Add Bridge Header Sync to Rococo Runtime (#2983)

* Add bridges code to workspace

* Add Rococo and Wococo bridge instances to Rococo runtime

* Add Rococo and Wococo runtime APIs

* Add GenesisConfig parameters for bridge pallet

* Update Rococo spec_version used by bridge relayer

* Add scripts for running Rococo and Wococo dev nodes

* Add scripts for running Rococo<>Wococo header sync

* Apply patch for build artifact location

* Remove bridges crates from workspace

* Downgrade async related dependencies

* Change bridge pallet owner to be `root_key`

* Bump number of `MaxRequests` allowed

* Revert changes in `bridges` subtree folder

* Use correct account for Sudo

* Add comment explaining duplicate bridge pallets

* Remove WeightInfo comment.

Co-authored-by: Tomasz Drwięga <tomasz@parity.io>

polkadot/runtime/rococo/Cargo.toml

@@ -68,6 +68,11 @@ xcm-executor = { package = "xcm-executor", path = "../../xcm/xcm-executor", defa
 xcm-builder = { package = "xcm-builder", path = "../../xcm/xcm-builder", default-features = false }
 pallet-xcm = { path = "../../xcm/pallet-xcm", default-features = false }
 
+# Bridge Dependencies
+bp-rococo = { path = "../../bridges/primitives/chain-rococo", default-features = false }
+bp-wococo = { path = "../../bridges/primitives/chain-wococo", default-features = false }
+pallet-bridge-grandpa = { path = "../../bridges/modules/grandpa", default-features = false }
+
 [build-dependencies]
 substrate-wasm-builder = "3.0.0"
 
@@ -77,6 +82,8 @@ no_std = []
 std = [
 	"authority-discovery-primitives/std",
 	"babe-primitives/std",
+	"bp-rococo/std",
+	"bp-wococo/std",
 	"parity-scale-codec/std",
 	"frame-executive/std",
 	"pallet-authority-discovery/std",
@@ -84,6 +91,7 @@ std = [
 	"pallet-babe/std",
 	"beefy-primitives/std",
 	"pallet-balances/std",
+	"pallet-bridge-grandpa/std",
 	"pallet-collective/std",
 	"pallet-beefy/std",
 	"pallet-grandpa/std",

polkadot/runtime/rococo/src/lib.rs

@@ -236,6 +236,12 @@ construct_runtime! {
 		Beefy: pallet_beefy::{Pallet, Config<T>, Storage},
 		MmrLeaf: mmr_common::{Pallet, Storage},
 
+		// It might seem strange that we add both sides of the bridge to the same runtime. We do this because this
+		// runtime as shared by both the Rococo and Wococo chains. When running as Rococo we only use
+		// `BridgeWococoGrandpa`, and vice versa.
+		BridgeRococoGrandpa: pallet_bridge_grandpa::{Pallet, Call, Storage, Config<T>} = 40,
+		BridgeWococoGrandpa: pallet_bridge_grandpa::<Instance1>::{Pallet, Call, Storage, Config<T>} = 41,
+
 		// Validator Manager pallet.
 		ValidatorManager: validator_manager::{Pallet, Call, Storage, Event<T>},
 
@@ -794,6 +800,38 @@ impl mmr_common::Config for Runtime {
 	type ParachainHeads = Paras;
 }
 
+parameter_types! {
+	// This is a pretty unscientific cap.
+	//
+	// Note that once this is hit the pallet will essentially throttle incoming requests down to one
+	// call per block.
+	pub const MaxRequests: u32 = 4 * HOURS as u32;
+
+	// Number of headers to keep.
+	//
+	// Assuming the worst case of every header being finalized, we will keep headers at least for a
+	// week.
+	pub const HeadersToKeep: u32 = 7 * DAYS as u32;
+}
+
+pub type RococoGrandpaInstance = ();
+impl pallet_bridge_grandpa::Config for Runtime {
+	type BridgedChain = bp_rococo::Rococo;
+	type MaxRequests = MaxRequests;
+	type HeadersToKeep = HeadersToKeep;
+
+	type WeightInfo = pallet_bridge_grandpa::weights::RialtoWeight<Runtime>;
+}
+
+pub type WococoGrandpaInstance = pallet_bridge_grandpa::Instance1;
+impl pallet_bridge_grandpa::Config<WococoGrandpaInstance> for Runtime {
+	type BridgedChain = bp_wococo::Wococo;
+	type MaxRequests = MaxRequests;
+	type HeadersToKeep = HeadersToKeep;
+
+	type WeightInfo = pallet_bridge_grandpa::weights::RialtoWeight<Runtime>;
+}
+
 impl Randomness<Hash, BlockNumber> for ParentHashRandomness {
 	fn random(subject: &[u8]) -> (Hash, BlockNumber) {
 		(
@@ -1222,6 +1260,28 @@ sp_api::impl_runtime_apis! {
 		}
 	}
 
+	impl bp_rococo::RococoFinalityApi<Block> for Runtime {
+		fn best_finalized() -> (bp_rococo::BlockNumber, bp_rococo::Hash) {
+			let header = BridgeRococoGrandpa::best_finalized();
+			(header.number, header.hash())
+		}
+
+		fn is_known_header(hash: bp_rococo::Hash) -> bool {
+			BridgeRococoGrandpa::is_known_header(hash)
+		}
+	}
+
+	impl bp_wococo::WococoFinalityApi<Block> for Runtime {
+		fn best_finalized() -> (bp_wococo::BlockNumber, bp_wococo::Hash) {
+			let header = BridgeWococoGrandpa::best_finalized();
+			(header.number, header.hash())
+		}
+
+		fn is_known_header(hash: bp_wococo::Hash) -> bool {
+			BridgeWococoGrandpa::is_known_header(hash)
+		}
+	}
+
 	impl frame_system_rpc_runtime_api::AccountNonceApi<Block, AccountId, Nonce> for Runtime {
 		fn account_nonce(account: AccountId) -> Nonce {
 			System::account_nonce(account)