Bound finalized header, execution header and sync committee by pruning older data beyond threshold

parachain/pallets/ethereum-beacon-client/Cargo.toml

@@ -34,6 +34,7 @@ snowbridge-ethereum = { path = "../../primitives/ethereum", default-features = f
 snowbridge-beacon-primitives = { path = "../../primitives/beacon", default-features = false }
 
 [dev-dependencies]
+rand = "0.8.5"
 sp-keyring = { git = "https://github.com/paritytech/substrate.git", branch = "master" }
 snowbridge-testutils = { path = "../../primitives/testutils" }
 serde_json = "1.0.96"

parachain/pallets/ethereum-beacon-client/src/lib.rs

@@ -97,8 +97,14 @@ pub mod pallet {
 		type MaxSlotsPerHistoricalRoot: Get<u64>;
 		#[pallet::constant]
 		type MaxFinalizedHeaderSlotArray: Get<u32>;
+		/// Maximum execution headers to be stored
+		#[pallet::constant]
+		type ExecutionHeadersPruneThreshold: Get<u64>;
 		#[pallet::constant]
 		type ForkVersions: Get<ForkVersions>;
+		/// Maximum sync committees to be stored
+		#[pallet::constant]
+		type SyncCommitteePruneThreshold: Get<u64>;
 		type WeightInfo: WeightInfo;
 		type WeakSubjectivityPeriodSeconds: Get<u64>;
 	}
@@ -165,21 +171,31 @@ pub mod pallet {
 
 	#[pallet::storage]
 	pub(super) type FinalizedBeaconHeaderSlots<T: Config> =
-		StorageValue<_, BoundedVec<u64, T::MaxFinalizedHeaderSlotArray>, ValueQuery>;
+		StorageValue<_, BoundedVec<(u64, H256), T::MaxFinalizedHeaderSlotArray>, ValueQuery>;
 
 	#[pallet::storage]
 	pub(super) type FinalizedBeaconHeadersBlockRoot<T: Config> =
 		StorageMap<_, Identity, H256, H256, ValueQuery>;
 
+	/// Header mapping bounds. Used by pruning algorithm to prune oldest value and add
+	/// latest value.
+	#[pallet::storage]
+	pub(super) type ExecutionHeadersOldestMapping<T: Config> =
+		StorageValue<_, (u64, u64), OptionQuery>;
+
+	/// Mapping of count -> Execution header hash. Used to prune older headers
+	#[pallet::storage]
+	pub(super) type ExecutionHeadersMapping<T: Config> =
+		StorageMap<_, Identity, u64, H256, ValueQuery>;
+
 	#[pallet::storage]
 	pub(super) type ExecutionHeaders<T: Config> =
-		StorageMap<_, Identity, H256, ExecutionHeader, OptionQuery>;
+		CountedStorageMap<_, Identity, H256, ExecutionHeader, OptionQuery>;
 
 	/// Current sync committee corresponding to the active header.
-	/// TODO  prune older sync committees than xxx
 	#[pallet::storage]
 	pub(super) type SyncCommittees<T: Config> =
-		StorageMap<_, Identity, u64, SyncCommitteeOf<T>, ValueQuery>;
+		CountedStorageMap<_, Identity, u64, SyncCommitteeOf<T>, ValueQuery>;
 
 	#[pallet::storage]
 	pub(super) type ValidatorsRoot<T: Config> = StorageValue<_, H256, ValueQuery>;
@@ -384,7 +400,7 @@ pub mod pallet {
 			};
 
 			<FinalizedBeaconHeaders<T>>::insert(block_root, initial_sync.header);
-			Self::add_finalized_header_slot(slot)?;
+			Self::add_finalized_header_slot(slot, block_root)?;
 			<LatestFinalizedHeaderState<T>>::set(last_finalized_header);
 
 			Ok(())
@@ -864,7 +880,7 @@ pub mod pallet {
 			Ok(())
 		}
 
-		fn store_sync_committee(period: u64, sync_committee: SyncCommitteeOf<T>) {
+		pub(crate) fn store_sync_committee(period: u64, sync_committee: SyncCommitteeOf<T>) {
 			<SyncCommittees<T>>::insert(period, sync_committee);
 
 			log::trace!(
@@ -874,15 +890,39 @@ pub mod pallet {
 			);
 
 			<LatestSyncCommitteePeriod<T>>::set(period);
+			Self::prune_older_sync_committees();
 
 			Self::deposit_event(Event::SyncCommitteeUpdated { period });
 		}
 
+		// Contract: It is assumed that the light client do not skip sync committee.
+		fn prune_older_sync_committees() {
+			let threshold = T::SyncCommitteePruneThreshold::get();
+			let stored_sync_committees = <SyncCommittees<T>>::count();
+
+			if stored_sync_committees as u64 > threshold {
+				let latest_sync_committee_period = <LatestSyncCommitteePeriod<T>>::get();
+				let highest_period_to_remove = latest_sync_committee_period - threshold;
+
+				let mut current_sync_committee_to_remove = highest_period_to_remove;
+				let mut number_of_sync_committees_to_remove =
+					stored_sync_committees as u64 - threshold;
+
+				while number_of_sync_committees_to_remove > 0 {
+					<SyncCommittees<T>>::remove(current_sync_committee_to_remove);
+					number_of_sync_committees_to_remove =
+						number_of_sync_committees_to_remove.saturating_sub(1);
+					current_sync_committee_to_remove =
+						current_sync_committee_to_remove.saturating_sub(1);
+				}
+			}
+		}
+
 		fn store_finalized_header(block_root: Root, header: BeaconHeader) -> DispatchResult {
 			let slot = header.slot;
 
 			<FinalizedBeaconHeaders<T>>::insert(block_root, header);
-			Self::add_finalized_header_slot(slot)?;
+			Self::add_finalized_header_slot(slot, block_root)?;
 
 			log::info!(
 				target: "ethereum-beacon-client",
@@ -902,27 +942,39 @@ pub mod pallet {
 			Ok(())
 		}
 
-		fn add_finalized_header_slot(slot: u64) -> DispatchResult {
+		pub(super) fn add_finalized_header_slot(
+			slot: u64,
+			finalized_header_hash: H256,
+		) -> DispatchResult {
 			<FinalizedBeaconHeaderSlots<T>>::try_mutate(|b_vec| {
 				if b_vec.len() as u32 == T::MaxFinalizedHeaderSlotArray::get() {
-					b_vec.remove(0);
+					let (_slot, finalized_header_hash) = b_vec.remove(0);
+					// Removing corresponding finalized header data of popped slot
+					// as that data will not be used by relayer anyway.
+					<FinalizedBeaconHeadersBlockRoot<T>>::remove(finalized_header_hash);
+					<FinalizedBeaconHeaders<T>>::remove(finalized_header_hash);
+					<FinalizedBeaconHeadersBlockRoot<T>>::remove(finalized_header_hash);
 				}
-				b_vec.try_push(slot)
+				b_vec.try_push((slot, finalized_header_hash))
 			})
 			.map_err(|_| <Error<T>>::FinalizedBeaconHeaderSlotsExceeded)?;
 
 			Ok(())
 		}
 
-		fn store_execution_header(
+		pub(super) fn store_execution_header(
 			block_hash: H256,
 			header: ExecutionHeader,
 			beacon_slot: u64,
 			beacon_block_root: H256,
 		) {
 			let block_number = header.block_number;
 
+			let (_, latest_mapping_to_insert) = Self::get_mapping_bound();
+			<ExecutionHeadersMapping<T>>::insert(latest_mapping_to_insert, block_hash);
+			Self::update_mapping_bound(None, Some(latest_mapping_to_insert + 1));
 			<ExecutionHeaders<T>>::insert(block_hash, header);
+			Self::prune_older_execution_headers();
 
 			log::trace!(
 				target: "ethereum-beacon-client",
@@ -941,6 +993,37 @@ pub mod pallet {
 			Self::deposit_event(Event::ExecutionHeaderImported { block_hash, block_number });
 		}
 
+		fn get_mapping_bound() -> (u64, u64) {
+			<ExecutionHeadersOldestMapping<T>>::get().unwrap_or((1, 1))
+		}
+
+		fn update_mapping_bound(oldest: Option<u64>, latest: Option<u64>) {
+			let (previous_oldest, previous_latest) =
+				<ExecutionHeadersOldestMapping<T>>::get().unwrap_or((1, 1));
+			let new_oldest = oldest.unwrap_or(previous_oldest);
+			let new_latest = latest.unwrap_or(previous_latest);
+			<ExecutionHeadersOldestMapping<T>>::put((new_oldest, new_latest));
+		}
+
+		fn prune_older_execution_headers() {
+			let threshold = T::ExecutionHeadersPruneThreshold::get();
+			let stored_execution_headers = <ExecutionHeaders<T>>::count() as u64;
+
+			if stored_execution_headers > threshold {
+				let (mut oldest_mapping_to_delete, _) = Self::get_mapping_bound();
+				let execution_headers_to_delete =
+					stored_execution_headers.saturating_sub(threshold);
+				for _i in 0..execution_headers_to_delete {
+					let execution_header_hash =
+						<ExecutionHeadersMapping<T>>::get(oldest_mapping_to_delete);
+					<ExecutionHeadersMapping<T>>::remove(oldest_mapping_to_delete);
+					<ExecutionHeaders<T>>::remove(execution_header_hash);
+					oldest_mapping_to_delete += 1;
+				}
+				Self::update_mapping_bound(Some(oldest_mapping_to_delete), None);
+			}
+		}
+
 		fn store_validators_root(validators_root: H256) {
 			<ValidatorsRoot<T>>::set(validators_root);
 		}

parachain/pallets/ethereum-beacon-client/src/mock.rs

@@ -77,7 +77,9 @@ pub mod mock_minimal {
 		pub const MaxPublicKeySize: u32 = config::PUBKEY_SIZE as u32;
 		pub const MaxSignatureSize: u32 = config::SIGNATURE_SIZE as u32;
 		pub const MaxSlotsPerHistoricalRoot: u64 = 64;
-		pub const MaxFinalizedHeaderSlotArray: u32 = 1000;
+		pub const MaxFinalizedHeaderSlotArray: u32 = 12;
+		pub const SyncCommitteePruneThreshold: u64 = 4;
+		pub const ExecutionHeadersPruneThreshold: u64 = 10;
 		pub const WeakSubjectivityPeriodSeconds: u32 = 97200;
 		pub const ChainForkVersions: ForkVersions = ForkVersions{
 			genesis: Fork {
@@ -112,6 +114,8 @@ pub mod mock_minimal {
 		type MaxSlotsPerHistoricalRoot = MaxSlotsPerHistoricalRoot;
 		type MaxFinalizedHeaderSlotArray = MaxFinalizedHeaderSlotArray;
 		type ForkVersions = ChainForkVersions;
+		type SyncCommitteePruneThreshold = SyncCommitteePruneThreshold;
+		type ExecutionHeadersPruneThreshold = ExecutionHeadersPruneThreshold;
 		type WeakSubjectivityPeriodSeconds = WeakSubjectivityPeriodSeconds;
 		type WeightInfo = ();
 	}
@@ -203,6 +207,8 @@ pub mod mock_mainnet {
 				epoch: 162304,
 			},
 		};
+		pub const SyncCommitteePruneThreshold: u64 = 4;
+		pub const ExecutionHeadersPruneThreshold: u64 = 10;
 	}
 
 	impl ethereum_beacon_client::Config for Test {
@@ -218,6 +224,8 @@ pub mod mock_mainnet {
 		type MaxSlotsPerHistoricalRoot = MaxSlotsPerHistoricalRoot;
 		type MaxFinalizedHeaderSlotArray = MaxFinalizedHeaderSlotArray;
 		type ForkVersions = ChainForkVersions;
+		type SyncCommitteePruneThreshold = SyncCommitteePruneThreshold;
+		type ExecutionHeadersPruneThreshold = ExecutionHeadersPruneThreshold;
 		type WeakSubjectivityPeriodSeconds = WeakSubjectivityPeriodSeconds;
 		type WeightInfo = ();
 	}