Westend<>Rococo Headers Relay (#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>

bridges/relays/bin-substrate/src/cli/init_bridge.rs

@@ -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
 			}
 		}

bridges/relays/bin-substrate/src/cli/mod.rs

@@ -373,6 +373,7 @@ macro_rules! declare_chain_options {
 				/// Parse signing params into chain-specific KeyPair.
 				pub fn to_keypair<Chain: CliChain>(&self) -> anyhow::Result<Chain::KeyPair> {
 					use sp_core::crypto::Pair;
+
 					Chain::KeyPair::from_string(
 						&self.[<$chain_prefix _signer>],
 						self.[<$chain_prefix _signer_password>].as_deref()

bridges/relays/bin-substrate/src/cli/relay_headers.rs

@@ -42,6 +42,8 @@ arg_enum! {
 		MillauToRialto,
 		RialtoToMillau,
 		WestendToMillau,
+		WestendToRococo,
+		RococoToWestend,
 	}
 }
 
@@ -67,6 +69,20 @@ macro_rules! select_bridge {
 				type Target = relay_millau_client::Millau;
 				type Finality = crate::rialto_millau::westend_headers_to_millau::WestendFinalityToMillau;
 
+				$generic
+			}
+			RelayHeadersBridge::WestendToRococo => {
+				type Source = relay_westend_client::Westend;
+				type Target = relay_rococo_client::Rococo;
+				type Finality = crate::rialto_millau::westend_headers_to_rococo::WestendFinalityToRococo;
+
+				$generic
+			}
+			RelayHeadersBridge::RococoToWestend => {
+				type Source = relay_rococo_client::Rococo;
+				type Target = relay_westend_client::Westend;
+				type Finality = crate::rialto_millau::rococo_headers_to_westend::RococoFinalityToWestend;
+
 				$generic
 			}
 		}