Consensus message buffering and more (#114)

* CLI options and keystore integration

* Replace multiqueue with future::mpsc

* BFT gossip

* Revert to app_dirs

* generate_from_seed commented

* Refactor event loop

* Start consensus by timer

* Message buffering

* Minor fixes

* Work around duty-roster issue.

* some more minor fixes

* fix compilation

* more consistent formatting

* make bft input stream never conclude

* Minor fixes

* add timestamp module to executive

* more cleanups and logging

* Fixed message propagation

polkadot/api/Cargo.toml

@@ -10,6 +10,7 @@ polkadot-runtime = { path = "../runtime" }
 polkadot-primitives = { path = "../primitives" }
 substrate-codec = { path = "../../substrate/codec" }
 substrate-runtime-io = { path = "../../substrate/runtime-io" }
+substrate-runtime-executive = { path  = "../../substrate/runtime/executive" }
 substrate-client = { path = "../../substrate/client" }
 substrate-primitives = { path = "../../substrate/primitives" }
 substrate-executor = { path = "../../substrate/executor" }

polkadot/api/src/lib.rs

@@ -24,6 +24,7 @@ extern crate substrate_codec as codec;
 extern crate substrate_runtime_io as runtime_io;
 extern crate substrate_client as client;
 extern crate substrate_executor as substrate_executor;
+extern crate substrate_runtime_executive;
 extern crate substrate_primitives;
 extern crate substrate_state_machine as state_machine;
 
@@ -323,16 +324,19 @@ impl<S: state_machine::Backend> BlockBuilder for ClientBlockBuilder<S>
 	}
 
 	fn bake(mut self) -> Block {
+		use substrate_runtime_executive::extrinsics_root;
+
 		let mut ext = state_machine::Ext {
 			overlay: &mut self.changes,
 			backend: &self.state,
 		};
 
-		let final_header = ::substrate_executor::with_native_environment(
+		let mut final_header = ::substrate_executor::with_native_environment(
 			&mut ext,
 			move || runtime::Executive::finalise_block()
 		).expect("all inherent extrinsics pushed; all other extrinsics executed correctly; qed");
 
+		final_header.extrinsics_root = extrinsics_root::<runtime_io::BlakeTwo256, _>(&self.extrinsics);
 		Block {
 			header: final_header,
 			extrinsics: self.extrinsics,
@@ -404,6 +408,7 @@ mod tests {
 		let block = block_builder.bake();
 
 		assert_eq!(block.header.number, 1);
+		assert!(block.header.extrinsics_root != Default::default());
 	}
 
 	#[test]

polkadot/cli/Cargo.toml

@@ -12,7 +12,7 @@ log = "0.3"
 hex-literal = "0.1"
 triehash = "0.1"
 ed25519 = { path = "../../substrate/ed25519" }
-app_dirs = "1.2.1"
+app_dirs = "1.2"
 substrate-client = { path = "../../substrate/client" }
 substrate-codec = { path = "../../substrate/codec" }
 substrate-runtime-io = { path = "../../substrate/runtime-io" }

polkadot/cli/src/lib.rs

@@ -43,6 +43,7 @@ pub mod error;
 
 use std::path::{Path, PathBuf};
 use std::net::SocketAddr;
+use std::sync::mpsc;
 
 /// Parse command line arguments and start the node.
 ///
@@ -52,7 +53,7 @@ use std::net::SocketAddr;
 /// 9556-9591		Unassigned
 /// 9803-9874		Unassigned
 /// 9926-9949		Unassigned
-pub fn run<I, T>(args: I) -> error::Result<()> where
+pub fn run<I, T>(args: I, exit: mpsc::Receiver<()>) -> error::Result<()> where
 	I: IntoIterator<Item = T>,
 	T: Into<std::ffi::OsString> + Clone,
 {
@@ -116,9 +117,9 @@ pub fn run<I, T>(args: I) -> error::Result<()> where
 		address.set_port(rpc_port);
 	}
 	let handler = rpc::rpc_handler(service.client());
-	let server = rpc::start_http(&address, handler)?;
+	let _server = rpc::start_http(&address, handler)?;
 
-	server.wait();
+	exit.recv().ok();
 	Ok(())
 }
 

polkadot/consensus/Cargo.toml

@@ -6,7 +6,7 @@ authors = ["Parity Technologies <admin@parity.io>"]
 [dependencies]
 futures = "0.1.17"
 parking_lot = "0.4"
-tokio-timer = "0.1.2"
+tokio-core = "0.1.12"
 ed25519 = { path = "../../substrate/ed25519" }
 error-chain = "0.11"
 log = "0.4"
@@ -21,6 +21,5 @@ substrate-codec = { path = "../../substrate/codec" }
 substrate-primitives = { path = "../../substrate/primitives" }
 substrate-runtime-support = { path = "../../substrate/runtime-support" }
 substrate-network = { path = "../../substrate/network" }
-tokio-core = "0.1.12"
 substrate-keyring = { path = "../../substrate/keyring" }
 substrate-client = { path = "../../substrate/client" }

polkadot/consensus/src/lib.rs

@@ -32,7 +32,6 @@
 extern crate futures;
 extern crate ed25519;
 extern crate parking_lot;
-extern crate tokio_timer;
 extern crate polkadot_api;
 extern crate polkadot_collator as collator;
 extern crate polkadot_statement_table as table;
@@ -532,6 +531,8 @@ impl<C: PolkadotApi, R: TableRouter> bft::Proposer for Proposer<C, R> {
 	type Evaluate = Result<bool, Error>;
 
 	fn propose(&self) -> Result<SubstrateBlock, Error> {
+		debug!(target: "bft", "proposing block on top of parent ({}, {:?})", self.parent_number, self.parent_hash);
+
 		// TODO: handle case when current timestamp behind that in state.
 		let mut block_builder = self.client.build_block(
 			&self.parent_id,
@@ -577,7 +578,18 @@ impl<C: PolkadotApi, R: TableRouter> bft::Proposer for Proposer<C, R> {
 
 	// TODO: certain kinds of errors here should lead to a misbehavior report.
 	fn evaluate(&self, proposal: &SubstrateBlock) -> Result<bool, Error> {
-		evaluate_proposal(proposal, &*self.client, current_timestamp(), &self.parent_hash, &self.parent_id)
+		debug!(target: "bft", "evaluating block on top of parent ({}, {:?})", self.parent_number, self.parent_hash);
+		match evaluate_proposal(proposal, &*self.client, current_timestamp(), &self.parent_hash, &self.parent_id) {
+			Ok(x) => Ok(x),
+			Err(e) => match *e.kind() {
+				ErrorKind::PolkadotApi(polkadot_api::ErrorKind::Executor(_)) => Ok(false),
+				ErrorKind::ProposalNotForPolkadot => Ok(false),
+				ErrorKind::TimestampInFuture => Ok(false),
+				ErrorKind::WrongParentHash(_, _) => Ok(false),
+				ErrorKind::ProposalTooLarge(_) => Ok(false),
+				_ => Err(e),
+			}
+		}
 	}
 
 	fn import_misbehavior(&self, misbehavior: Vec<(AuthorityId, bft::Misbehavior)>) {

polkadot/consensus/src/service.rs

@@ -20,12 +20,14 @@
 /// candidate agreement over the network.
 
 use std::thread;
+use std::time::{Duration, Instant};
 use std::sync::Arc;
-use futures::{future, Future, Stream, Sink, Async, Canceled};
+use std::collections::{HashMap, VecDeque};
+use futures::{future, Future, Stream, Sink, Async, Canceled, Poll};
 use parking_lot::Mutex;
 use substrate_network as net;
 use tokio_core::reactor;
-use client::BlockchainEvents;
+use client::{BlockchainEvents, ChainHead};
 use runtime_support::Hashable;
 use primitives::{Hash, AuthorityId};
 use primitives::block::{Id as BlockId, HeaderHash, Header};
@@ -35,15 +37,101 @@ use bft::{self, BftService};
 use transaction_pool::TransactionPool;
 use ed25519;
 use super::{TableRouter, SharedTable, ProposerFactory};
-use error::Error;
+use error;
+
+const TIMER_DELAY_MS: u64 = 5000;
+const TIMER_INTERVAL_MS: u64 = 500;
+const MESSAGE_LIFETIME_SEC: u64 = 10;
 
 struct BftSink<E> {
 	network: Arc<net::ConsensusService>,
+	parent_hash: HeaderHash,
 	_e: ::std::marker::PhantomData<E>,
 }
 
-fn process_message(msg: net::BftMessage, authorities: &[AuthorityId], parent_hash: HeaderHash) -> Result<bft::Communication, bft::Error> {
-	Ok(match msg {
+#[derive(Clone)]
+struct SharedMessageCollection {
+	/// Messages for consensus over a block with known hash. Also holds timestamp of the first message.
+	messages: Arc<Mutex<HashMap<HeaderHash, (Instant, VecDeque<net::LocalizedBftMessage>)>>>,
+}
+
+impl SharedMessageCollection {
+	fn new() -> SharedMessageCollection {
+		SharedMessageCollection {
+			messages: Arc::new(Mutex::new(HashMap::new())),
+		}
+	}
+
+	fn select(&self, parent_hash: HeaderHash, stream: net::BftMessageStream, authorities: Vec<AuthorityId>) -> Messages {
+		Messages {
+			messages: self.messages.lock().remove(&parent_hash).map(|(_, m)| m).unwrap_or_else(VecDeque::new),
+			parent_hash,
+			network_stream: stream,
+			authorities: authorities,
+			collection: self.clone(),
+		}
+	}
+
+	fn push(&self, message: net::LocalizedBftMessage) {
+		self.messages.lock()
+			.entry(message.parent_hash)
+			.or_insert_with(|| (Instant::now(), VecDeque::new()))
+			.1.push_back(message);
+	}
+
+	fn collect_garbage(&self) {
+		let expiration = Duration::from_secs(MESSAGE_LIFETIME_SEC);
+		let now = Instant::now();
+		self.messages.lock().retain(|_, &mut (timestamp, _)| timestamp < now + expiration);
+	}
+}
+
+struct Messages {
+	parent_hash: HeaderHash,
+	messages: VecDeque<net::LocalizedBftMessage>,
+	network_stream: net::BftMessageStream,
+	authorities: Vec<AuthorityId>,
+	collection: SharedMessageCollection,
+}
+
+impl Stream for Messages {
+	type Item = bft::Communication;
+	type Error = bft::Error;
+
+	fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error> {
+		// push buffered messages first
+		while let Some(message) = self.messages.pop_front() {
+			match process_message(message, &self.authorities) {
+				Ok(message) => return Ok(Async::Ready(Some(message))),
+				Err(e) => debug!("Message validation failed: {:?}", e),
+			}
+		}
+
+		// check the network
+		match self.network_stream.poll() {
+			Err(_) => Err(bft::InputStreamConcluded.into()),
+			Ok(Async::NotReady) => Ok(Async::NotReady),
+			Ok(Async::Ready(None)) => Ok(Async::NotReady), // the input stream for agreements is never meant to logically end.
+			Ok(Async::Ready(Some(message))) => {
+				if message.parent_hash == self.parent_hash {
+					match process_message(message, &self.authorities) {
+						Ok(message) => Ok(Async::Ready(Some(message))),
+						Err(e) => {
+							debug!("Message validation failed: {:?}", e);
+							Ok(Async::NotReady)
+						}
+					}
+				} else {
+					self.collection.push(message);
+					Ok(Async::NotReady)
+				}
+			}
+		}
+	}
+}
+
+fn process_message(msg: net::LocalizedBftMessage, authorities: &[AuthorityId]) -> Result<bft::Communication, bft::Error> {
+	Ok(match msg.message {
 		net::BftMessage::Consensus(c) => bft::generic::Communication::Consensus(match c {
 			net::SignedConsensusMessage::Propose(proposal) => bft::generic::LocalizedMessage::Propose({
 				let proposal = bft::generic::LocalizedProposal {
@@ -60,7 +148,7 @@ fn process_message(msg: net::BftMessage, authorities: &[AuthorityId], parent_has
 						signer: ed25519::Public(proposal.sender),
 					}
 				};
-				bft::check_proposal(authorities, &parent_hash, &proposal)?;
+				bft::check_proposal(authorities, &msg.parent_hash, &proposal)?;
 				proposal
 			}),
 			net::SignedConsensusMessage::Vote(vote) => bft::generic::LocalizedMessage::Vote({
@@ -76,14 +164,14 @@ fn process_message(msg: net::BftMessage, authorities: &[AuthorityId], parent_has
 						net::ConsensusVote::AdvanceRound(r) => bft::generic::Vote::AdvanceRound(r as usize),
 					}
 				};
-				bft::check_vote(authorities, &parent_hash, &vote)?;
+				bft::check_vote(authorities, &msg.parent_hash, &vote)?;
 				vote
 			}),
 		}),
 		net::BftMessage::Auxiliary(a) => {
 			let justification = bft::UncheckedJustification::from(a);
 			// TODO: get proper error
-			let justification: Result<_, bft::Error> = bft::check_prepare_justification(authorities, parent_hash, justification)
+			let justification: Result<_, bft::Error> = bft::check_prepare_justification(authorities, msg.parent_hash, justification)
 				.map_err(|_| bft::ErrorKind::InvalidJustification.into());
 			bft::generic::Communication::Auxiliary(justification?)
 		},
@@ -96,27 +184,30 @@ impl<E> Sink for BftSink<E> {
 	type SinkError = E;
 
 	fn start_send(&mut self, message: bft::Communication) -> ::futures::StartSend<bft::Communication, E> {
-		let network_message = match message {
-			bft::generic::Communication::Consensus(c) => net::BftMessage::Consensus(match c {
-				bft::generic::LocalizedMessage::Propose(proposal) => net::SignedConsensusMessage::Propose(net::SignedConsensusProposal {
-					round_number: proposal.round_number as u32,
-					proposal: proposal.proposal,
-					digest: proposal.digest,
-					sender: proposal.sender,
-					digest_signature: proposal.digest_signature.signature,
-					full_signature: proposal.full_signature.signature,
+		let network_message = net::LocalizedBftMessage {
+			message: match message {
+				bft::generic::Communication::Consensus(c) => net::BftMessage::Consensus(match c {
+					bft::generic::LocalizedMessage::Propose(proposal) => net::SignedConsensusMessage::Propose(net::SignedConsensusProposal {
+						round_number: proposal.round_number as u32,
+						proposal: proposal.proposal,
+						digest: proposal.digest,
+						sender: proposal.sender,
+						digest_signature: proposal.digest_signature.signature,
+						full_signature: proposal.full_signature.signature,
+					}),
+					bft::generic::LocalizedMessage::Vote(vote) => net::SignedConsensusMessage::Vote(net::SignedConsensusVote {
+						sender: vote.sender,
+						signature: vote.signature.signature,
+						vote: match vote.vote {
+							bft::generic::Vote::Prepare(r, h) => net::ConsensusVote::Prepare(r as u32, h),
+							bft::generic::Vote::Commit(r, h) => net::ConsensusVote::Commit(r as u32, h),
+							bft::generic::Vote::AdvanceRound(r) => net::ConsensusVote::AdvanceRound(r as u32),
+						}
+					}),
 				}),
-				bft::generic::LocalizedMessage::Vote(vote) => net::SignedConsensusMessage::Vote(net::SignedConsensusVote {
-					sender: vote.sender,
-					signature: vote.signature.signature,
-					vote: match vote.vote {
-						bft::generic::Vote::Prepare(r, h) => net::ConsensusVote::Prepare(r as u32, h),
-						bft::generic::Vote::Commit(r, h) => net::ConsensusVote::Commit(r as u32, h),
-						bft::generic::Vote::AdvanceRound(r) => net::ConsensusVote::AdvanceRound(r as u32),
-					}
-				}),
-			}),
-			bft::generic::Communication::Auxiliary(justification) => net::BftMessage::Auxiliary(justification.uncheck().into()),
+				bft::generic::Communication::Auxiliary(justification) => net::BftMessage::Auxiliary(justification.uncheck().into()),
+			},
+			parent_hash: self.parent_hash,
 		};
 		self.network.send_bft_message(network_message);
 		Ok(::futures::AsyncSink::Ready)
@@ -134,17 +225,49 @@ pub struct Service {
 
 struct Network(Arc<net::ConsensusService>);
 
+fn start_bft<F, C>(
+	header: &Header,
+	handle: reactor::Handle,
+	client: &bft::Authorities,
+	network: Arc<net::ConsensusService>,
+	bft_service: &BftService<F, C>,
+	messages: SharedMessageCollection
+) where
+	F: bft::ProposerFactory + 'static,
+	C: bft::BlockImport + bft::Authorities + 'static,
+	<F as bft::ProposerFactory>::Error: ::std::fmt::Debug,
+	<F::Proposer as bft::Proposer>::Error: ::std::fmt::Display + Into<error::Error>,
+{
+	let hash = header.blake2_256().into();
+	if bft_service.live_agreement().map_or(false, |h| h == hash) {
+		return;
+	}
+	let authorities = match client.authorities(&BlockId::Hash(hash)) {
+		Ok(authorities) => authorities,
+		Err(e) => {
+			debug!("Error reading authorities: {:?}", e);
+			return;
+		}
+	};
+	let input = messages.select(hash, network.bft_messages(), authorities).map_err(|e| e.into());
+	let output = BftSink { network: network, parent_hash: hash.clone(), _e: Default::default() };
+	match bft_service.build_upon(&header, input, output) {
+		Ok(Some(bft)) => handle.spawn(bft),
+		Ok(None) => {},
+		Err(e) => debug!("BFT agreement error: {:?}", e),
+	}
+}
+
 impl Service {
 	/// Create and start a new instance.
 	pub fn new<C>(
 		client: Arc<C>,
 		network: Arc<net::ConsensusService>,
 		transaction_pool: Arc<Mutex<TransactionPool>>,
-		key: ed25519::Pair,
-		best_header: &Header) -> Service
-		where C: BlockchainEvents + bft::BlockImport + bft::Authorities + PolkadotApi + Send + Sync + 'static
+		key: ed25519::Pair
+	) -> Service
+		where C: BlockchainEvents + ChainHead + bft::BlockImport + bft::Authorities + PolkadotApi + Send + Sync + 'static
 	{
-		let best_header = best_header.clone();
 		let thread = thread::spawn(move || {
 			let mut core = reactor::Core::new().expect("tokio::Core could not be created");
 			let key = Arc::new(key);
@@ -153,31 +276,44 @@ impl Service {
 				transaction_pool: transaction_pool.clone(),
 				network: Network(network.clone()),
 			};
-			let bft_service = BftService::new(client.clone(), key, factory);
-			let build_bft = |header: &Header| -> Result<_, Error> {
-				let hash = header.blake2_256().into();
-				let authorities = client.authorities(&BlockId::Hash(hash))?;
-				let input = network.bft_messages()
-					.filter_map(move |message| {
-						process_message(message, &authorities, hash.clone())
-							.map_err(|e| debug!("Message validation failed: {:?}", e))
-							.ok()
-					})
-					.map_err(|_| bft::InputStreamConcluded.into());
-				let output = BftSink { network: network.clone(), _e: Default::default() };
-				Ok(bft_service.build_upon(&header, input, output)?)
+			let messages = SharedMessageCollection::new();
+			let bft_service = Arc::new(BftService::new(client.clone(), key, factory));
+
+			let handle = core.handle();
+			let notifications = client.import_notification_stream().for_each(|notification| {
+				if notification.is_new_best {
+					start_bft(&notification.header, handle.clone(), &*client, network.clone(), &*bft_service, messages.clone());
+				}
+				Ok(())
+			});
+
+			let interval = reactor::Interval::new_at(Instant::now() + Duration::from_millis(TIMER_DELAY_MS), Duration::from_millis(TIMER_INTERVAL_MS), &handle).unwrap();
+			let mut prev_best = match client.best_block_header() {
+				Ok(header) => header.blake2_256(),
+				Err(e) => {
+					warn!("Cant's start consensus service. Error reading best block header: {:?}", e);
+					return;
+				}
 			};
-			// Kickstart BFT agreement on start.
-			if let Err(e) = build_bft(&best_header)
-				.map_err(|e| debug!("Error creating initial BFT agreement: {:?}", e))
-				.and_then(|bft| core.run(bft))
-			{
-				debug!("Error starting initial BFT agreement: {:?}", e);
-			}
-			let bft = client.import_notification_stream().and_then(|notification| {
-				build_bft(&notification.header).map_err(|e| debug!("BFT agreement error: {:?}", e))
-			}).for_each(|f| f);
-			if let Err(e) = core.run(bft) {
+			let c = client.clone();
+			let s = bft_service.clone();
+			let n = network.clone();
+			let m = messages.clone();
+			let handle = core.handle();
+			let timed = interval.map_err(|e| debug!("Timer error: {:?}", e)).for_each(move |_| {
+				if let Ok(best_block) = c.best_block_header() {
+					let hash = best_block.blake2_256();
+					m.collect_garbage();
+					if hash == prev_best {
+						debug!("Starting consensus round after a timeout");
+						start_bft(&best_block, handle.clone(), &*c, n.clone(), &*s, m.clone());
+					}
+					prev_best = hash;
+				}
+				Ok(())
+			});
+			core.handle().spawn(timed);
+			if let Err(e) = core.run(notifications) {
 				debug!("BFT event loop error {:?}", e);
 			}
 		});
@@ -235,3 +371,4 @@ impl TableRouter for Router {
 		future::ok(Extrinsic)
 	}
 }
+

polkadot/runtime/src/lib.rs

@@ -146,7 +146,7 @@ pub type UncheckedExtrinsic = generic::UncheckedExtrinsic<AccountId, Index, Call
 pub type Extrinsic = generic::Extrinsic<AccountId, Index, Call>;
 /// Executive: handles dispatch to the various modules.
 pub type Executive = executive::Executive<Concrete, Block, Staking,
-	((((((), Parachains), Council), Democracy), Staking), Session)>;
+	(((((((), Parachains), Council), Democracy), Staking), Session), Timestamp)>;
 
 impl_outer_config! {
 	pub struct GenesisConfig for Concrete {

polkadot/runtime/src/parachains.rs

@@ -44,7 +44,7 @@ impl<T: Trait> Module<T> {
 	pub fn calculate_duty_roster() -> DutyRoster {
 		let parachain_count = Self::count();
 		let validator_count = <session::Module<T>>::validator_count();
-		let validators_per_parachain = (validator_count - 1) / parachain_count;
+		let validators_per_parachain = if parachain_count != 0 { (validator_count - 1) / parachain_count } else { 0 };
 
 		let mut roles_val = (0..validator_count).map(|i| match i {
 			i if i < parachain_count * validators_per_parachain =>

polkadot/service/Cargo.toml

@@ -7,7 +7,6 @@ authors = ["Parity Technologies <admin@parity.io>"]
 futures = "0.1.17"
 parking_lot = "0.4"
 tokio-timer = "0.1.2"
-hex-literal = "0.1"
 error-chain = "0.11"
 log = "0.4"
 tokio-core = "0.1.12"

polkadot/service/src/lib.rs

@@ -37,8 +37,6 @@ extern crate substrate_executor;
 extern crate tokio_core;
 extern crate substrate_client as client;
 
-#[macro_use]
-extern crate hex_literal;
 #[macro_use]
 extern crate error_chain;
 #[macro_use]
@@ -141,8 +139,12 @@ impl Service {
 		}
 
 		let god_keys = vec![
-			hex!["f09c0d1467d6952c92c343672bfb06a24560f400af8cf98b93df7d40b4efe1b6"],
-			hex!["84718cd2894bcda83beeca3a7842caf269fe93cacde0bdee0e3cbce6de253f0e"]
+			ed25519::Pair::from_seed(b"Alice                           ").public().into(),
+			ed25519::Pair::from_seed(b"Bob                             ").public().into(),
+//			ed25519::Pair::from_seed(b"Charlie                         ").public().into(),
+//			ed25519::Pair::from_seed(b"Dave                            ").public().into(),
+//			ed25519::Pair::from_seed(b"Eve                             ").public().into(),
+//			ed25519::Pair::from_seed(b"Ferdie                          ").public().into(),
 		];
 
 		let genesis_config = GenesisConfig {
@@ -190,15 +192,16 @@ impl Service {
 		let prepare_genesis = || {
 			storage = genesis_config.build_externalities();
 			let block = genesis::construct_genesis_block(&storage);
-			with_externalities(&mut storage, ||
+			with_externalities(&mut storage, || {
 				// TODO: use api.rs to dispatch instead
-				polkadot_runtime::System::initialise_genesis_state(&block.header)
-			);
+				polkadot_runtime::System::initialise_genesis_state(&block.header);
+				info!("Genesis header hash: {}", polkadot_runtime::System::block_hash(0));
+			});
 			(primitives::block::Header::decode(&mut block.header.encode().as_ref()).expect("to_vec() always gives a valid serialisation; qed"), storage.into_iter().collect())
 		};
 
 		let client = Arc::new(client::new_in_mem(executor, prepare_genesis)?);
-		let best_header = client.header(&BlockId::Hash(client.info()?.chain.best_hash))?.expect("Best header always exists; qed");
+		let best_header = client.best_block_header()?;
 		info!("Starting Polkadot. Best block is #{}", best_header.number);
 		let transaction_pool = Arc::new(Mutex::new(TransactionPool::new(config.transaction_pool)));
 		let transaction_pool_adapter = Arc::new(TransactionPoolAdapter {
@@ -220,7 +223,7 @@ impl Service {
 			// Load the first available key. Code above makes sure it exisis.
 			let key = keystore.load(&keystore.contents()?[0], "")?;
 			info!("Using authority key {:?}", key.public());
-			Some(consensus::Service::new(client.clone(), network.clone(), transaction_pool.clone(), key, &best_header))
+			Some(consensus::Service::new(client.clone(), network.clone(), transaction_pool.clone(), key))
 		} else {
 			None
 		};

polkadot/src/main.rs

@@ -22,9 +22,16 @@ extern crate polkadot_cli as cli;
 
 #[macro_use]
 extern crate error_chain;
+extern crate ctrlc;
+
+use std::sync::mpsc;
 
 quick_main!(run);
 
 fn run() -> cli::error::Result<()> {
-	cli::run(::std::env::args())
+	let (exit_send, exit_receive) = mpsc::channel();
+	ctrlc::CtrlC::set_handler(move || {
+		exit_send.send(()).expect("Error sending exit notification");
+	});
+	cli::run(::std::env::args(), exit_receive)
 }

polkadot/transaction-pool/src/lib.rs

@@ -63,8 +63,8 @@ impl PolkadotBlock {
 			return Err(unchecked);
 		}
 		match unchecked.extrinsics[0].extrinsic.function {
-			Call::Timestamp(TimestampCall::set(_)) => return Err(unchecked),
-			_ => {}
+			Call::Timestamp(TimestampCall::set(_)) => {},
+			_ => return Err(unchecked),
 		}
 
 		// any further checks...