Log validator set changes in EpochManager (#10734)

* Stop breaking out of loop if a non-canonical hash is found

* include expected hash in log msg

* More logging

* Scope

* Syntax

* Log in blank RollingFinality
Escalate bad proposer to warning

* Check validator set size: warn if 1 or even number

* More readable code

* Use SimpleList::new

* Extensive logging on unexpected non-canonical hash

* Wording

* wip

* Update ethcore/blockchain/src/blockchain.rs

Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

* Improved logging, address grumbles

* Update ethcore/src/engines/validator_set/simple_list.rs

Co-Authored-By: Luke Schoen <ltfschoen@users.noreply.github.com>

* Report benign misbehaviour iff currently a validator

* Report malicious behaviour iff we're a validator

* Escalate to warning and fix wording

* Test reporting behaviour
Don't require node to be part of the validator set to report malicious behaviour

* Include missing parent hash in MissingParent error

* Update ethcore/src/engines/validator_set/simple_list.rs

Co-Authored-By: Luke Schoen <ltfschoen@users.noreply.github.com>

* cleanup

* On second thought non-validators are allowed to report

* cleanup

* remove dead code

ethcore/src/engines/authority_round/mod.rs

@@ -235,6 +235,8 @@ impl EpochManager {
 
 		self.force = false;
 		debug!(target: "engine", "Zooming to epoch after block {}", hash);
+		trace!(target: "engine", "Current validator set: {:?}", self.validators());
+
 
 		// epoch_transition_for can be an expensive call, but in the absence of
 		// forks it will only need to be called for the block directly after
@@ -255,7 +257,7 @@ impl EpochManager {
 			let (signal_number, set_proof, _) = destructure_proofs(&last_transition.proof)
 				.expect("proof produced by this engine; therefore it is valid; qed");
 
-			trace!(target: "engine", "extracting epoch set for epoch ({}, {}) signalled at #{}",
+			trace!(target: "engine", "extracting epoch validator set for epoch ({}, {}) signalled at #{}",
 				last_transition.block_number, last_transition.block_hash, signal_number);
 
 			let first = signal_number == 0;
@@ -266,7 +268,12 @@ impl EpochManager {
 				set_proof,
 			)
 				.ok()
-				.map(|(list, _)| list.into_inner())
+				.map(|(list, _)| {
+					trace!(target: "engine", "Updating finality checker with new validator set extracted from epoch ({}, {}): {:?}",
+					       last_transition.block_number, last_transition.block_hash, &list);
+
+					list.into_inner()
+				})
 				.expect("proof produced by this engine; therefore it is valid; qed");
 
 			self.finality_checker = RollingFinality::blank(epoch_set);
@@ -698,7 +705,7 @@ impl AuthorityRound {
 				empty_steps_transition: our_params.empty_steps_transition,
 				maximum_empty_steps: our_params.maximum_empty_steps,
 				strict_empty_steps_transition: our_params.strict_empty_steps_transition,
-				machine: machine,
+				machine,
 			});
 
 		// Do not initialize timeouts for tests.
@@ -729,7 +736,7 @@ impl AuthorityRound {
 
 			if !epoch_manager.zoom_to_after(&*client, &self.machine, &*self.validators, *header.parent_hash()) {
 				debug!(target: "engine", "Unable to zoom to epoch.");
-				return Err(EngineError::MissingParent.into())
+				return Err(EngineError::MissingParent(*header.parent_hash()).into())
 			}
 
 			(CowLike::Owned(epoch_manager.validators().clone()), epoch_manager.epoch_transition_number)
@@ -806,7 +813,7 @@ impl AuthorityRound {
 			return;
 		}
 
-		if let (true, Some(me)) = (current_step > parent_step + 1, self.signer.read().as_ref().map(|s| s.address())) {
+		if let (true, Some(me)) = (current_step > parent_step + 1, self.address()) {
 			debug!(target: "engine", "Author {} built block with step gap. current step: {}, parent step: {}",
 				   header.author(), current_step, parent_step);
 			let mut reported = HashSet::new();
@@ -816,7 +823,11 @@ impl AuthorityRound {
 				if skipped_primary != me {
 					// Stop reporting once validators start repeating.
 					if !reported.insert(skipped_primary) { break; }
+					trace!(target: "engine", "Reporting benign misbehaviour (cause: skipped step) at block #{}, epoch set number {}. Own address: {}",
+						header.number(), set_number, me);
 					self.validators.report_benign(&skipped_primary, set_number, header.number());
+				} else {
+					trace!(target: "engine", "Primary that skipped is self, not self-reporting. Own address: {}", me);
 				}
 			}
 		}
@@ -884,6 +895,10 @@ impl AuthorityRound {
 		let finalized = epoch_manager.finality_checker.push_hash(chain_head.hash(), vec![*chain_head.author()]);
 		finalized.unwrap_or_default()
 	}
+
+	fn address(&self) -> Option<Address> {
+		self.signer.read().as_ref().map(|s| s.address() )
+	}
 }
 
 fn unix_now() -> Duration {
@@ -1283,13 +1298,16 @@ impl Engine<EthereumMachine> for AuthorityRound {
 				// This check runs in Phase 1 where there is no guarantee that the parent block is
 				// already imported, therefore the call to `epoch_set` may fail. In that case we
 				// won't report the misbehavior but this is not a concern because:
-				// - Only authorities can report and it's expected that they'll be up-to-date and
-				//   importing, therefore the parent header will most likely be available
+				// - Authorities will have a signing key available to report and it's expected that
+				//   they'll be up-to-date and importing, therefore the parent header will most likely
+				//   be available
 				// - Even if you are an authority that is syncing the chain, the contract will most
 				//   likely ignore old reports
 				// - This specific check is only relevant if you're importing (since it checks
 				//   against wall clock)
 				if let Ok((_,  set_number)) = self.epoch_set(header) {
+					trace!(target: "engine", "Reporting benign misbehaviour (cause: InvalidSeal) at block #{}, epoch set number {}. Own address: {}",
+						header.number(), set_number, self.address().unwrap_or_default());
 					self.validators.report_benign(header.author(), set_number, header.number());
 				}
 
@@ -1310,7 +1328,7 @@ impl Engine<EthereumMachine> for AuthorityRound {
 		// Ensure header is from the step after parent.
 		if step == parent_step
 			|| (header.number() >= self.validate_step_transition && step <= parent_step) {
-			trace!(target: "engine", "Multiple blocks proposed for step {}.", parent_step);
+			warn!(target: "engine", "Multiple blocks proposed for step {}.", parent_step);
 
 			self.validators.report_malicious(header.author(), set_number, header.number(), Default::default());
 			Err(EngineError::DoubleVote(*header.author()))?;
@@ -1360,6 +1378,8 @@ impl Engine<EthereumMachine> for AuthorityRound {
 			match validate_empty_steps() {
 				Ok(len) => len,
 				Err(err) => {
+					trace!(target: "engine", "Reporting benign misbehaviour (cause: invalid empty steps) at block #{}, epoch set number {}. Own address: {}",
+						header.number(), set_number, self.address().unwrap_or_default());
 					self.validators.report_benign(header.author(), set_number, header.number());
 					return Err(err);
 				},
@@ -1389,6 +1409,8 @@ impl Engine<EthereumMachine> for AuthorityRound {
 		let res = verify_external(header, &*validators, self.empty_steps_transition);
 		match res {
 			Err(Error::Engine(EngineError::NotProposer(_))) => {
+				trace!(target: "engine", "Reporting benign misbehaviour (cause: block from incorrect proposer) at block #{}, epoch set number {}. Own address: {}",
+					header.number(), set_number, self.address().unwrap_or_default());
 				self.validators.report_benign(header.author(), set_number, header.number());
 			},
 			Ok(_) => {
@@ -1619,7 +1641,7 @@ mod tests {
 	use error::Error;
 	use super::{AuthorityRoundParams, AuthorityRound, EmptyStep, SealedEmptyStep, calculate_score};
 
-	fn aura<F>(f: F) -> Arc<AuthorityRound> where
+	fn build_aura<F>(f: F) -> Arc<AuthorityRound> where
 		F: FnOnce(&mut AuthorityRoundParams),
 	{
 		let mut params = AuthorityRoundParams {
@@ -1641,7 +1663,6 @@ mod tests {
 
 		// mutate aura params
 		f(&mut params);
-
 		// create engine
 		let mut c_params = ::spec::CommonParams::default();
 		c_params.gas_limit_bound_divisor = 5.into();
@@ -1821,9 +1842,19 @@ mod tests {
 
 	#[test]
 	fn reports_skipped() {
+		let _ = ::env_logger::try_init();
+
+		let validator1 = Address::from_low_u64_be(1);
+		let validator2 = Address::from_low_u64_be(2);
 		let last_benign = Arc::new(AtomicUsize::new(0));
-		let aura = aura(|p| {
-			p.validators = Box::new(TestSet::new(Default::default(), last_benign.clone()));
+
+		let aura = build_aura(|p| {
+			let validator_set = TestSet::new(
+				Default::default(),
+				last_benign.clone(),
+				vec![validator1, validator2],
+			);
+			p.validators = Box::new(validator_set);
 		});
 
 		let mut parent_header: Header = Header::default();
@@ -1838,7 +1869,11 @@ mod tests {
 		assert!(aura.verify_block_family(&header, &parent_header).is_ok());
 		assert_eq!(last_benign.load(AtomicOrdering::SeqCst), 0);
 
-		aura.set_signer(Box::new((Arc::new(AccountProvider::transient_provider()), Default::default(), "".into())));
+		aura.set_signer(Box::new((
+			Arc::new(AccountProvider::transient_provider()),
+			validator2,
+			"".into(),
+		)));
 
 		// Do not report on steps skipped between genesis and first block.
 		header.set_number(1);
@@ -1853,7 +1888,7 @@ mod tests {
 
 	#[test]
 	fn test_uncles_transition() {
-		let aura = aura(|params| {
+		let aura = build_aura(|params| {
 			params.maximum_uncle_count_transition = 1;
 		});
 
@@ -1889,7 +1924,7 @@ mod tests {
 	#[test]
 	#[should_panic(expected="authority_round: step duration can't be zero")]
 	fn test_step_duration_zero() {
-		aura(|params| {
+		build_aura(|params| {
 			params.step_duration = 0;
 		});
 	}
@@ -2281,7 +2316,7 @@ mod tests {
 
 	#[test]
 	fn test_empty_steps() {
-		let engine = aura(|p| {
+		let engine = build_aura(|p| {
 			p.step_duration = 4;
 			p.empty_steps_transition = 0;
 			p.maximum_empty_steps = 0;
@@ -2314,7 +2349,7 @@ mod tests {
 	fn should_reject_duplicate_empty_steps() {
 		// given
 		let (_spec, tap, accounts) = setup_empty_steps();
-		let engine = aura(|p| {
+		let engine = build_aura(|p| {
 			p.validators = Box::new(SimpleList::new(accounts.clone()));
 			p.step_duration = 4;
 			p.empty_steps_transition = 0;
@@ -2351,7 +2386,7 @@ mod tests {
 	fn should_reject_empty_steps_out_of_order() {
 		// given
 		let (_spec, tap, accounts) = setup_empty_steps();
-		let engine = aura(|p| {
+		let engine = build_aura(|p| {
 			p.validators = Box::new(SimpleList::new(accounts.clone()));
 			p.step_duration = 4;
 			p.empty_steps_transition = 0;

ethcore/src/engines/mod.rs

@@ -90,7 +90,7 @@ pub enum EngineError {
 	/// Requires signer ref, but none registered.
 	RequiresSigner,
 	/// Missing Parent Epoch
-	MissingParent,
+	MissingParent(H256),
 	/// Checkpoint is missing
 	CliqueMissingCheckpoint(H256),
 	/// Missing vanity data
@@ -139,7 +139,7 @@ impl fmt::Display for EngineError {
 			RequiresClient => format!("Call requires client but none registered"),
 			RequiresSigner => format!("Call requires signer but none registered"),
 			InvalidEngine => format!("Invalid engine specification or implementation"),
-			MissingParent => format!("Parent Epoch is missing from database"),
+			MissingParent(ref hash) => format!("Parent Epoch is missing from database: {}", hash),
 		};
 
 		f.write_fmt(format_args!("Engine error ({})", msg))

ethcore/src/engines/validator_set/simple_list.rs

@@ -36,9 +36,8 @@ impl SimpleList {
 		let validator_count = validators.len();
 		if validator_count == 1 {
 			warn!(target: "engine", "Running AuRa with a single validator implies instant finality. Use a database?");
-		}
-		if validator_count % 2 == 0 {
-			warn!(target: "engine", "Running AuRa with an even number of validators is not recommended (risk of network split).");
+		} else if validator_count != 0 && validator_count % 2 == 0 {
+			warn!(target: "engine", "Running AuRa with an even number of validators ({}) is not recommended (risk of network split).", validator_count);
 		}
 		SimpleList { validators }
 	}

ethcore/src/engines/validator_set/test.rs

@@ -30,7 +30,7 @@ use machine::{AuxiliaryData, Call, EthereumMachine};
 use super::{ValidatorSet, SimpleList};
 
 /// Set used for testing with a single validator.
-#[derive(MallocSizeOf)]
+#[derive(MallocSizeOf, Debug)]
 pub struct TestSet {
 	validator: SimpleList,
 	#[ignore_malloc_size_of = "zero sized"]
@@ -41,14 +41,18 @@ pub struct TestSet {
 
 impl Default for TestSet {
 	fn default() -> Self {
-		TestSet::new(Default::default(), Default::default())
+		TestSet::new(
+			Default::default(),
+			Default::default(),
+			vec![Address::from_str("7d577a597b2742b498cb5cf0c26cdcd726d39e6e").unwrap()]
+		)
 	}
 }
 
 impl TestSet {
-	pub fn new(last_malicious: Arc<AtomicUsize>, last_benign: Arc<AtomicUsize>) -> Self {
+	pub fn new(last_malicious: Arc<AtomicUsize>, last_benign: Arc<AtomicUsize>, validators: Vec<Address>) -> Self {
 		TestSet {
-			validator: SimpleList::new(vec![Address::from_str("7d577a597b2742b498cb5cf0c26cdcd726d39e6e").unwrap()]),
+			validator: SimpleList::new(validators),
 			last_malicious,
 			last_benign,
 		}