Aura consensus for parachains (#371)

* Update polkadot

* Migrate all uses of MQC heads to merkle proofs

* Mass rename `relay_parent_storage_root`

* Restore parachain-system tests

* Update polkadot and libp2p swarm for testing

* Collapse match into an if let

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Start with something

* Update Substrate & Polkadot

* Start to make it compile

* Make it compile

* Begin with something

* Yep

* I'm a hacker

* Bring back the builder

* Make it work in some way

* Compile

* Parachains use their own "slot"

* Adds cumulus-pallet-aura

* Wrap AuRa import queue to disable equivocation checking by default

* Pass slot duration

* Check the seal when validating a block

* Adds missing file

* Try to make the seal working

* Fix it

* Some fixes

* Bring in the latest features to cleanup the code

* Update and make it compile

* Improve the import

* Start fixing

* More work

* Fix fix fix

* Make everything compile

* Small cleanups

* Rename and more docs

* Docs

* Fixes fixes fixes

* Update rococo-parachains/src/chain_spec.rs

* Update client/consensus/aura/src/lib.rs

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

* Update client/consensus/aura/src/lib.rs

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

* Update primitives/parachain-inherent/Cargo.toml

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

* Update primitives/parachain-inherent/Cargo.toml

* Update primitives/parachain-inherent/Cargo.toml

* Update primitives/parachain-inherent/Cargo.toml

Co-authored-by: Sergei Shulepov <sergei@parity.io>
Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

Cargo.toml

@@ -1,10 +1,12 @@
 [workspace]
 members = [
 	"client/cli",
+	"client/consensus/aura",
 	"client/consensus/common",
 	"client/consensus/relay-chain",
 	"client/network",
 	"client/service",
+	"pallets/aura-ext",
 	"pallets/dmp-queue",
 	"pallets/parachain-system",
 	"pallets/xcm",

client/consensus/aura/Cargo.toml

@@ -0,0 +1,38 @@
+[package]
+name = "cumulus-client-consensus-aura"
+description = "AURA consensus algorithm for parachains"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+
+[dependencies]
+# Substrate dependencies
+sp-consensus = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-inherents = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-blockchain = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-block-builder = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-api = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-consensus-aura = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-keystore = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-application-crypto = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sc-client-api = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sc-consensus-aura = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sc-consensus-slots = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sc-telemetry = { git = "https://github.com/paritytech/substrate", branch = "master" }
+substrate-prometheus-endpoint = { git = "https://github.com/paritytech/substrate", branch = "master" }
+
+# Polkadot dependencies
+polkadot-service = { git = "https://github.com/paritytech/polkadot", branch = "master" }
+
+# Cumulus dependencies
+cumulus-client-consensus-common = { path = "../common" }
+cumulus-primitives-core = { path = "../../../primitives/core" }
+
+# Other deps
+futures = { version = "0.3.8", features = ["compat"] }
+codec = { package = "parity-scale-codec", version = "2.0.0", features = [ "derive" ] }
+tracing = "0.1.22"
+async-trait = "0.1.42"
+parking_lot = "0.9"

client/consensus/aura/src/import_queue.rs

@@ -0,0 +1,101 @@
+// Copyright 2021 Parity Technologies (UK) Ltd.
+// This file is part of Cumulus.
+
+// Cumulus 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.
+
+// Cumulus 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 Cumulus.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Parachain specific wrapper for the AuRa import queue.
+
+use codec::Codec;
+use sc_client_api::{backend::AuxStore, BlockOf};
+use sc_consensus_slots::InherentDataProviderExt;
+use sp_api::{ApiExt, ProvideRuntimeApi};
+use sp_block_builder::BlockBuilder as BlockBuilderApi;
+use sp_blockchain::{HeaderBackend, ProvideCache};
+use sp_consensus::{
+	import_queue::DefaultImportQueue, BlockImport, CanAuthorWith, Error as ConsensusError,
+};
+use sp_consensus_aura::{digests::CompatibleDigestItem, AuraApi};
+use sp_core::crypto::Pair;
+use sp_inherents::CreateInherentDataProviders;
+use sp_runtime::traits::{Block as BlockT, DigestItemFor};
+use std::{fmt::Debug, hash::Hash, sync::Arc};
+use substrate_prometheus_endpoint::Registry;
+use sc_telemetry::TelemetryHandle;
+
+/// Parameters of [`import_queue`].
+pub struct ImportQueueParams<'a, I, C, IDP, S, CAW> {
+	/// The block import to use.
+	pub block_import: I,
+	/// The client to interact with the chain.
+	pub client: Arc<C>,
+	/// The inherent data providers, to create the inherent data.
+	pub create_inherent_data_providers: IDP,
+	/// The spawner to spawn background tasks.
+	pub spawner: &'a S,
+	/// The prometheus registry.
+	pub registry: Option<&'a Registry>,
+	/// Can we author with the current node?
+	pub can_author_with: CAW,
+	/// The telemetry handle.
+	pub telemetry: Option<TelemetryHandle>,
+}
+
+/// Start an import queue for the Aura consensus algorithm.
+pub fn import_queue<'a, P, Block, I, C, S, CAW, IDP>(
+	ImportQueueParams {
+		block_import,
+		client,
+		create_inherent_data_providers,
+		spawner,
+		registry,
+		can_author_with,
+		telemetry,
+	}: ImportQueueParams<'a, I, C, IDP, S, CAW>,
+) -> Result<DefaultImportQueue<Block, C>, sp_consensus::Error>
+where
+	Block: BlockT,
+	C::Api: BlockBuilderApi<Block> + AuraApi<Block, P::Public> + ApiExt<Block>,
+	C: 'static
+		+ ProvideRuntimeApi<Block>
+		+ BlockOf
+		+ ProvideCache<Block>
+		+ Send
+		+ Sync
+		+ AuxStore
+		+ HeaderBackend<Block>,
+	I: BlockImport<Block, Error = ConsensusError, Transaction = sp_api::TransactionFor<C, Block>>
+		+ Send
+		+ Sync
+		+ 'static,
+	DigestItemFor<Block>: CompatibleDigestItem<P::Signature>,
+	P: Pair + Send + Sync + 'static,
+	P::Public: Clone + Eq + Send + Sync + Hash + Debug + Codec,
+	P::Signature: Codec,
+	S: sp_core::traits::SpawnEssentialNamed,
+	CAW: CanAuthorWith<Block> + Send + Sync + 'static,
+	IDP: CreateInherentDataProviders<Block, ()> + Sync + Send + 'static,
+	IDP::InherentDataProviders: InherentDataProviderExt + Send + Sync,
+{
+	sc_consensus_aura::import_queue::<P, _, _, _, _, _, _>(sc_consensus_aura::ImportQueueParams {
+		block_import: crate::ParachainBlockImport(block_import),
+		justification_import: None,
+		client,
+		create_inherent_data_providers,
+		spawner,
+		registry,
+		can_author_with,
+		check_for_equivocation: sc_consensus_aura::CheckForEquivocation::No,
+		telemetry,
+	})
+}