Enable Babe RPC for getting epoch authorship (#1065)

Enable babe_epochAuthorship that was added in substrate#4729 for
querying information about slots that can be claimed in the current
epoch.

polkadot/Cargo.lock

@@ -4276,11 +4276,17 @@ dependencies = [
  "parity-scale-codec",
  "polkadot-primitives",
  "sc-client-api",
+ "sc-consensus-babe",
+ "sc-consensus-babe-rpc",
+ "sc-consensus-epochs",
  "sc-finality-grandpa",
  "sc-finality-grandpa-rpc",
+ "sc-keystore",
  "sc-rpc",
  "sp-api",
  "sp-blockchain",
+ "sp-consensus",
+ "sp-consensus-babe",
  "sp-runtime",
  "sp-transaction-pool",
  "substrate-frame-rpc-system",
@@ -5536,6 +5542,28 @@ dependencies = [
  "substrate-prometheus-endpoint",
 ]
 
+[[package]]
+name = "sc-consensus-babe-rpc"
+version = "0.8.0-dev"
+source = "git+https://github.com/paritytech/substrate#c0ccc24d02080ab4fbb2c65440327fc72acb6c42"
+dependencies = [
+ "derive_more 0.99.5",
+ "futures 0.3.4",
+ "jsonrpc-core",
+ "jsonrpc-core-client",
+ "jsonrpc-derive",
+ "sc-consensus-babe",
+ "sc-consensus-epochs",
+ "sc-keystore",
+ "serde",
+ "sp-api",
+ "sp-blockchain",
+ "sp-consensus",
+ "sp-consensus-babe",
+ "sp-core",
+ "sp-runtime",
+]
+
 [[package]]
 name = "sc-consensus-epochs"
 version = "0.8.0-alpha.8"

polkadot/rpc/Cargo.toml

@@ -11,9 +11,15 @@ sc-client-api = { git = "https://github.com/paritytech/substrate", branch = "mas
 sp-blockchain = { git = "https://github.com/paritytech/substrate", branch = "master"  }
 sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master"  }
 sp-api = { git = "https://github.com/paritytech/substrate", branch = "master"  }
+sp-consensus = { git = "https://github.com/paritytech/substrate", branch = "master"  }
+sp-consensus-babe = { git = "https://github.com/paritytech/substrate", branch = "master"  }
 sc-rpc = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sc-consensus-babe = { git = "https://github.com/paritytech/substrate", branch = "master"}
+sc-consensus-babe-rpc = { git = "https://github.com/paritytech/substrate", branch = "master"}
+sc-consensus-epochs = { git = "https://github.com/paritytech/substrate", branch = "master"}
 sc-finality-grandpa = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sc-finality-grandpa-rpc = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sc-keystore = { git = "https://github.com/paritytech/substrate", branch = "master"}
 txpool-api = { package = "sp-transaction-pool", git = "https://github.com/paritytech/substrate", branch = "master" }
 frame-rpc-system = { package = "substrate-frame-rpc-system", git = "https://github.com/paritytech/substrate", branch = "master"  }
 pallet-transaction-payment-rpc = { git = "https://github.com/paritytech/substrate", branch = "master" }

polkadot/rpc/src/lib.rs

@@ -23,12 +23,37 @@ use std::sync::Arc;
 use polkadot_primitives::{Block, BlockNumber, AccountId, Nonce, Balance, Hash};
 use sp_api::ProvideRuntimeApi;
 use txpool_api::TransactionPool;
-use sp_blockchain::HeaderBackend;
+use sp_blockchain::{HeaderBackend, HeaderMetadata, Error as BlockChainError};
+use sp_consensus::SelectChain;
 use sc_client_api::light::{Fetcher, RemoteBlockchain};
+use sc_consensus_babe::Epoch;
+use sp_consensus_babe::BabeApi;
 
 /// A type representing all RPC extensions.
 pub type RpcExtension = jsonrpc_core::IoHandler<sc_rpc::Metadata>;
 
+/// Light client extra dependencies.
+pub struct LightDeps<C, F, P> {
+	/// The client instance to use.
+	pub client: Arc<C>,
+	/// Transaction pool instance.
+	pub pool: Arc<P>,
+	/// Remote access to the blockchain (async).
+	pub remote_blockchain: Arc<dyn RemoteBlockchain<Block>>,
+	/// Fetcher instance.
+	pub fetcher: Arc<F>,
+}
+
+/// Extra dependencies for BABE.
+pub struct BabeDeps {
+	/// BABE protocol config.
+	pub babe_config: sc_consensus_babe::Config,
+	/// BABE pending epoch changes.
+	pub shared_epoch_changes: sc_consensus_epochs::SharedEpochChanges<Block, Epoch>,
+	/// The keystore that manages the keys of the node.
+	pub keystore: sc_keystore::KeyStorePtr,
+}
+
 /// Dependencies for GRANDPA
 pub struct GrandpaDeps {
 	/// Voting round info.
@@ -37,31 +62,65 @@ pub struct GrandpaDeps {
 	pub shared_authority_set: sc_finality_grandpa::SharedAuthoritySet<Hash, BlockNumber>,
 }
 
+/// Full client dependencies
+pub struct FullDeps<C, P, SC> {
+	/// The client instance to use.
+	pub client: Arc<C>,
+	/// Transaction pool instance.
+	pub pool: Arc<P>,
+	/// The SelectChain Strategy
+	pub select_chain: SC,
+	/// BABE specific dependencies.
+	pub babe: BabeDeps,
+	/// GRANDPA specific dependencies.
+	pub grandpa: GrandpaDeps,
+}
+
 /// Instantiate all RPC extensions.
-pub fn create_full<C, P, UE>(client: Arc<C>, pool: Arc<P>, grandpa_deps: GrandpaDeps) -> RpcExtension where
+pub fn create_full<C, P, UE, SC>(deps: FullDeps<C, P, SC>) -> RpcExtension where
 	C: ProvideRuntimeApi<Block>,
-	C: HeaderBackend<Block>,
+	C: HeaderBackend<Block> + HeaderMetadata<Block, Error=BlockChainError>,
 	C: Send + Sync + 'static,
 	C::Api: frame_rpc_system::AccountNonceApi<Block, AccountId, Nonce>,
 	C::Api: pallet_transaction_payment_rpc::TransactionPaymentRuntimeApi<Block, Balance, UE>,
+	C::Api: BabeApi<Block>,
 	P: TransactionPool + Sync + Send + 'static,
 	UE: codec::Codec + Send + Sync + 'static,
+	SC: SelectChain<Block> + 'static,
 {
 	use frame_rpc_system::{FullSystem, SystemApi};
 	use pallet_transaction_payment_rpc::{TransactionPayment, TransactionPaymentApi};
 	use sc_finality_grandpa_rpc::{GrandpaApi, GrandpaRpcHandler};
+	use sc_consensus_babe_rpc::BabeRPCHandler;
 
 	let mut io = jsonrpc_core::IoHandler::default();
+	let FullDeps {
+		client,
+		pool,
+		select_chain,
+		babe,
+		grandpa,
+	} = deps;
+	let BabeDeps {
+		keystore,
+		babe_config,
+		shared_epoch_changes,
+	} = babe;
 	let GrandpaDeps {
 		shared_voter_state,
 		shared_authority_set,
-	} = grandpa_deps;
+	} = grandpa;
 
 	io.extend_with(
 		SystemApi::to_delegate(FullSystem::new(client.clone(), pool))
 	);
 	io.extend_with(
-		TransactionPaymentApi::to_delegate(TransactionPayment::new(client))
+		TransactionPaymentApi::to_delegate(TransactionPayment::new(client.clone()))
+	);
+	io.extend_with(
+		sc_consensus_babe_rpc::BabeApi::to_delegate(
+			BabeRPCHandler::new(client, shared_epoch_changes, keystore, babe_config, select_chain)
+		)
 	);
 	io.extend_with(
 		GrandpaApi::to_delegate(GrandpaRpcHandler::new(
@@ -73,12 +132,7 @@ pub fn create_full<C, P, UE>(client: Arc<C>, pool: Arc<P>, grandpa_deps: Grandpa
 }
 
 /// Instantiate all RPC extensions for light node.
-pub fn create_light<C, P, F, UE>(
+pub fn create_light<C, P, F, UE>(deps: LightDeps<C, F, P>) -> RpcExtension
-	client: Arc<C>,
-	remote_blockchain: Arc<dyn RemoteBlockchain<Block>>,
-	fetcher: Arc<F>,
-	pool: Arc<P>,
-) -> RpcExtension
 	where
 		C: ProvideRuntimeApi<Block>,
 		C: HeaderBackend<Block>,
@@ -91,6 +145,12 @@ pub fn create_light<C, P, F, UE>(
 {
 	use frame_rpc_system::{LightSystem, SystemApi};
 
+	let LightDeps {
+		client,
+		pool,
+		remote_blockchain,
+		fetcher,
+	} = deps;
 	let mut io = jsonrpc_core::IoHandler::default();
 	io.extend_with(
 		SystemApi::<AccountId, Nonce>::to_delegate(LightSystem::new(client, remote_blockchain, fetcher, pool))

polkadot/service/src/lib.rs

@@ -214,16 +214,29 @@ macro_rules! new_full_start {
 				Ok(import_queue)
 			})?
 			.with_rpc_extensions(|builder| -> Result<polkadot_rpc::RpcExtension, _> {
+				let babe_link = import_setup.as_ref().map(|s| &s.2)
+					.expect("BabeLink is present for full services or set up faile; qed.");
 				let grandpa_link = import_setup.as_ref().map(|s| &s.1)
 					.expect("GRANDPA LinkHalf is present for full services or set up failed; qed.");
 				let shared_authority_set = grandpa_link.shared_authority_set();
 				let shared_voter_state = SharedVoterState::empty();
-				let grandpa_deps = polkadot_rpc::GrandpaDeps {
+				let deps = polkadot_rpc::FullDeps {
-					shared_voter_state: shared_voter_state.clone(),
+					client: builder.client().clone(),
-					shared_authority_set: shared_authority_set.clone(),
+					pool: builder.pool(),
+					select_chain: builder.select_chain().cloned()
+						.expect("SelectChain is present for full services or set up failed; qed."),
+					babe: polkadot_rpc::BabeDeps {
+						keystore: builder.keystore(),
+						babe_config: babe::BabeLink::config(babe_link).clone(),
+						shared_epoch_changes: babe::BabeLink::epoch_changes(babe_link).clone(),
+					},
+					grandpa: polkadot_rpc::GrandpaDeps {
+						shared_voter_state: shared_voter_state.clone(),
+						shared_authority_set: shared_authority_set.clone(),
+					},
 				};
 				rpc_setup = Some((shared_voter_state));
-				Ok(polkadot_rpc::create_full(builder.client().clone(), builder.pool(), grandpa_deps))
+				Ok(polkadot_rpc::create_full(deps))
 			})?;
 
 		(builder, import_setup, inherent_data_providers, rpc_setup)
@@ -586,7 +599,13 @@ macro_rules! new_light {
 				let remote_blockchain = builder.remote_backend()
 					.ok_or_else(|| "Trying to start node RPC without active remote blockchain")?;
 
-				Ok(polkadot_rpc::create_light(builder.client().clone(), remote_blockchain, fetcher, builder.pool()))
+				let light_deps = polkadot_rpc::LightDeps {
+					remote_blockchain,
+					fetcher,
+					client: builder.client().clone(),
+					pool: builder.pool(),
+				};
+				Ok(polkadot_rpc::create_light(light_deps))
 			})?
 			.build()
 	}}