Fetch Babe configuration from runtime state (#11760)

* Fetch babe config data from runtime state

* Some renaming

* More renaming

* Final nits

* Fix tests and benches

* Rename  to  in BabeConfiguration

* Remove duplicate babe parameter description

Already specified over the 'PRIMARY_PROBABILITY' constant value

* trigger pipeline

* trigger pipeline

substrate/bin/node/cli/src/service.rs

@@ -199,7 +199,7 @@ pub fn new_partial(
 	let justification_import = grandpa_block_import.clone();
 
 	let (block_import, babe_link) = sc_consensus_babe::block_import(
-		sc_consensus_babe::Config::get(&*client)?,
+		sc_consensus_babe::configuration(&*client)?,
 		grandpa_block_import,
 		client.clone(),
 	)?;
@@ -682,10 +682,7 @@ mod tests {
 						.epoch_changes()
 						.shared_data()
 						.epoch_data(&epoch_descriptor, |slot| {
-							sc_consensus_babe::Epoch::genesis(
-								babe_link.config().genesis_config(),
-								slot,
-							)
+							sc_consensus_babe::Epoch::genesis(babe_link.config(), slot)
 						})
 						.unwrap();
 

substrate/bin/node/rpc/src/lib.rs

@@ -36,7 +36,7 @@ use std::sync::Arc;
 use jsonrpsee::RpcModule;
 use node_primitives::{AccountId, Balance, Block, BlockNumber, Hash, Index};
 use sc_client_api::AuxStore;
-use sc_consensus_babe::{Config, Epoch};
+use sc_consensus_babe::{BabeConfiguration, Epoch};
 use sc_consensus_epochs::SharedEpochChanges;
 use sc_finality_grandpa::{
 	FinalityProofProvider, GrandpaJustificationStream, SharedAuthoritySet, SharedVoterState,
@@ -54,7 +54,7 @@ use sp_keystore::SyncCryptoStorePtr;
 /// Extra dependencies for BABE.
 pub struct BabeDeps {
 	/// BABE protocol config.
-	pub babe_config: Config,
+	pub babe_config: BabeConfiguration,
 	/// BABE pending epoch changes.
 	pub shared_epoch_changes: SharedEpochChanges<Block, Epoch>,
 	/// The keystore that manages the keys of the node.

substrate/bin/node/runtime/src/lib.rs

@@ -1859,19 +1859,15 @@ impl_runtime_apis! {
 	}
 
 	impl sp_consensus_babe::BabeApi<Block> for Runtime {
-		fn configuration() -> sp_consensus_babe::BabeGenesisConfiguration {
-			// The choice of `c` parameter (where `1 - c` represents the
-			// probability of a slot being empty), is done in accordance to the
-			// slot duration and expected target block time, for safely
-			// resisting network delays of maximum two seconds.
-			// <https://research.web3.foundation/en/latest/polkadot/BABE/Babe/#6-practical-results>
-			sp_consensus_babe::BabeGenesisConfiguration {
+		fn configuration() -> sp_consensus_babe::BabeConfiguration {
+			let epoch_config = Babe::epoch_config().unwrap_or(BABE_GENESIS_EPOCH_CONFIG);
+			sp_consensus_babe::BabeConfiguration {
 				slot_duration: Babe::slot_duration(),
 				epoch_length: EpochDuration::get(),
-				c: BABE_GENESIS_EPOCH_CONFIG.c,
-				genesis_authorities: Babe::authorities().to_vec(),
+				c: epoch_config.c,
+				authorities: Babe::authorities().to_vec(),
 				randomness: Babe::randomness(),
-				allowed_slots: BABE_GENESIS_EPOCH_CONFIG.allowed_slots,
+				allowed_slots: epoch_config.allowed_slots,
 			}
 		}
 

substrate/client/consensus/babe/rpc/src/lib.rs

@@ -25,7 +25,7 @@ use jsonrpsee::{
 	types::{error::CallError, ErrorObject},
 };
 
-use sc_consensus_babe::{authorship, Config, Epoch};
+use sc_consensus_babe::{authorship, Epoch};
 use sc_consensus_epochs::{descendent_query, Epoch as EpochT, SharedEpochChanges};
 use sc_rpc_api::DenyUnsafe;
 use serde::{Deserialize, Serialize};
@@ -33,7 +33,9 @@ use sp_api::{BlockId, ProvideRuntimeApi};
 use sp_application_crypto::AppKey;
 use sp_blockchain::{Error as BlockChainError, HeaderBackend, HeaderMetadata};
 use sp_consensus::{Error as ConsensusError, SelectChain};
-use sp_consensus_babe::{digests::PreDigest, AuthorityId, BabeApi as BabeRuntimeApi};
+use sp_consensus_babe::{
+	digests::PreDigest, AuthorityId, BabeApi as BabeRuntimeApi, BabeConfiguration,
+};
 use sp_core::crypto::ByteArray;
 use sp_keystore::{SyncCryptoStore, SyncCryptoStorePtr};
 use sp_runtime::traits::{Block as BlockT, Header as _};
@@ -57,7 +59,7 @@ pub struct Babe<B: BlockT, C, SC> {
 	/// shared reference to the Keystore
 	keystore: SyncCryptoStorePtr,
 	/// config (actually holds the slot duration)
-	babe_config: Config,
+	babe_config: BabeConfiguration,
 	/// The SelectChain strategy
 	select_chain: SC,
 	/// Whether to deny unsafe calls
@@ -70,7 +72,7 @@ impl<B: BlockT, C, SC> Babe<B, C, SC> {
 		client: Arc<C>,
 		shared_epoch_changes: SharedEpochChanges<B, Epoch>,
 		keystore: SyncCryptoStorePtr,
-		babe_config: Config,
+		babe_config: BabeConfiguration,
 		select_chain: SC,
 		deny_unsafe: DenyUnsafe,
 	) -> Self {
@@ -185,7 +187,7 @@ impl From<Error> for JsonRpseeError {
 async fn epoch_data<B, C, SC>(
 	epoch_changes: &SharedEpochChanges<B, Epoch>,
 	client: &Arc<C>,
-	babe_config: &Config,
+	babe_config: &BabeConfiguration,
 	slot: u64,
 	select_chain: &SC,
 ) -> Result<Epoch, Error>
@@ -202,7 +204,7 @@ where
 			&parent.hash(),
 			*parent.number(),
 			slot.into(),
-			|slot| Epoch::genesis(babe_config.genesis_config(), slot),
+			|slot| Epoch::genesis(babe_config, slot),
 		)
 		.map_err(|e| Error::Consensus(ConsensusError::ChainLookup(e.to_string())))?
 		.ok_or(Error::Consensus(ConsensusError::InvalidAuthoritiesSet))
@@ -221,7 +223,7 @@ mod tests {
 		TestClientBuilderExt,
 	};
 
-	use sc_consensus_babe::{block_import, AuthorityPair, Config};
+	use sc_consensus_babe::{block_import, AuthorityPair};
 	use std::sync::Arc;
 
 	/// creates keystore backed by a temp file
@@ -243,7 +245,7 @@ mod tests {
 		let builder = TestClientBuilder::new();
 		let (client, longest_chain) = builder.build_with_longest_chain();
 		let client = Arc::new(client);
-		let config = Config::get(&*client).expect("config available");
+		let config = sc_consensus_babe::configuration(&*client).expect("config available");
 		let (_, link) = block_import(config.clone(), client.clone(), client.clone())
 			.expect("can initialize block-import");
 

substrate/client/consensus/babe/src/aux_schema.rs

@@ -28,7 +28,7 @@ use sc_consensus_epochs::{
 	EpochChangesFor, SharedEpochChanges,
 };
 use sp_blockchain::{Error as ClientError, Result as ClientResult};
-use sp_consensus_babe::{BabeBlockWeight, BabeGenesisConfiguration};
+use sp_consensus_babe::{BabeBlockWeight, BabeConfiguration};
 use sp_runtime::traits::Block as BlockT;
 
 const BABE_EPOCH_CHANGES_VERSION: &[u8] = b"babe_epoch_changes_version";
@@ -57,7 +57,7 @@ where
 /// Load or initialize persistent epoch change data from backend.
 pub fn load_epoch_changes<Block: BlockT, B: AuxStore>(
 	backend: &B,
-	config: &BabeGenesisConfiguration,
+	config: &BabeConfiguration,
 ) -> ClientResult<SharedEpochChanges<Block, Epoch>> {
 	let version = load_decode::<_, u32>(backend, BABE_EPOCH_CHANGES_VERSION)?;
 
@@ -143,7 +143,7 @@ mod test {
 	use sc_consensus_epochs::{EpochHeader, PersistedEpoch, PersistedEpochHeader};
 	use sc_network_test::Block as TestBlock;
 	use sp_consensus::Error as ConsensusError;
-	use sp_consensus_babe::{AllowedSlots, BabeGenesisConfiguration};
+	use sp_consensus_babe::AllowedSlots;
 	use sp_core::H256;
 	use sp_runtime::traits::NumberFor;
 	use substrate_test_runtime_client;
@@ -182,11 +182,11 @@ mod test {
 
 		let epoch_changes = load_epoch_changes::<TestBlock, _>(
 			&client,
-			&BabeGenesisConfiguration {
+			&BabeConfiguration {
 				slot_duration: 10,
 				epoch_length: 4,
 				c: (3, 10),
-				genesis_authorities: Vec::new(),
+				authorities: Vec::new(),
 				randomness: Default::default(),
 				allowed_slots: AllowedSlots::PrimaryAndSecondaryPlainSlots,
 			},

substrate/client/consensus/babe/src/lib.rs

@@ -119,7 +119,7 @@ use sp_consensus::{
 	SelectChain,
 };
 use sp_consensus_babe::inherents::BabeInherentData;
-use sp_consensus_slots::{Slot, SlotDuration};
+use sp_consensus_slots::Slot;
 use sp_core::{crypto::ByteArray, ExecutionContext};
 use sp_inherents::{CreateInherentDataProviders, InherentData, InherentDataProvider};
 use sp_keystore::{SyncCryptoStore, SyncCryptoStorePtr};
@@ -137,8 +137,7 @@ pub use sp_consensus_babe::{
 		PrimaryPreDigest, SecondaryPlainPreDigest,
 	},
 	AuthorityId, AuthorityPair, AuthoritySignature, BabeApi, BabeAuthorityWeight, BabeBlockWeight,
-	BabeEpochConfiguration, BabeGenesisConfiguration, ConsensusLog, BABE_ENGINE_ID,
-	VRF_OUTPUT_LENGTH,
+	BabeConfiguration, BabeEpochConfiguration, ConsensusLog, BABE_ENGINE_ID, VRF_OUTPUT_LENGTH,
 };
 
 pub use aux_schema::load_block_weight as block_weight;
@@ -211,12 +210,12 @@ impl From<sp_consensus_babe::Epoch> for Epoch {
 impl Epoch {
 	/// Create the genesis epoch (epoch #0). This is defined to start at the slot of
 	/// the first block, so that has to be provided.
-	pub fn genesis(genesis_config: &BabeGenesisConfiguration, slot: Slot) -> Epoch {
+	pub fn genesis(genesis_config: &BabeConfiguration, slot: Slot) -> Epoch {
 		Epoch {
 			epoch_index: 0,
 			start_slot: slot,
 			duration: genesis_config.epoch_length,
-			authorities: genesis_config.genesis_authorities.clone(),
+			authorities: genesis_config.authorities.clone(),
 			randomness: genesis_config.randomness,
 			config: BabeEpochConfiguration {
 				c: genesis_config.c,
@@ -338,56 +337,36 @@ pub struct BabeIntermediate<B: BlockT> {
 /// Intermediate key for Babe engine.
 pub static INTERMEDIATE_KEY: &[u8] = b"babe1";
 
-/// Configuration for BABE used for defining block verification parameters as
-/// well as authoring (e.g. the slot duration).
-#[derive(Clone)]
-pub struct Config {
-	genesis_config: BabeGenesisConfiguration,
-}
+/// Read configuration from the runtime state at current best block.
+pub fn configuration<B: BlockT, C>(client: &C) -> ClientResult<BabeConfiguration>
+where
+	C: AuxStore + ProvideRuntimeApi<B> + UsageProvider<B>,
+	C::Api: BabeApi<B>,
+{
+	let block_id = if client.usage_info().chain.finalized_state.is_some() {
+		BlockId::Hash(client.usage_info().chain.best_hash)
+	} else {
+		debug!(target: "babe", "No finalized state is available. Reading config from genesis");
+		BlockId::Hash(client.usage_info().chain.genesis_hash)
+	};
 
-impl Config {
-	/// Create a new config by reading the genesis configuration from the runtime.
-	pub fn get<B: BlockT, C>(client: &C) -> ClientResult<Self>
-	where
-		C: AuxStore + ProvideRuntimeApi<B> + UsageProvider<B>,
-		C::Api: BabeApi<B>,
-	{
-		trace!(target: "babe", "Getting slot duration");
+	let runtime_api = client.runtime_api();
+	let version = runtime_api.api_version::<dyn BabeApi<B>>(&block_id)?;
 
-		let mut best_block_id = BlockId::Hash(client.usage_info().chain.best_hash);
-		if client.usage_info().chain.finalized_state.is_none() {
-			debug!(target: "babe", "No finalized state is available. Reading config from genesis");
-			best_block_id = BlockId::Hash(client.usage_info().chain.genesis_hash);
-		}
-		let runtime_api = client.runtime_api();
-
-		let version = runtime_api.api_version::<dyn BabeApi<B>>(&best_block_id)?;
-
-		let genesis_config = if version == Some(1) {
+	let config = match version {
+		Some(1) => {
 			#[allow(deprecated)]
 			{
-				runtime_api.configuration_before_version_2(&best_block_id)?.into()
+				runtime_api.configuration_before_version_2(&block_id)?.into()
 			}
-		} else if version == Some(2) {
-			runtime_api.configuration(&best_block_id)?
-		} else {
+		},
+		Some(2) => runtime_api.configuration(&block_id)?,
+		_ =>
 			return Err(sp_blockchain::Error::VersionInvalid(
 				"Unsupported or invalid BabeApi version".to_string(),
-			))
-		};
-
-		Ok(Config { genesis_config })
-	}
-
-	/// Get the genesis configuration.
-	pub fn genesis_config(&self) -> &BabeGenesisConfiguration {
-		&self.genesis_config
-	}
-
-	/// Get the slot duration defined in the genesis configuration.
-	pub fn slot_duration(&self) -> SlotDuration {
-		SlotDuration::from_millis(self.genesis_config.slot_duration)
-	}
+			)),
+	};
+	Ok(config)
 }
 
 /// Parameters for BABE.
@@ -611,7 +590,7 @@ fn aux_storage_cleanup<C: HeaderMetadata<Block> + HeaderBackend<Block>, Block: B
 
 async fn answer_requests<B: BlockT, C>(
 	mut request_rx: Receiver<BabeRequest<B>>,
-	config: Config,
+	config: BabeConfiguration,
 	client: Arc<C>,
 	epoch_changes: SharedEpochChanges<B, Epoch>,
 ) where
@@ -640,9 +619,7 @@ async fn answer_requests<B: BlockT, C>(
 						.ok_or(Error::<B>::FetchEpoch(parent_hash))?;
 
 					let viable_epoch = epoch_changes
-						.viable_epoch(&epoch_descriptor, |slot| {
-							Epoch::genesis(&config.genesis_config, slot)
-						})
+						.viable_epoch(&epoch_descriptor, |slot| Epoch::genesis(&config, slot))
 						.ok_or(Error::<B>::FetchEpoch(parent_hash))?;
 
 					Ok(sp_consensus_babe::Epoch {
@@ -739,7 +716,7 @@ struct BabeSlotWorker<B: BlockT, C, E, I, SO, L, BS> {
 	keystore: SyncCryptoStorePtr,
 	epoch_changes: SharedEpochChanges<B, Epoch>,
 	slot_notification_sinks: SlotNotificationSinks<B>,
-	config: Config,
+	config: BabeConfiguration,
 	block_proposal_slot_portion: SlotProportion,
 	max_block_proposal_slot_portion: Option<SlotProportion>,
 	telemetry: Option<TelemetryHandle>,
@@ -797,9 +774,7 @@ where
 	fn authorities_len(&self, epoch_descriptor: &Self::EpochData) -> Option<usize> {
 		self.epoch_changes
 			.shared_data()
-			.viable_epoch(epoch_descriptor, |slot| {
-				Epoch::genesis(&self.config.genesis_config, slot)
-			})
+			.viable_epoch(epoch_descriptor, |slot| Epoch::genesis(&self.config, slot))
 			.map(|epoch| epoch.as_ref().authorities.len())
 	}
 
@@ -814,9 +789,7 @@ where
 			slot,
 			self.epoch_changes
 				.shared_data()
-				.viable_epoch(epoch_descriptor, |slot| {
-					Epoch::genesis(&self.config.genesis_config, slot)
-				})?
+				.viable_epoch(epoch_descriptor, |slot| Epoch::genesis(&self.config, slot))?
 				.as_ref(),
 			&self.keystore,
 		);
@@ -1020,7 +993,7 @@ fn find_next_config_digest<B: BlockT>(
 #[derive(Clone)]
 pub struct BabeLink<Block: BlockT> {
 	epoch_changes: SharedEpochChanges<Block, Epoch>,
-	config: Config,
+	config: BabeConfiguration,
 }
 
 impl<Block: BlockT> BabeLink<Block> {
@@ -1030,7 +1003,7 @@ impl<Block: BlockT> BabeLink<Block> {
 	}
 
 	/// Get the config of this link.
-	pub fn config(&self) -> &Config {
+	pub fn config(&self) -> &BabeConfiguration {
 		&self.config
 	}
 }
@@ -1040,7 +1013,7 @@ pub struct BabeVerifier<Block: BlockT, Client, SelectChain, CAW, CIDP> {
 	client: Arc<Client>,
 	select_chain: SelectChain,
 	create_inherent_data_providers: CIDP,
-	config: Config,
+	config: BabeConfiguration,
 	epoch_changes: SharedEpochChanges<Block, Epoch>,
 	can_author_with: CAW,
 	telemetry: Option<TelemetryHandle>,
@@ -1245,9 +1218,7 @@ where
 				.map_err(|e| Error::<Block>::ForkTree(Box::new(e)))?
 				.ok_or(Error::<Block>::FetchEpoch(parent_hash))?;
 			let viable_epoch = epoch_changes
-				.viable_epoch(&epoch_descriptor, |slot| {
-					Epoch::genesis(&self.config.genesis_config, slot)
-				})
+				.viable_epoch(&epoch_descriptor, |slot| Epoch::genesis(&self.config, slot))
 				.ok_or(Error::<Block>::FetchEpoch(parent_hash))?;
 
 			// We add one to the current slot to allow for some small drift.
@@ -1353,7 +1324,7 @@ pub struct BabeBlockImport<Block: BlockT, Client, I> {
 	inner: I,
 	client: Arc<Client>,
 	epoch_changes: SharedEpochChanges<Block, Epoch>,
-	config: Config,
+	config: BabeConfiguration,
 }
 
 impl<Block: BlockT, I: Clone, Client> Clone for BabeBlockImport<Block, Client, I> {
@@ -1372,7 +1343,7 @@ impl<Block: BlockT, Client, I> BabeBlockImport<Block, Client, I> {
 		client: Arc<Client>,
 		epoch_changes: SharedEpochChanges<Block, Epoch>,
 		block_import: I,
-		config: Config,
+		config: BabeConfiguration,
 	) -> Self {
 		BabeBlockImport { client, inner: block_import, epoch_changes, config }
 	}
@@ -1580,9 +1551,7 @@ where
 				old_epoch_changes = Some((*epoch_changes).clone());
 
 				let viable_epoch = epoch_changes
-					.viable_epoch(&epoch_descriptor, |slot| {
-						Epoch::genesis(&self.config.genesis_config, slot)
-					})
+					.viable_epoch(&epoch_descriptor, |slot| Epoch::genesis(&self.config, slot))
 					.ok_or_else(|| {
 						ConsensusError::ClientImport(Error::<Block>::FetchEpoch(parent_hash).into())
 					})?;
@@ -1761,7 +1730,7 @@ where
 /// Also returns a link object used to correctly instantiate the import queue
 /// and background worker.
 pub fn block_import<Client, Block: BlockT, I>(
-	config: Config,
+	config: BabeConfiguration,
 	wrapped_block_import: I,
 	client: Arc<Client>,
 ) -> ClientResult<(BabeBlockImport<Block, Client, I>, BabeLink<Block>)>
@@ -1772,8 +1741,7 @@ where
 		+ PreCommitActions<Block>
 		+ 'static,
 {
-	let epoch_changes =
-		aux_schema::load_epoch_changes::<Block, _>(&*client, &config.genesis_config)?;
+	let epoch_changes = aux_schema::load_epoch_changes::<Block, _>(&*client, &config)?;
 	let link = BabeLink { epoch_changes: epoch_changes.clone(), config: config.clone() };
 
 	// NOTE: this isn't entirely necessary, but since we didn't use to prune the
@@ -1884,9 +1852,9 @@ where
 
 	// Revert epoch changes tree.
 
-	let config = Config::get(&*client)?;
-	let epoch_changes =
-		aux_schema::load_epoch_changes::<Block, Client>(&*client, config.genesis_config())?;
+	// This config is only used on-genesis.
+	let config = configuration(&*client)?;
+	let epoch_changes = aux_schema::load_epoch_changes::<Block, Client>(&*client, &config)?;
 	let mut epoch_changes = epoch_changes.shared_data();
 
 	if revert_up_to_number == Zero::zero() {

substrate/client/consensus/babe/src/migration.rs

@@ -17,7 +17,7 @@
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 use crate::{
-	AuthorityId, BabeAuthorityWeight, BabeEpochConfiguration, BabeGenesisConfiguration, Epoch,
+	AuthorityId, BabeAuthorityWeight, BabeConfiguration, BabeEpochConfiguration, Epoch,
 	NextEpochDescriptor, VRF_OUTPUT_LENGTH,
 };
 use codec::{Decode, Encode};
@@ -64,7 +64,7 @@ impl EpochT for EpochV0 {
 
 impl EpochV0 {
 	/// Migrate the sturct to current epoch version.
-	pub fn migrate(self, config: &BabeGenesisConfiguration) -> Epoch {
+	pub fn migrate(self, config: &BabeConfiguration) -> Epoch {
 		Epoch {
 			epoch_index: self.epoch_index,
 			start_slot: self.start_slot,

substrate/client/consensus/babe/src/tests.rs

@@ -36,6 +36,7 @@ use sp_consensus_babe::{
 	inherents::InherentDataProvider, make_transcript, make_transcript_data, AllowedSlots,
 	AuthorityPair, Slot,
 };
+use sp_consensus_slots::SlotDuration;
 use sp_core::crypto::Pair;
 use sp_keystore::{vrf::make_transcript as transcript_from_data, SyncCryptoStore};
 use sp_runtime::{
@@ -71,7 +72,7 @@ type BabeBlockImport =
 struct DummyFactory {
 	client: Arc<TestClient>,
 	epoch_changes: SharedEpochChanges<TestBlock, Epoch>,
-	config: Config,
+	config: BabeConfiguration,
 	mutator: Mutator,
 }
 
@@ -139,7 +140,7 @@ impl DummyProposer {
 				&self.parent_hash,
 				self.parent_number,
 				this_slot,
-				|slot| Epoch::genesis(self.factory.config.genesis_config(), slot),
+				|slot| Epoch::genesis(&self.factory.config, slot),
 			)
 			.expect("client has data to find epoch")
 			.expect("can compute epoch for baked block");
@@ -288,7 +289,7 @@ impl TestNetFactory for BabeTestNet {
 	) {
 		let client = client.as_client();
 
-		let config = Config::get(&*client).expect("config available");
+		let config = crate::configuration(&*client).expect("config available");
 		let (block_import, link) = crate::block_import(config, client.clone(), client.clone())
 			.expect("can initialize block-import");
 
@@ -559,11 +560,11 @@ fn can_author_block() {
 		},
 	};
 
-	let mut config = crate::BabeGenesisConfiguration {
+	let mut config = crate::BabeConfiguration {
 		slot_duration: 1000,
 		epoch_length: 100,
 		c: (3, 10),
-		genesis_authorities: Vec::new(),
+		authorities: Vec::new(),
 		randomness: [0; 32],
 		allowed_slots: AllowedSlots::PrimaryAndSecondaryPlainSlots,
 	};
@@ -708,12 +709,12 @@ fn importing_block_one_sets_genesis_epoch() {
 		&mut block_import,
 	);
 
-	let genesis_epoch = Epoch::genesis(data.link.config.genesis_config(), 999.into());
+	let genesis_epoch = Epoch::genesis(&data.link.config, 999.into());
 
 	let epoch_changes = data.link.epoch_changes.shared_data();
 	let epoch_for_second_block = epoch_changes
 		.epoch_data_for_child_of(descendent_query(&*client), &block_hash, 1, 1000.into(), |slot| {
-			Epoch::genesis(data.link.config.genesis_config(), slot)
+			Epoch::genesis(&data.link.config, slot)
 		})
 		.unwrap()
 		.unwrap();
@@ -771,16 +772,14 @@ fn revert_prunes_epoch_changes_and_removes_weights() {
 
 	// Load and check epoch changes.
 
-	let actual_nodes = aux_schema::load_epoch_changes::<Block, TestClient>(
-		&*client,
-		data.link.config.genesis_config(),
-	)
-	.expect("load epoch changes")
-	.shared_data()
-	.tree()
-	.iter()
-	.map(|(h, _, _)| *h)
-	.collect::<Vec<_>>();
+	let actual_nodes =
+		aux_schema::load_epoch_changes::<Block, TestClient>(&*client, &data.link.config)
+			.expect("load epoch changes")
+			.shared_data()
+			.tree()
+			.iter()
+			.map(|(h, _, _)| *h)
+			.collect::<Vec<_>>();
 
 	let expected_nodes = vec![
 		canon[0], // A

substrate/client/consensus/manual-seal/src/consensus.rs

@@ -39,7 +39,7 @@ pub trait ConsensusDataProvider<B: BlockT>: Send + Sync {
 	/// Attempt to create a consensus digest.
 	fn create_digest(&self, parent: &B::Header, inherents: &InherentData) -> Result<Digest, Error>;
 
-	/// set up the neccessary import params.
+	/// Set up the necessary import params.
 	fn append_block_import(
 		&self,
 		parent: &B::Header,

substrate/client/consensus/manual-seal/src/consensus/babe.rs

@@ -24,8 +24,7 @@ use crate::Error;
 use codec::Encode;
 use sc_client_api::{AuxStore, UsageProvider};
 use sc_consensus_babe::{
-	authorship, find_pre_digest, BabeIntermediate, CompatibleDigestItem, Config, Epoch,
-	INTERMEDIATE_KEY,
+	authorship, find_pre_digest, BabeIntermediate, CompatibleDigestItem, Epoch, INTERMEDIATE_KEY,
 };
 use sc_consensus_epochs::{
 	descendent_query, EpochHeader, SharedEpochChanges, ViableEpochDescriptor,
@@ -40,7 +39,7 @@ use sp_consensus::CacheKeyId;
 use sp_consensus_babe::{
 	digests::{NextEpochDescriptor, PreDigest, SecondaryPlainPreDigest},
 	inherents::BabeInherentData,
-	AuthorityId, BabeApi, BabeAuthorityWeight, ConsensusLog, BABE_ENGINE_ID,
+	AuthorityId, BabeApi, BabeAuthorityWeight, BabeConfiguration, ConsensusLog, BABE_ENGINE_ID,
 };
 use sp_consensus_slots::Slot;
 use sp_inherents::InherentData;
@@ -64,7 +63,10 @@ pub struct BabeConsensusDataProvider<B: BlockT, C, P> {
 	epoch_changes: SharedEpochChanges<B, Epoch>,
 
 	/// BABE config, gotten from the runtime.
-	config: Config,
+	/// NOTE: This is used to fetch `slot_duration` and `epoch_length` in the
+	/// `ConsensusDataProvider` implementation. Correct as far as these values
+	/// are not changed during an epoch change.
+	config: BabeConfiguration,
 
 	/// Authorities to be used for this babe chain.
 	authorities: Vec<(AuthorityId, BabeAuthorityWeight)>,
@@ -152,7 +154,7 @@ where
 			return Err(Error::StringError("Cannot supply empty authority set!".into()))
 		}
 
-		let config = Config::get(&*client)?;
+		let config = sc_consensus_babe::configuration(&*client)?;
 
 		Ok(Self {
 			config,
@@ -177,9 +179,7 @@ where
 			.ok_or(sp_consensus::Error::InvalidAuthoritiesSet)?;
 
 		let epoch = epoch_changes
-			.viable_epoch(&epoch_descriptor, |slot| {
-				Epoch::genesis(self.config.genesis_config(), slot)
-			})
+			.viable_epoch(&epoch_descriptor, |slot| Epoch::genesis(&self.config, slot))
 			.ok_or_else(|| {
 				log::info!(target: "babe", "create_digest: no viable_epoch :(");
 				sp_consensus::Error::InvalidAuthoritiesSet
@@ -306,7 +306,7 @@ where
 						identifier,
 						EpochHeader {
 							start_slot: slot,
-							end_slot: (*slot * self.config.genesis_config().epoch_length).into(),
+							end_slot: (*slot * self.config.epoch_length).into(),
 						},
 					),
 				_ => unreachable!(

substrate/client/consensus/manual-seal/src/consensus/timestamp.rs

@@ -63,7 +63,7 @@ impl SlotTimestampProvider {
 		C: AuxStore + HeaderBackend<B> + ProvideRuntimeApi<B> + UsageProvider<B>,
 		C::Api: BabeApi<B>,
 	{
-		let slot_duration = sc_consensus_babe::Config::get(&*client)?.slot_duration();
+		let slot_duration = sc_consensus_babe::configuration(&*client)?.slot_duration();
 
 		let time = Self::with_header(&client, slot_duration, |header| {
 			let slot_number = *sc_consensus_babe::find_pre_digest::<B>(&header)

substrate/frame/babe/src/lib.rs

@@ -306,6 +306,7 @@ pub mod pallet {
 	/// The configuration for the current epoch. Should never be `None` as it is initialized in
 	/// genesis.
 	#[pallet::storage]
+	#[pallet::getter(fn epoch_config)]
 	pub(super) type EpochConfig<T> = StorageValue<_, BabeEpochConfiguration>;
 
 	/// The configuration for the next epoch, `None` if the config will not change

substrate/primitives/consensus/babe/src/lib.rs

@@ -137,7 +137,7 @@ pub enum ConsensusLog {
 
 /// Configuration data used by the BABE consensus engine.
 #[derive(Clone, PartialEq, Eq, Encode, Decode, RuntimeDebug)]
-pub struct BabeGenesisConfigurationV1 {
+pub struct BabeConfigurationV1 {
 	/// The slot duration in milliseconds for BABE. Currently, only
 	/// the value provided by this type at genesis will be used.
 	///
@@ -156,7 +156,7 @@ pub struct BabeGenesisConfigurationV1 {
 	pub c: (u64, u64),
 
 	/// The authorities for the genesis epoch.
-	pub genesis_authorities: Vec<(AuthorityId, BabeAuthorityWeight)>,
+	pub authorities: Vec<(AuthorityId, BabeAuthorityWeight)>,
 
 	/// The randomness for the genesis epoch.
 	pub randomness: Randomness,
@@ -166,13 +166,13 @@ pub struct BabeGenesisConfigurationV1 {
 	pub secondary_slots: bool,
 }
 
-impl From<BabeGenesisConfigurationV1> for BabeGenesisConfiguration {
-	fn from(v1: BabeGenesisConfigurationV1) -> Self {
+impl From<BabeConfigurationV1> for BabeConfiguration {
+	fn from(v1: BabeConfigurationV1) -> Self {
 		Self {
 			slot_duration: v1.slot_duration,
 			epoch_length: v1.epoch_length,
 			c: v1.c,
-			genesis_authorities: v1.genesis_authorities,
+			authorities: v1.authorities,
 			randomness: v1.randomness,
 			allowed_slots: if v1.secondary_slots {
 				AllowedSlots::PrimaryAndSecondaryPlainSlots
@@ -185,7 +185,7 @@ impl From<BabeGenesisConfigurationV1> for BabeGenesisConfiguration {
 
 /// Configuration data used by the BABE consensus engine.
 #[derive(Clone, PartialEq, Eq, Encode, Decode, RuntimeDebug)]
-pub struct BabeGenesisConfiguration {
+pub struct BabeConfiguration {
 	/// The slot duration in milliseconds for BABE. Currently, only
 	/// the value provided by this type at genesis will be used.
 	///
@@ -203,16 +203,23 @@ pub struct BabeGenesisConfiguration {
 	/// of a slot being empty.
 	pub c: (u64, u64),
 
-	/// The authorities for the genesis epoch.
-	pub genesis_authorities: Vec<(AuthorityId, BabeAuthorityWeight)>,
+	/// The authorities
+	pub authorities: Vec<(AuthorityId, BabeAuthorityWeight)>,
 
-	/// The randomness for the genesis epoch.
+	/// The randomness
 	pub randomness: Randomness,
 
 	/// Type of allowed slots.
 	pub allowed_slots: AllowedSlots,
 }
 
+impl BabeConfiguration {
+	/// Convenience method to get the slot duration as a `SlotDuration` value.
+	pub fn slot_duration(&self) -> SlotDuration {
+		SlotDuration::from_millis(self.slot_duration)
+	}
+}
+
 /// Types of allowed slots.
 #[derive(Clone, Copy, PartialEq, Eq, Encode, Decode, RuntimeDebug, MaxEncodedLen, TypeInfo)]
 #[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
@@ -237,7 +244,7 @@ impl AllowedSlots {
 	}
 }
 
-/// Configuration data used by the BABE consensus engine.
+/// Configuration data used by the BABE consensus engine that may change with epochs.
 #[derive(Clone, PartialEq, Eq, Encode, Decode, RuntimeDebug, MaxEncodedLen, TypeInfo)]
 #[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
 pub struct BabeEpochConfiguration {
@@ -357,12 +364,12 @@ sp_api::decl_runtime_apis! {
 	/// API necessary for block authorship with BABE.
 	#[api_version(2)]
 	pub trait BabeApi {
-		/// Return the genesis configuration for BABE. The configuration is only read on genesis.
-		fn configuration() -> BabeGenesisConfiguration;
+		/// Return the configuration for BABE.
+		fn configuration() -> BabeConfiguration;
 
 		/// Return the configuration for BABE. Version 1.
 		#[changed_in(2)]
-		fn configuration() -> BabeGenesisConfigurationV1;
+		fn configuration() -> BabeConfigurationV1;
 
 		/// Returns the slot that started the current epoch.
 		fn current_epoch_start() -> Slot;

substrate/test-utils/runtime/src/lib.rs

@@ -849,12 +849,12 @@ cfg_if! {
 			}
 
 			impl sp_consensus_babe::BabeApi<Block> for Runtime {
-				fn configuration() -> sp_consensus_babe::BabeGenesisConfiguration {
-					sp_consensus_babe::BabeGenesisConfiguration {
+				fn configuration() -> sp_consensus_babe::BabeConfiguration {
+					sp_consensus_babe::BabeConfiguration {
 						slot_duration: 1000,
 						epoch_length: EpochDuration::get(),
 						c: (3, 10),
-						genesis_authorities: system::authorities()
+						authorities: system::authorities()
 							.into_iter().map(|x|(x, 1)).collect(),
 						randomness: <pallet_babe::Pallet<Runtime>>::randomness(),
 						allowed_slots: AllowedSlots::PrimaryAndSecondaryPlainSlots,
@@ -1123,12 +1123,12 @@ cfg_if! {
 			}
 
 			impl sp_consensus_babe::BabeApi<Block> for Runtime {
-				fn configuration() -> sp_consensus_babe::BabeGenesisConfiguration {
-					sp_consensus_babe::BabeGenesisConfiguration {
+				fn configuration() -> sp_consensus_babe::BabeConfiguration {
+					sp_consensus_babe::BabeConfiguration {
 						slot_duration: 1000,
 						epoch_length: EpochDuration::get(),
 						c: (3, 10),
-						genesis_authorities: system::authorities()
+						authorities: system::authorities()
 							.into_iter().map(|x|(x, 1)).collect(),
 						randomness: <pallet_babe::Pallet<Runtime>>::randomness(),
 						allowed_slots: AllowedSlots::PrimaryAndSecondaryPlainSlots,