Add basic BABE consensus type (#2165)

* Add basic BABE consensus type * Update core/consensus/babe/slots/Cargo.toml Co-Authored-By: DemiMarie-parity <48690212+DemiMarie-parity@users.noreply.github.com> * Fix parameterization and run `rustfmt` * Respond to review comments * Update various Cargo.lock files * Revert "Update various Cargo.lock files" This reverts commit af53d7624752a744320e9cbb25749fdd8e6f46d2. * `BabeSealSignature` → `BabeSeal` * Move slot code to its own crate This was highly non-trivial, due to cyclic dependencies. * Remove redundancy between AuRa and BABE Some of the code duplication was removed using a macro. * Fix build error * Avoid non-`#[doc(hidden)]` re-exports Also, bump some library versions in `Cargo.toml`. * Remove dead code in AuRa * Remove impl_slot macro It was more trouble than it was worth. Also, delete useless dependencies on Serde. * AuRa and BABE need different DB keys * Bring back `aura::Network`, but deprecate it. * Improve docs and add `slot_duration` inherent method * Add docs to `substrate_consensus_aura::SlotDuration` * Add missing documentation and #![forbid(missing_docs, unsafe_code)] * Add a #![forbid(missing_docs)] * Remove dependency of `test-runtime` on `slots` * Update core/consensus/babe/src/lib.rs Co-Authored-By: DemiMarie-parity <48690212+DemiMarie-parity@users.noreply.github.com> * Remove wrongly added file * Fix copyright notice Co-Authored-By: DemiMarie-parity <48690212+DemiMarie-parity@users.noreply.github.com> * Bump `impl_version` and `spec_version` * Fix deprecation version; remove spurious carets * Update Cargo.lock * Update dependencies
2026-06-09 20:11:09 +00:00 · 2019-04-15 01:41:07 -04:00
parent 72a1c6298e
commit ae916c6c5e
20 changed files with 1242 additions and 841 deletions
@@ -25,7 +25,9 @@ members = [
 	"core/client/db",
 	"core/consensus/common",
 	"core/consensus/aura",
+	"core/consensus/babe",
 	"core/consensus/rhd",
+	"core/consensus/slots",
 	"core/executor",
 	"core/finality-grandpa",
 	"core/finality-grandpa/primitives",
@@ -1,23 +1,22 @@
 [package]
 name = "substrate-consensus-aura"
-version = "1.0.0"
+version = "1.0.1"
 authors = ["Parity Technologies <admin@parity.io>"]
 description = "Aura consensus algorithm for substrate"
 edition = "2018"

 [dependencies]
-parity-codec = "3.3"
-client = { package = "substrate-client", path = "../../client" }
+parity-codec = "3.4"
 primitives = { package = "substrate-primitives", path = "../../primitives" }
 runtime_support = { package = "srml-support", path = "../../../srml/support" }
-runtime_primitives = { package = "sr-primitives", path = "../../sr-primitives" }
 runtime_version = { package = "sr-version", path = "../../sr-version" }
 runtime_io = { package = "sr-io", path = "../../sr-io" }
-aura_slots = { package = "substrate-consensus-aura-slots", path = "slots" }
+slots = { package = "substrate-consensus-slots", path = "../slots" }
 aura_primitives = { package = "substrate-consensus-aura-primitives", path = "primitives" }
 inherents = { package = "substrate-inherents", path = "../../inherents" }
 srml-consensus = { path = "../../../srml/consensus" }
 srml-aura = { path = "../../../srml/aura" }
+client = { package = "substrate-client", path = "../../client" }
 substrate-telemetry = { path = "../../telemetry" }
 futures = "0.1.17"
 tokio = "0.1.7"
@@ -26,6 +25,7 @@ error-chain = "0.12"
 log = "0.4"
 consensus_common = { package = "substrate-consensus-common", path = "../common" }
 authorities = { package = "substrate-consensus-authorities", path = "../authorities" }
+runtime_primitives = { package = "sr-primitives", path = "../../sr-primitives" }

 [dev-dependencies]
 keyring = { package = "substrate-keyring", path = "../../keyring" }
@@ -25,7 +25,8 @@
 //!
 //! Blocks from future steps will be either deferred or rejected depending on how
 //! far in the future they are.
-#![deny(deprecated)]
+#![deny(warnings)]
+#![forbid(missing_docs, unsafe_code)]
 use std::{sync::Arc, time::Duration, thread, marker::PhantomData, hash::Hash, fmt::Debug};

 use parity_codec::{Encode, Decode};
@@ -34,10 +35,14 @@ use consensus_common::{self, Authorities, BlockImport, Environment, Proposer,
 };
 use consensus_common::well_known_cache_keys;
 use consensus_common::import_queue::{Verifier, BasicQueue, SharedBlockImport, SharedJustificationImport};
-use client::ChainHead;
-use client::block_builder::api::BlockBuilder as BlockBuilderApi;
-use client::blockchain::ProvideCache;
-use client::runtime_api::{ApiExt, Core as CoreApi};
+use client::{
+	ChainHead,
+	block_builder::api::BlockBuilder as BlockBuilderApi,
+	blockchain::ProvideCache,
+	runtime_api::{ApiExt, Core as CoreApi},
+	error::Result as CResult,
+	backend::AuxStore,
+};
 use aura_primitives::AURA_ENGINE_ID;
 use runtime_primitives::{generic, generic::BlockId, Justification};
 use runtime_primitives::traits::{
@@ -47,7 +52,7 @@ use primitives::Pair;
 use inherents::{InherentDataProviders, InherentData, RuntimeString};
 use authorities::AuthoritiesApi;

-use futures::{Stream, Future, IntoFuture, future};
+use futures::{Future, IntoFuture, future, stream::Stream};
 use tokio::timer::Timeout;
 use log::{warn, debug, info, trace};

@@ -57,9 +62,8 @@ use srml_aura::{
 };
 use substrate_telemetry::{telemetry, CONSENSUS_TRACE, CONSENSUS_DEBUG, CONSENSUS_WARN, CONSENSUS_INFO};

-use aura_slots::{CheckedHeader, SlotWorker, SlotInfo, SlotCompatible};
+use slots::{CheckedHeader, SlotWorker, SlotInfo, SlotCompatible};

-pub use aura_slots::SlotDuration;
 pub use aura_primitives::*;
 pub use consensus_common::SyncOracle;

@@ -70,6 +74,10 @@ type Signature<P> = <P as Pair>::Signature;
 /// handle to a gossip service or similar.
 ///
 /// Intended to be a lightweight handle such as an `Arc`.
+#[deprecated(
+	since = "1.0.1",
+	note = "This is dead code and will be removed in a future release",
+)]
 pub trait Network: Clone {
 	/// A stream of input messages for a topic.
 	type In: Stream<Item=Vec<u8>,Error=()>;
@@ -78,6 +86,25 @@ pub trait Network: Clone {
 	fn send_message(&self, slot: u64, message: Vec<u8>);
 }

+/// A slot duration. Create with `get_or_compute`.
+pub struct SlotDuration(slots::SlotDuration<u64>);
+
+impl SlotDuration {
+	/// Either fetch the slot duration from disk or compute it from the genesis
+	/// state.
+	pub fn get_or_compute<B: Block, C>(client: &C) -> CResult<Self>
+	where
+		C: AuxStore, C: ProvideRuntimeApi, C::Api: AuraApi<B>,
+	{
+		slots::SlotDuration::get_or_compute(client, |a, b| a.slot_duration(b)).map(Self)
+	}
+
+	/// Get the slot duration in milliseconds.
+	pub fn get(&self) -> u64 {
+		self.0.get()
+	}
+}
+
 /// Get slot author for given block along with authorities.
 fn slot_author<P: Pair>(slot_num: u64, authorities: &[AuthorityId<P>]) -> Option<&AuthorityId<P>> {
 	if authorities.is_empty() { return None }
@@ -153,6 +180,7 @@ impl<P, Hash> CompatibleDigestItem<P> for generic::DigestItem<Hash, P::Public, P
 	}
 }

+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 struct AuraSlotCompatible;

 impl SlotCompatible for AuraSlotCompatible {
@@ -203,8 +231,8 @@ pub fn start_aura_thread<B, C, E, I, P, SO, Error, OnExit>(
 		force_authoring,
 	};

-	aura_slots::start_slot_worker_thread::<_, _, _, _, AuraSlotCompatible, _>(
-		slot_duration,
+	slots::start_slot_worker_thread::<_, _, _, _, AuraSlotCompatible, u64, _>(
+		slot_duration.0,
 		client,
 		Arc::new(worker),
 		sync_oracle,
@@ -249,8 +277,8 @@ pub fn start_aura<B, C, E, I, P, SO, Error, OnExit>(
 		sync_oracle: sync_oracle.clone(),
 		force_authoring,
 	};
-	aura_slots::start_slot_worker::<_, _, _, _, AuraSlotCompatible, _>(
-		slot_duration,
+	slots::start_slot_worker::<_, _, _, _, _, AuraSlotCompatible, _>(
+		slot_duration.0,
 		client,
 		Arc::new(worker),
 		sync_oracle,
@@ -803,9 +831,9 @@ mod tests {
 	use client::BlockchainEvents;
 	use test_client;

-	type Error = ::client::error::Error;
+	type Error = client::error::Error;

-	type TestClient = ::client::Client<test_client::Backend, test_client::Executor, TestBlock, test_client::runtime::RuntimeApi>;
+	type TestClient = client::Client<test_client::Backend, test_client::Executor, TestBlock, test_client::runtime::RuntimeApi>;

 	struct DummyFactory(Arc<TestClient>);
 	struct DummyProposer(u64, Arc<TestClient>);
@@ -0,0 +1,40 @@
+[package]
+name = "substrate-consensus-babe"
+version = "1.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+description = "BABE consensus algorithm for substrate"
+edition = "2018"
+
+[dependencies]
+parity-codec = "3.4.0"
+parity-codec-derive = "3.3.0"
+babe_primitives = { package = "substrate-consensus-babe-primitives", path = "primitives" }
+primitives = { package = "substrate-primitives", path = "../../primitives" }
+runtime_support = { package = "srml-support", path = "../../../srml/support" }
+runtime_version = { package = "sr-version", path = "../../sr-version" }
+runtime_io = { package = "sr-io", path = "../../sr-io" }
+inherents = { package = "substrate-inherents", path = "../../inherents" }
+srml-consensus = { path = "../../../srml/consensus" }
+substrate-telemetry = { path = "../../telemetry" }
+client = { package = "substrate-client", path = "../../client" }
+consensus_common = { package = "substrate-consensus-common", path = "../common" }
+authorities = { package = "substrate-consensus-authorities", path = "../authorities" }
+slots = { package = "substrate-consensus-slots", path = "../slots"  }
+runtime_primitives = { package = "sr-primitives", path = "../../sr-primitives" }
+futures = "0.1.26"
+tokio = "0.1.18"
+parking_lot = "0.7.1"
+error-chain = "0.12.0"
+log = "0.4.6"
+
+[dependencies.schnorrkel]
+git = "https://github.com/paritytech/schnorrkel"
+branch = "master"
+
+[dev-dependencies]
+keyring = { package = "substrate-keyring", path = "../../keyring" }
+substrate-executor = { path = "../../executor" }
+network = { package = "substrate-network", path = "../../network", features = ["test-helpers"]}
+service = { package = "substrate-service", path = "../../service" }
+test_client = { package = "substrate-test-client", path = "../../test-client" }
+env_logger = "0.6.1"
@@ -0,0 +1,19 @@
+[package]
+name = "substrate-consensus-babe-primitives"
+version = "1.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+description = "Primitives for BABE consensus"
+edition = "2018"
+
+[dependencies]
+substrate-client = { path = "../../../client", default-features = false }
+runtime_primitives = { package = "sr-primitives", path = "../../../sr-primitives", default-features = false }
+slots = { package = "substrate-consensus-slots", path = "../../slots", optional = true }
+parity-codec = "^3.4.0"
+
+[features]
+default = ["std"]
+std = [
+	"substrate-client/std",
+	"slots",
+]
@@ -0,0 +1,76 @@
+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Primitives for BABE.
+#![forbid(warnings, unsafe_code, missing_docs)]
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use runtime_primitives::ConsensusEngineId;
+use substrate_client::decl_runtime_apis;
+
+use parity_codec::{Encode, Decode};
+
+/// The `ConsensusEngineId` of BABE.
+pub const BABE_ENGINE_ID: ConsensusEngineId = [b'b', b'a', b'b', b'e'];
+
+/// Configuration data used by the BABE consensus engine.
+#[derive(Copy, Clone, Hash, PartialEq, Eq, Debug, Encode, Decode)]
+pub struct BabeConfiguration {
+	slot_duration: u64,
+	expected_block_time: u64,
+}
+
+impl BabeConfiguration {
+	/// Return the expected block time in milliseconds for BABE.  Currently,
+	/// only the value provided by this type at genesis will be used.
+	///
+	/// Dynamic expected block time may be supported in the future.
+	pub fn expected_block_time(&self) -> u64 {
+		self.expected_block_time
+	}
+
+	/// Return the slot duration in milliseconds for BABE.  Currently, only
+	/// the value provided by this type at genesis will be used.
+	///
+	/// Dynamic slot duration may be supported in the future.
+	pub fn slot_duration(&self) -> u64 {
+		self.slot_duration
+	}
+}
+
+#[cfg(feature = "std")]
+impl slots::SlotData for BabeConfiguration {
+	/// Return the slot duration in milliseconds for BABE.  Currently, only
+	/// the value provided by this type at genesis will be used.
+	///
+	/// Dynamic slot duration may be supported in the future.
+	fn slot_duration(&self) -> u64 {
+		self.slot_duration
+	}
+
+	const SLOT_KEY: &'static [u8] = b"babe_bootstrap_data";
+}
+
+decl_runtime_apis! {
+	/// API necessary for block authorship with BABE.
+	pub trait BabeApi {
+		/// Return the configuration for BABE.  Currently,
+		/// only the value provided by this type at genesis will be used.
+		///
+		/// Dynamic configuration may be supported in the future.
+		fn startup_data() -> BabeConfiguration;
+	}
+}
@@ -0,0 +1,102 @@
+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! BABE (Blind Assignment for Blockchain Extension) consensus in substrate.
+#![forbid(warnings, unsafe_code, missing_docs)]
+
+pub use babe_primitives::*;
+use parity_codec::{Decode, Encode, Input};
+use runtime_primitives::generic;
+use primitives::sr25519::{
+	Public,
+	Signature,
+	LocalizedSignature,
+};
+
+use schnorrkel::{
+	SecretKey as Secret,
+	vrf::{VRFProof, VRF_PROOF_LENGTH},
+	PUBLIC_KEY_LENGTH, SIGNATURE_LENGTH,
+};
+
+/// A BABE seal.  It includes:
+/// 
+/// * The public key
+/// * The VRF proof
+/// * The signature
+/// * The slot number
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct BabeSeal {
+	proof: VRFProof,
+	signature: LocalizedSignature,
+	slot_num: u64,
+}
+
+impl Encode for BabeSeal {
+	fn encode(&self) -> Vec<u8> {
+		parity_codec::Encode::encode(&(
+			self.proof.to_bytes(),
+			self.signature.signature.0,
+			self.signature.signer.0,
+			self.slot_num,
+		))
+	}
+}
+
+impl Decode for BabeSeal {
+	fn decode<R: Input>(i: &mut R) -> Option<Self> {
+		let (public_key, proof, sig, slot_num): (
+			[u8; PUBLIC_KEY_LENGTH],
+			[u8; VRF_PROOF_LENGTH],
+			[u8; SIGNATURE_LENGTH],
+			u64,
+		) = Decode::decode(i)?;
+		Some(BabeSeal {
+			proof: VRFProof::from_bytes(&proof).ok()?,
+			signature: LocalizedSignature {
+				signature: Signature(sig),
+				signer: Public(public_key),
+			},
+			slot_num,
+		})
+	}
+}
+
+/// A digest item which is usable with BABE consensus.
+pub trait CompatibleDigestItem: Sized {
+	/// Construct a digest item which contains a slot number and a signature on the
+	/// hash.
+	fn babe_seal(signature: BabeSeal) -> Self;
+
+	/// If this item is an Babe seal, return the slot number and signature.
+	fn as_babe_seal(&self) -> Option<BabeSeal>;
+}
+
+impl<Hash> CompatibleDigestItem for generic::DigestItem<Hash, Public, Secret> {
+	/// Construct a digest item which is aaAASSAAAAAASDC   a slot number and a signature on the
+	/// hash.
+	fn babe_seal(signature: BabeSeal) -> Self {
+		generic::DigestItem::Consensus(BABE_ENGINE_ID, signature.encode())
+	}
+
+	/// If this item is an BABE seal, return the slot number and signature.
+	fn as_babe_seal(&self) -> Option<BabeSeal> {
+		match self {
+			generic::DigestItem::Consensus(BABE_ENGINE_ID, seal) => Decode::decode(&mut &seal[..]),
+			_ => None,
+		}
+	}
+}
@@ -1,5 +1,5 @@
 [package]
-name = "substrate-consensus-aura-slots"
+name = "substrate-consensus-slots"
 version = "1.0.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 description = "Generic slots-based utilities for consensus"
@@ -7,12 +7,11 @@ edition = "2018"

 [dependencies]
 codec = { package = "parity-codec", version = "3.2" }
-client = { package = "substrate-client", path = "../../../client" }
-primitives = { package = "substrate-primitives", path = "../../../primitives" }
-runtime_primitives = { package = "sr-primitives", path = "../../../sr-primitives" }
-aura_primitives = { package = "substrate-consensus-aura-primitives", path = "../primitives" }
-consensus_common = { package = "substrate-consensus-common", path = "../../common" }
-inherents = { package = "substrate-inherents", path = "../../../inherents" }
+client = { package = "substrate-client", path = "../../client" }
+primitives = { package = "substrate-primitives", path = "../../primitives" }
+runtime_primitives = { package = "sr-primitives", path = "../../sr-primitives" }
+consensus_common = { package = "substrate-consensus-common", path = "../common" }
+inherents = { package = "substrate-inherents", path = "../../inherents" }
 futures = "0.1.17"
 tokio = "0.1.7"
 parking_lot = "0.7.1"
@@ -14,25 +14,35 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.

+//! Slots functionality for Substrate.
+//!
+//! Some consensus algorithms have a concept of *slots*, which are intervals in
+//! time during which certain events can and/or must occur.  This crate
+//! provides generic functionality for slots.
+
+#![forbid(warnings, unsafe_code, missing_docs)]
+
 mod slots;

 pub use slots::{Slots, SlotInfo};

 use std::sync::{mpsc, Arc};
 use std::thread;
+use std::fmt::Debug;
 use futures::prelude::*;
 use futures::{Future, IntoFuture, future::{self, Either}};
 use log::{warn, debug, info};
 use runtime_primitives::generic::BlockId;
-use runtime_primitives::traits::{ProvideRuntimeApi, Block};
+use runtime_primitives::traits::{ProvideRuntimeApi, Block, ApiRef};
 use consensus_common::SyncOracle;
 use inherents::{InherentData, InherentDataProviders};
-use aura_primitives::AuraApi;
 use client::ChainHead;
-use codec::Encode;
+use codec::{Encode, Decode};

 /// A worker that should be invoked at every new slot.
 pub trait SlotWorker<B: Block> {
+	/// The type fo the future that will be returned when a new slot is
+	/// triggered.
 	type OnSlot: IntoFuture<Item=(), Error=consensus_common::Error>;

 	/// Called when the proposer starts.
@@ -61,8 +71,8 @@ pub fn inherent_to_common_error(err: inherents::RuntimeString) -> consensus_comm
 }

 /// Start a new slot worker in a separate thread.
-pub fn start_slot_worker_thread<B, C, W, SO, SC, OnExit>(
-	slot_duration: SlotDuration,
+pub fn start_slot_worker_thread<B, C, W, SO, SC, T, OnExit>(
+	slot_duration: SlotDuration<T>,
 	client: Arc<C>,
 	worker: Arc<W>,
 	sync_oracle: SO,
@@ -74,7 +84,8 @@ pub fn start_slot_worker_thread<B, C, W, SO, SC, OnExit>(
 	W: SlotWorker<B> + Send + Sync + 'static,
 	SO: SyncOracle + Send + Clone + 'static,
 	SC: SlotCompatible + 'static,
-	OnExit: Future<Item=(), Error=()> + Send + 'static
+	OnExit: Future<Item=(), Error=()> + Send + 'static,
+	T: SlotData + Send + Clone + 'static,
 {
 	use tokio::runtime::current_thread::Runtime;

@@ -89,8 +100,8 @@ pub fn start_slot_worker_thread<B, C, W, SO, SC, OnExit>(
 			}
 		};

-		let slot_worker_future = match start_slot_worker::<_, _, _, _, SC, _>(
-			slot_duration,
+		let slot_worker_future = match start_slot_worker::<_, _, _, _, _, SC, _>(
+			slot_duration.clone(),
 			client,
 			worker,
 			sync_oracle,
@@ -114,12 +125,12 @@ pub fn start_slot_worker_thread<B, C, W, SO, SC, OnExit>(
 		let _ = runtime.block_on(slot_worker_future);
 	});

-	result_recv.recv().expect("Aura start thread result sender dropped")
+	result_recv.recv().expect("Slots start thread result sender dropped")
 }

 /// Start a new slot worker.
-pub fn start_slot_worker<B, C, W, SO, SC, OnExit>(
-	slot_duration: SlotDuration,
+pub fn start_slot_worker<B, C, W, T, SO, SC, OnExit>(
+	slot_duration: SlotDuration<T>,
 	client: Arc<C>,
 	worker: Arc<W>,
 	sync_oracle: SO,
@@ -132,19 +143,20 @@ pub fn start_slot_worker<B, C, W, SO, SC, OnExit>(
 	SO: SyncOracle + Send + Clone,
 	SC: SlotCompatible,
 	OnExit: Future<Item=(), Error=()>,
+	T: SlotData + Clone,
 {
-	worker.on_start(slot_duration.0)?;
+	worker.on_start(slot_duration.slot_duration())?;

 	let make_authorship = move || {
 		let client = client.clone();
 		let worker = worker.clone();
 		let sync_oracle = sync_oracle.clone();
-		let SlotDuration(slot_duration) = slot_duration;
+		let SlotDuration(slot_duration) = slot_duration.clone();
 		let inherent_data_providers = inherent_data_providers.clone();

 		// rather than use a timer interval, we schedule our waits ourselves
-		Slots::<SC>::new(slot_duration, inherent_data_providers)
-			.map_err(|e| debug!(target: "aura", "Faulty timer: {:?}", e))
+		Slots::<SC>::new(slot_duration.slot_duration(), inherent_data_providers)
+			.map_err(|e| debug!(target: "slots", "Faulty timer: {:?}", e))
 			.for_each(move |slot_info| {
 				let client = client.clone();
 				let worker = worker.clone();
@@ -152,7 +164,7 @@ pub fn start_slot_worker<B, C, W, SO, SC, OnExit>(

 				// only propose when we are not syncing.
 				if sync_oracle.is_major_syncing() {
-					debug!(target: "aura", "Skipping proposal slot due to sync.");
+					debug!(target: "slots", "Skipping proposal slot due to sync.");
 					return Either::B(future::ok(()));
 				}

@@ -160,7 +172,7 @@ pub fn start_slot_worker<B, C, W, SO, SC, OnExit>(
 				let chain_head = match client.best_block_header() {
 					Ok(x) => x,
 					Err(e) => {
-						warn!(target: "aura", "Unable to author block in slot {}. \
+						warn!(target: "slots", "Unable to author block in slot {}. \
 							no best block header: {:?}", slot_num, e);
 						return Either::B(future::ok(()))
 					}
@@ -168,7 +180,7 @@ pub fn start_slot_worker<B, C, W, SO, SC, OnExit>(

 				Either::A(
 					worker.on_slot(chain_head, slot_info).into_future()
-						.map_err(|e| debug!(target: "aura", "Encountered aura error: {:?}", e))
+						.map_err(|e| debug!(target: "slots", "Encountered consensus error: {:?}", e))
 				)
 			})
 	};
@@ -178,13 +190,13 @@ pub fn start_slot_worker<B, C, W, SO, SC, OnExit>(
 		authorship_task.catch_unwind().then(|res| {
 			match res {
 				Ok(Ok(())) => (),
-				Ok(Err(())) => warn!("Aura authorship task terminated unexpectedly. Restarting"),
+				Ok(Err(())) => warn!(target: "slots", "Authorship task terminated unexpectedly. Restarting"),
 				Err(e) => {
 					if let Some(s) = e.downcast_ref::<&'static str>() {
-						warn!("Aura authorship task panicked at {:?}", s);
+						warn!(target: "slots", "Authorship task panicked at {:?}", s);
 					}

-					warn!("Restarting Aura authorship task");
+					warn!(target: "slots", "Restarting authorship task");
 				}
 			}

@@ -207,32 +219,49 @@ pub enum CheckedHeader<H, S> {
 	Checked(H, S),
 }

+/// A type from which a slot duration can be obtained.
+pub trait SlotData {
+	/// Gets the slot duration.
+	fn slot_duration(&self) -> u64;
+
+	/// The static slot key
+	const SLOT_KEY: &'static [u8];
+}
+
+impl SlotData for u64 {
+	fn slot_duration(&self) -> u64 { *self }
+
+	const SLOT_KEY: &'static [u8] = b"aura_slot_duration";
+}
+
 /// A slot duration. Create with `get_or_compute`.
 // The internal member should stay private here.
-#[derive(Clone, Copy, Debug)]
-pub struct SlotDuration(u64);
+#[derive(Clone, Copy, Debug, Encode, Decode, Hash, PartialOrd, Ord, PartialEq, Eq)]
+pub struct SlotDuration<T: Clone>(T);

-impl SlotDuration {
-	/// Either fetch the slot duration from disk or compute it from the genesis
-	/// state.
-	pub fn get_or_compute<B: Block, C>(client: &C) -> ::client::error::Result<Self> where
+impl<T: Clone> SlotDuration<T> {
+	/// Either fetch the slot duration from disk or compute it from the
+	/// genesis state.
+	///
+	/// `slot_key` is marked as `'static`, as it should really be a
+	/// compile-time constant.
+	pub fn get_or_compute<B: Block, C, CB>(client: &C, cb: CB) -> ::client::error::Result<Self> where
 		C: client::backend::AuxStore,
 		C: ProvideRuntimeApi,
-		C::Api: AuraApi<B>,
+		CB: FnOnce(ApiRef<C::Api>, &BlockId<B>) -> ::client::error::Result<T>,
+		T: SlotData + Encode + Decode + Debug,
 	{
-		use codec::Decode;
-		const SLOT_KEY: &[u8] = b"aura_slot_duration";
-
-		match client.get_aux(SLOT_KEY)? {
-			Some(v) => u64::decode(&mut &v[..])
+		match client.get_aux(T::SLOT_KEY)? {
+			Some(v) => <T as codec::Decode>::decode(&mut &v[..])
 				.map(SlotDuration)
 				.ok_or_else(|| ::client::error::Error::Backend(
-					format!("Aura slot duration kept in invalid format"),
+					format!("slot duration kept in invalid format"),
 				).into()),
 			None => {
 				use runtime_primitives::traits::Zero;
-				let genesis_slot_duration = client.runtime_api()
-					.slot_duration(&BlockId::number(Zero::zero()))?;
+				let genesis_slot_duration = cb(
+					client.runtime_api(),
+					&BlockId::number(Zero::zero()))?;

 				info!(
 					"Loaded block-time = {:?} seconds from genesis on first-launch",
@@ -240,7 +269,7 @@ impl SlotDuration {
 				);

 				genesis_slot_duration.using_encoded(|s| {
-					client.insert_aux(&[(SLOT_KEY, &s[..])], &[])
+					client.insert_aux(&[(T::SLOT_KEY, &s[..])], &[])
 				})?;

 				Ok(SlotDuration(genesis_slot_duration))
@@ -248,8 +277,15 @@ impl SlotDuration {
 		}
 	}

-	/// Returns slot duration value.
-	pub fn get(&self) -> u64 {
-		self.0
+	/// Returns slot data value.
+	pub fn get(&self) -> T {
+		self.0.clone()
+	}
+
+	/// Get the slot duration in milliseconds
+	pub fn slot_duration(&self) -> u64
+		where T: SlotData
+	{
+		self.0.slot_duration()
 	}
 }
@@ -6,12 +6,12 @@ edition = "2018"

 [dependencies]
 rstd = { package = "sr-std", path = "../sr-std", default-features = false }
-parity-codec = { version = "3.3", default-features = false, features = ["derive"] }
+parity-codec = { version = "3.4.0", default-features = false, features = ["derive"] }
 rustc-hex = { version = "2.0", default-features = false }
 serde = { version = "1.0", optional = true }
 serde_derive = { version = "1.0", optional = true }
-twox-hash = { version = "1.1.0", optional = true }
-byteorder = { version = "1.1", default-features = false }
+twox-hash = { version = "1.2.0", optional = true }
+byteorder = { version = "1.3.1", default-features = false }
 primitive-types = { version = "0.2", default-features = false, features = ["codec"] }
 impl-serde = { version = "0.1", optional = true }
 wasmi = { version = "0.4.3", optional = true }
@@ -26,14 +26,14 @@ schnorrkel = { version = "0.1", optional = true }
 rand = { version = "0.6", optional = true }
 sha2 = { version = "0.8", optional = true }
 substrate-bip39 = { git = "https://github.com/paritytech/substrate-bip39", optional = true }
-tiny-bip39 = { version = "0.6.0", optional = true }
+tiny-bip39 = { version = "0.6.1", optional = true }
 hex = { version = "0.3", optional = true }
 regex = {version = "1.1", optional = true }

 [dev-dependencies]
 substrate-serializer = { path = "../serializer" }
-pretty_assertions = "0.5"
-heapsize = "0.4"
+pretty_assertions = "0.6.1"
+heapsize = "0.4.2"

 [features]
 default = ["std"]
@@ -231,8 +231,10 @@ pub struct LocalizedSignature {
 impl Signature {
 	/// A new instance from the given 64-byte `data`.
 	///
-	/// NOTE: No checking goes on to ensure this is a real signature. Only use it if
-	/// you are certain that the array actually is a signature. GIGO!
+	/// NOTE: No checking goes on to ensure this is a real signature. Only use
+	/// it if you are certain that the array actually is a signature, or if you
+	/// immediately verify the signature.  All functions that verify signatures
+	/// will fail if the `Signature` is not actually a valid signature.
 	pub fn from_raw(data: [u8; 64]) -> Signature {
 		Signature(data)
 	}
@@ -8,8 +8,8 @@ edition = "2018"
 proc-macro = true

 [dependencies]
-quote = "0.6"
-syn = { version = "^0.15.22", features = [ "full", "fold", "extra-traits", "visit" ] }
+quote = "0.6.12"
+syn = { version = "^0.15.30", features = [ "full", "fold", "extra-traits", "visit" ] }
 proc-macro2 = "0.4"
 blake2-rfc = "0.2"
 proc-macro-crate = "0.1.3"
@@ -72,7 +72,10 @@ pub enum DigestItem<Hash, AuthorityId, SealSignature> {
 	/// trie creation.
 	ChangesTrieRoot(Hash),
 	/// The old way to put a Seal on it.  Deprecated.
-	#[deprecated]
+	#[deprecated(
+		since = "1.0",
+		note = "New versions of Substrate will never generate this, and it will be rejected on new blockchains.",
+	)]
 	Seal(u64, SealSignature),
 	/// Put a Seal on it
 	Consensus(ConsensusEngineId, Vec<u8>),
@@ -319,7 +319,6 @@ fn code_using_trie() -> u64 {
 	iter_pairs.len() as u64
 }

-
 cfg_if! {
 	if #[cfg(feature = "std")] {
 		impl_runtime_apis! {
@@ -59,8 +59,8 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	spec_name: create_runtime_str!("node"),
 	impl_name: create_runtime_str!("substrate-node"),
 	authoring_version: 10,
-	spec_version: 59,
-	impl_version: 60,
+	spec_version: 62,
+	impl_version: 62,
 	apis: RUNTIME_API_VERSIONS,
 };

@@ -11,6 +11,6 @@ proc-macro = true
 srml-support-procedural-tools = { path = "./tools" }
 sr-api-macros = { path = "../../../core/sr-api-macros" }

-proc-macro2 = "0.4"
-quote = { version = "0.6" }
-syn = { version = "0.15", features = ["full"] }
+proc-macro2 = "0.4.27"
+quote = { version = "0.6.12" }
+syn = { version = "0.15.30", features = ["full"] }
@@ -6,7 +6,7 @@ edition = "2018"

 [dependencies]
 srml-support-procedural-tools-derive = { path = "./derive" }
-proc-macro2 = "0.4"
-quote = { version = "0.6" }
-syn = { version = "0.15", features = ["full"] }
+proc-macro2 = "0.4.27"
+quote = { version = "0.6.12" }
+syn = { version = "0.15.30", features = ["full"] }
 proc-macro-crate = "0.1.3"
@@ -8,6 +8,6 @@ edition = "2018"
 proc-macro = true

 [dependencies]
-proc-macro2 = "0.4.24"
-quote = { version = "0.6.10", features = ["proc-macro"] }
-syn = { version = "0.15.21", features = ["proc-macro" ,"full", "extra-traits", "parsing"] }
+proc-macro2 = "0.4.27"
+quote = { version = "0.6.12", features = ["proc-macro"] }
+syn = { version = "0.15.30", features = ["proc-macro" ,"full", "extra-traits", "parsing"] }