainVotes, SessionIndex, SessionInfo, ValidationCode, ValidationCodeHash,
+	ValidatorId, ValidatorIndex, ValidatorSignature,
 };
 use sc_transaction_pool_api::OffchainTransactionPoolFactory;
 use sp_api::{ApiError, ApiExt, ProvideRuntimeApi};
@@ -257,8 +257,14 @@ pub trait RuntimeApiSubsystemClient {
 	) -> Result<Option<async_backing::BackingState>, ApiError>;
 
 	// === v8 ===
+
 	/// Gets the disabled validators at a specific block height
 	async fn disabled_validators(&self, at: Hash) -> Result<Vec<ValidatorIndex>, ApiError>;
+
+	// === v9 ===
+
+	/// Get the node features.
+	async fn node_features(&self, at: Hash) -> Result<vstaging::NodeFeatures, ApiError>;
 }
 
 /// Default implementation of [`RuntimeApiSubsystemClient`] using the client.
@@ -508,6 +514,10 @@ where
 		self.client.runtime_api().async_backing_params(at)
 	}
 
+	async fn node_features(&self, at: Hash) -> Result<vstaging::NodeFeatures, ApiError> {
+		self.client.runtime_api().node_features(at)
+	}
+
 	async fn disabled_validators(&self, at: Hash) -> Result<Vec<ValidatorIndex>, ApiError> {
 		self.client.runtime_api().disabled_validators(at)
 	}

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

@@ -30,8 +30,8 @@ use polkadot_node_subsystem::{
 };
 use polkadot_node_subsystem_types::UnpinHandle;
 use polkadot_primitives::{
-	slashing, AsyncBackingParams, CandidateEvent, CandidateHash, CoreState, EncodeAs,
-	ExecutorParams, GroupIndex, GroupRotationInfo, Hash, IndexedVec, OccupiedCore,
+	slashing, vstaging::NodeFeatures, AsyncBackingParams, CandidateEvent, CandidateHash, CoreState,
+	EncodeAs, ExecutorParams, GroupIndex, GroupRotationInfo, Hash, IndexedVec, OccupiedCore,
 	ScrapedOnChainVotes, SessionIndex, SessionInfo, Signed, SigningContext, UncheckedSigned,
 	ValidationCode, ValidationCodeHash, ValidatorId, ValidatorIndex, LEGACY_MIN_BACKING_VOTES,
 };
@@ -507,3 +507,32 @@ pub async fn request_min_backing_votes(
 		min_backing_votes_res
 	}
 }
+
+/// Request the node features enabled in the runtime.
+/// Pass in the session index for caching purposes, as it should only change on session boundaries.
+/// Prior to runtime API version 9, just return `None`.
+pub async fn request_node_features(
+	parent: Hash,
+	session_index: SessionIndex,
+	sender: &mut impl overseer::SubsystemSender<RuntimeApiMessage>,
+) -> Result<Option<NodeFeatures>> {
+	let res = recv_runtime(
+		request_from_runtime(parent, sender, |tx| {
+			RuntimeApiRequest::NodeFeatures(session_index, tx)
+		})
+		.await,
+	)
+	.await;
+
+	if let Err(Error::RuntimeRequest(RuntimeApiError::NotSupported { .. })) = res {
+		gum::trace!(
+			target: LOG_TARGET,
+			?parent,
+			"Querying the node features from the runtime is not supported by the current Runtime API",
+		);
+
+		Ok(None)
+	} else {
+		res.map(Some)
+	}
+}