Westend<>Rococo Headers Relay (paritytech#875)

* Add modules for Rococo<>Westend header sync

* Use mock Westend and Rococo finaltiy tx calls

* Add Westend<>Rococo variants to `init_bridge`

* Add Westend<>Rococo variants to `relay_headers`

* Simplify the Rococo and Westend signing params

* Add `submit_finality_proof` mock Call variant

* Add note to more closely match `initialize` Call variant

* Accidentally committed `cargo-expand`ed code 🤦

* Add `initialize` Call variant to Rococo mock

* Fix call enums.

* Add explainatory comment.

* clippy.

* Add issue number.

* De-duplicate metrics customisation.

* Add comments to Rococo/Westend runtimes.

* Add scale-encoding compatibility test.

* Fix tests.

* Clippy.

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

Author: HCastano

Cargo.lock

@@ -45,6 +45,7 @@ use sp_std::{fmt::Debug, marker::PhantomData, prelude::*};
 /// Spec version type.
 pub type SpecVersion = u32;
 
+// TODO [#895] move to primitives
 /// Origin of a Call when it is dispatched on the target chain.
 ///
 /// The source chain can (and should) verify that the message can be dispatched on the target chain
@@ -89,6 +90,7 @@ pub enum CallOrigin<SourceChainAccountId, TargetChainAccountPublic, TargetChainS
 	SourceAccount(SourceChainAccountId),
 }
 
+// TODO [#895] move to primitives
 /// Message payload type used by dispatch module.
 #[derive(RuntimeDebug, Encode, Decode, Clone, PartialEq, Eq)]
 pub struct MessagePayload<SourceChainAccountId, TargetChainAccountPublic, TargetChainSignature, Call> {

modules/dispatch/src/lib.rs

@@ -39,16 +39,13 @@
 use crate::weights::WeightInfo;
 
 use bp_header_chain::justification::GrandpaJustification;
+use bp_header_chain::InitializationData;
 use bp_runtime::{BlockNumberOf, Chain, HashOf, HasherOf, HeaderOf};
-use codec::{Decode, Encode};
 use finality_grandpa::voter_set::VoterSet;
 use frame_support::ensure;
 use frame_system::{ensure_signed, RawOrigin};
-#[cfg(feature = "std")]
-use serde::{Deserialize, Serialize};
 use sp_finality_grandpa::{ConsensusLog, GRANDPA_ENGINE_ID};
 use sp_runtime::traits::{BadOrigin, Header as HeaderT, Zero};
-use sp_runtime::RuntimeDebug;
 
 #[cfg(test)]
 mod mock;
@@ -511,22 +508,6 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 	}
 }
 
-/// Data required for initializing the bridge pallet.
-///
-/// The bridge needs to know where to start its sync from, and this provides that initial context.
-#[derive(Default, Encode, Decode, RuntimeDebug, PartialEq, Clone)]
-#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
-pub struct InitializationData<H: HeaderT> {
-	/// The header from which we should start syncing.
-	pub header: H,
-	/// The initial authorities of the pallet.
-	pub authority_list: sp_finality_grandpa::AuthorityList,
-	/// The ID of the initial authority set.
-	pub set_id: sp_finality_grandpa::SetId,
-	/// Should the pallet block transaction immediately after initialization.
-	pub is_halted: bool,
-}
-
 pub(crate) fn find_scheduled_change<H: HeaderT>(header: &H) -> Option<sp_finality_grandpa::ScheduledChange<H::Number>> {
 	use sp_runtime::generic::OpaqueDigestItemId;
 

modules/grandpa/src/lib.rs

@@ -10,6 +10,7 @@ license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
 parity-scale-codec = { version = "2.0.0", default-features = false, features = ["derive"] }
 
 # Bridge Dependencies
+bp-header-chain = { path = "../header-chain", default-features = false }
 bp-messages = { path = "../messages", default-features = false }
 bp-polkadot-core = { path = "../polkadot-core", default-features = false }
 bp-runtime = { path = "../runtime", default-features = false }
@@ -23,6 +24,7 @@ sp-version = { git = "https://github.com/paritytech/substrate", branch = "master
 [features]
 default = ["std"]
 std = [
+	"bp-header-chain/std",
 	"bp-messages/std",
 	"bp-polkadot-core/std",
 	"bp-runtime/std",

primitives/chain-rococo/Cargo.toml

@@ -21,6 +21,7 @@
 #![allow(clippy::unnecessary_mut_passed)]
 
 use bp_messages::{LaneId, MessageNonce, UnrewardedRelayersState, Weight};
+use bp_runtime::Chain;
 use sp_std::prelude::*;
 use sp_version::RuntimeVersion;
 
@@ -41,9 +42,33 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	transaction_version: 6,
 };
 
+/// Rococo Runtime `Call` enum.
+///
+/// The enum represents a subset of possible `Call`s we can send to Rococo chain.
+/// Ideally this code would be auto-generated from Metadata, because we want to
+/// avoid depending directly on the ENTIRE runtime just to get the encoding of `Dispatchable`s.
+///
+/// All entries here (like pretty much in the entire file) must be kept in sync with Rococo
+/// `construct_runtime`, so that we maintain SCALE-compatibility.
+///
+/// See: https://github.com/paritytech/polkadot/blob/master/runtime/rococo/src/lib.rs
 #[derive(parity_scale_codec::Encode, parity_scale_codec::Decode, Debug, PartialEq, Eq, Clone)]
 pub enum Call {
-	MockPallet,
+	/// Westend bridge pallet.
+	#[codec(index = 40)]
+	BridgeGrandpaWestend(BridgeGrandpaWestendCall),
+}
+
+#[derive(parity_scale_codec::Encode, parity_scale_codec::Decode, Debug, PartialEq, Eq, Clone)]
+#[allow(non_camel_case_types)]
+pub enum BridgeGrandpaWestendCall {
+	#[codec(index = 0)]
+	submit_finality_proof(
+		<PolkadotLike as Chain>::Header,
+		bp_header_chain::justification::GrandpaJustification<<PolkadotLike as Chain>::Header>,
+	),
+	#[codec(index = 1)]
+	initialize(bp_header_chain::InitializationData<<PolkadotLike as Chain>::Header>),
 }
 
 impl sp_runtime::traits::Dispatchable for Call {

primitives/chain-rococo/src/lib.rs

@@ -10,6 +10,7 @@ license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
 parity-scale-codec = { version = "2.0.0", default-features = false, features = ["derive"] }
 
 # Bridge Dependencies
+bp-header-chain = { path = "../header-chain", default-features = false }
 bp-messages = { path = "../messages", default-features = false }
 bp-polkadot-core = { path = "../polkadot-core", default-features = false }
 bp-runtime = { path = "../runtime", default-features = false }
@@ -23,6 +24,7 @@ sp-version = { git = "https://github.com/paritytech/substrate", branch = "master
 [features]
 default = ["std"]
 std = [
+	"bp-header-chain/std",
 	"bp-messages/std",
 	"bp-polkadot-core/std",
 	"bp-runtime/std",

primitives/chain-westend/Cargo.toml

@@ -21,6 +21,7 @@
 #![allow(clippy::unnecessary_mut_passed)]
 
 use bp_messages::{LaneId, MessageNonce, UnrewardedRelayersState, Weight};
+use bp_runtime::Chain;
 use sp_std::prelude::*;
 use sp_version::RuntimeVersion;
 
@@ -42,9 +43,33 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	transaction_version: 5,
 };
 
+/// Westend Runtime `Call` enum.
+///
+/// The enum represents a subset of possible `Call`s we can send to Westend chain.
+/// Ideally this code would be auto-generated from Metadata, because we want to
+/// avoid depending directly on the ENTIRE runtime just to get the encoding of `Dispatchable`s.
+///
+/// All entries here (like pretty much in the entire file) must be kept in sync with Westend
+/// `construct_runtime`, so that we maintain SCALE-compatibility.
+///
+/// See: https://github.com/paritytech/polkadot/blob/master/runtime/westend/src/lib.rs
 #[derive(parity_scale_codec::Encode, parity_scale_codec::Decode, Debug, PartialEq, Eq, Clone)]
 pub enum Call {
-	MockModule,
+	/// Rococo bridge pallet.
+	#[codec(index = 40)]
+	BridgeGrandpaRococo(BridgeGrandpaRococoCall),
+}
+
+#[derive(parity_scale_codec::Encode, parity_scale_codec::Decode, Debug, PartialEq, Eq, Clone)]
+#[allow(non_camel_case_types)]
+pub enum BridgeGrandpaRococoCall {
+	#[codec(index = 0)]
+	submit_finality_proof(
+		<PolkadotLike as Chain>::Header,
+		bp_header_chain::justification::GrandpaJustification<<PolkadotLike as Chain>::Header>,
+	),
+	#[codec(index = 1)]
+	initialize(bp_header_chain::InitializationData<<PolkadotLike as Chain>::Header>),
 }
 
 impl sp_runtime::traits::Dispatchable for Call {

primitives/chain-westend/src/lib.rs

@@ -55,6 +55,22 @@ impl AuthoritySet {
 	}
 }
 
+/// Data required for initializing the bridge pallet.
+///
+/// The bridge needs to know where to start its sync from, and this provides that initial context.
+#[derive(Default, Encode, Decode, RuntimeDebug, PartialEq, Eq, Clone)]
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
+pub struct InitializationData<H: HeaderT> {
+	/// The header from which we should start syncing.
+	pub header: H,
+	/// The initial authorities of the pallet.
+	pub authority_list: AuthorityList,
+	/// The ID of the initial authority set.
+	pub set_id: SetId,
+	/// Should the pallet block transaction immediately after initialization.
+	pub is_halted: bool,
+}
+
 /// base trait for verifying transaction inclusion proofs.
 pub trait InclusionProofVerifier {
 	/// Transaction type.

primitives/header-chain/src/lib.rs

@@ -26,6 +26,7 @@ bp-messages = { path = "../../primitives/messages" }
 bp-millau = { path = "../../primitives/chain-millau" }
 bp-polkadot = { path = "../../primitives/chain-polkadot" }
 bp-rialto = { path = "../../primitives/chain-rialto" }
+bp-rococo = { path = "../../primitives/chain-rococo" }
 bp-runtime = { path = "../../primitives/runtime" }
 bp-westend = { path = "../../primitives/chain-westend" }
 bridge-runtime-common = { path = "../../bin/runtime-common" }
@@ -35,12 +36,12 @@ headers-relay = { path = "../headers" }
 messages-relay = { path = "../messages" }
 millau-runtime = { path = "../../bin/millau/runtime" }
 pallet-bridge-dispatch = { path = "../../modules/dispatch" }
-pallet-bridge-grandpa = { path = "../../modules/grandpa" }
 pallet-bridge-messages = { path = "../../modules/messages" }
 relay-kusama-client = { path = "../client-kusama" }
 relay-millau-client = { path = "../client-millau" }
 relay-polkadot-client = { path = "../client-polkadot" }
 relay-rialto-client = { path = "../client-rialto" }
+relay-rococo-client = { path = "../client-rococo" }
 relay-substrate-client = { path = "../client-substrate" }
 relay-utils = { path = "../utils" }
 relay-westend-client = { path = "../client-westend" }

relays/bin-substrate/Cargo.toml

@@ -15,9 +15,9 @@
 // along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
 
 use crate::cli::{SourceConnectionParams, TargetConnectionParams, TargetSigningParams};
+use bp_header_chain::InitializationData;
 use bp_runtime::Chain as ChainBase;
 use codec::Encode;
-use pallet_bridge_grandpa::InitializationData;
 use relay_substrate_client::{Chain, TransactionSignScheme};
 use sp_core::{Bytes, Pair};
 use structopt::{clap::arg_enum, StructOpt};
@@ -44,6 +44,8 @@ arg_enum! {
 		MillauToRialto,
 		RialtoToMillau,
 		WestendToMillau,
+		WestendToRococo,
+		RococoToWestend,
 	}
 }
 
@@ -98,6 +100,30 @@ macro_rules! select_bridge {
 					.into()
 				}
 
+				$generic
+			}
+			InitBridgeName::WestendToRococo => {
+				type Source = relay_westend_client::Westend;
+				type Target = relay_rococo_client::Rococo;
+
+				fn encode_init_bridge(
+					init_data: InitializationData<<Source as ChainBase>::Header>,
+				) -> <Target as Chain>::Call {
+					bp_rococo::Call::BridgeGrandpaWestend(bp_rococo::BridgeGrandpaWestendCall::initialize(init_data))
+				}
+
+				$generic
+			}
+			InitBridgeName::RococoToWestend => {
+				type Source = relay_rococo_client::Rococo;
+				type Target = relay_westend_client::Westend;
+
+				fn encode_init_bridge(
+					init_data: InitializationData<<Source as ChainBase>::Header>,
+				) -> <Target as Chain>::Call {
+					bp_westend::Call::BridgeGrandpaRococo(bp_westend::BridgeGrandpaRococoCall::initialize(init_data))
+				}
+
 				$generic
 			}
 		}