Signed extension to refund relayer at the target chain (#1657)

* add utlity pallet to the Millau runtime

* RefundRelayerForMessagesDeliveryFromParachain prototype

* done with RefundRelayerForMessagesDeliveryFromParachain::post_dispatch

* parse calls

* check batch for obsolete headers/messages

* fmt

* shorten generic arg names + add parachain id generic arg

* check lane_id

* impl all state read functions

* fix typos from review

* renamed extension + reference issue from TODO

* tests for pre-dispaytch

* renamed extension source file

* tests for post-dispatch

* abstract fee calculation

* clippy

* actually fix clippy

* Update bin/runtime-common/src/refund_relayer_extension.rs

Co-authored-by: Adrian Catangiu <adrian@parity.io>

* Update bin/runtime-common/src/refund_relayer_extension.rs

Co-authored-by: Adrian Catangiu <adrian@parity.io>

* Update bin/runtime-common/src/refund_relayer_extension.rs

Co-authored-by: Adrian Catangiu <adrian@parity.io>

* Update bin/runtime-common/src/refund_relayer_extension.rs

Co-authored-by: Adrian Catangiu <adrian@parity.io>

Co-authored-by: Adrian Catangiu <adrian@parity.io>

bridges/modules/grandpa/src/lib.rs

@@ -540,6 +540,13 @@ pub mod pallet {
 	}
 }
 
+impl<T: Config<I>, I: 'static> Pallet<T, I> {
+	/// Get the best finalized block number.
+	pub fn best_finalized_number() -> Option<BridgedBlockNumber<T, I>> {
+		BestFinalized::<T, I>::get().map(|id| id.number())
+	}
+}
+
 /// Bridge GRANDPA pallet as header chain.
 pub type GrandpaChainHeaders<T, I> = Pallet<T, I>;
 

bridges/modules/messages/src/lib.rs

@@ -168,10 +168,10 @@ pub mod pallet {
 	}
 
 	/// Shortcut to messages proof type for Config.
-	type MessagesProofOf<T, I> =
+	pub type MessagesProofOf<T, I> =
 		<<T as Config<I>>::SourceHeaderChain as SourceHeaderChain>::MessagesProof;
 	/// Shortcut to messages delivery proof type for Config.
-	type MessagesDeliveryProofOf<T, I> =
+	pub type MessagesDeliveryProofOf<T, I> =
 		<<T as Config<I>>::TargetHeaderChain as TargetHeaderChain<
 			<T as Config<I>>::OutboundPayload,
 			<T as frame_system::Config>::AccountId,
@@ -631,6 +631,11 @@ pub mod pallet {
 				dispatch_weight: T::MessageDispatch::dispatch_weight(&mut dispatch_message),
 			}
 		}
+
+		/// Return inbound lane data.
+		pub fn inbound_lane_data(lane: LaneId) -> InboundLaneData<T::InboundRelayer> {
+			InboundLanes::<T, I>::get(lane).0
+		}
 	}
 }
 

bridges/modules/parachains/src/lib.rs

@@ -401,6 +401,11 @@ pub mod pallet {
 	}
 
 	impl<T: Config<I>, I: 'static> Pallet<T, I> {
+		/// Get stored parachain info.
+		pub fn best_parachain_info(parachain: ParaId) -> Option<ParaInfo> {
+			ParasInfo::<T, I>::get(parachain)
+		}
+
 		/// Get best finalized header of the given parachain.
 		pub fn best_parachain_head(parachain: ParaId) -> Option<ParaHead> {
 			let best_para_head_hash = ParasInfo::<T, I>::get(parachain)?.best_head_hash.head_hash;

bridges/modules/relayers/Cargo.toml

@@ -22,6 +22,7 @@ frame-benchmarking = { git = "https://github.com/paritytech/substrate", branch =
 frame-support = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 frame-system = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 sp-arithmetic = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 sp-std = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 
 [dev-dependencies]
@@ -42,6 +43,7 @@ std = [
 	"log/std",
 	"scale-info/std",
 	"sp-arithmetic/std",
+	"sp-runtime/std",
 	"sp-std/std",
 ]
 runtime-benchmarks = [

bridges/modules/relayers/src/lib.rs

@@ -109,8 +109,9 @@ pub mod pallet {
 
 				log::trace!(
 					target: crate::LOG_TARGET,
-					"Relayer {:?} can now claim reward: {:?}",
+					"Relayer {:?} can now claim reward for serving lane {:?}: {:?}",
 					relayer,
+					lane_id,
 					new_reward,
 				);
 			});
@@ -141,6 +142,7 @@ pub mod pallet {
 
 	/// Map of the relayer => accumulated reward.
 	#[pallet::storage]
+	#[pallet::getter(fn relayer_reward)]
 	pub type RelayerRewards<T: Config> = StorageDoubleMap<
 		_,
 		Blake2_128Concat,