Add more metrics to prometheus (#5034)

* Add a few things

* Add finality_grandpa_round

* fix fg tests

* Nitpicks

* Nitpicks

* Fix name of prometheus crate

substrate/client/finality-grandpa/Cargo.toml

@@ -35,6 +35,7 @@ sc-network = { version = "0.8.0-alpha.2", path = "../network" }
 sc-network-gossip = { version = "0.8.0-alpha.2", path = "../network-gossip" }
 sp-finality-tracker = { version = "2.0.0-alpha.2", path = "../../primitives/finality-tracker" }
 sp-finality-grandpa = { version = "2.0.0-alpha.2", path = "../../primitives/finality-grandpa" }
+prometheus-endpoint = { package = "substrate-prometheus-endpoint", path = "../../utils/prometheus", version = "0.8.0-alpha.2" }
 sc-block-builder = { version = "0.8.0-alpha.2", path = "../block-builder" }
 finality-grandpa = { version = "0.11.1", features = ["derive-codec"] }
 pin-project = "0.4.6"

substrate/client/finality-grandpa/src/environment.rs

@@ -58,6 +58,7 @@ use crate::justification::GrandpaJustification;
 use crate::until_imported::UntilVoteTargetImported;
 use crate::voting_rule::VotingRule;
 use sp_finality_grandpa::{AuthorityId, AuthoritySignature, SetId, RoundNumber};
+use prometheus_endpoint::{Gauge, U64, register, PrometheusError};
 
 type HistoricalVotes<Block> = finality_grandpa::HistoricalVotes<
 	<Block as BlockT>::Hash,
@@ -372,6 +373,24 @@ impl<Block: BlockT> SharedVoterSetState<Block> {
 	}
 }
 
+/// Prometheus metrics for GRANDPA.
+#[derive(Clone)]
+pub(crate) struct Metrics {
+	finality_grandpa_round: Gauge<U64>,
+}
+
+impl Metrics {
+	pub(crate) fn register(registry: &prometheus_endpoint::Registry) -> Result<Self, PrometheusError> {
+		Ok(Self {
+			finality_grandpa_round: register(
+				Gauge::new("finality_grandpa_round", "Highest completed GRANDPA round.")?,
+				registry
+			)?,
+		})
+	}
+}
+
+
 /// The environment we run GRANDPA in.
 pub(crate) struct Environment<Backend, Block: BlockT, C, N: NetworkT<Block>, SC, VR> {
 	pub(crate) client: Arc<C>,
@@ -384,6 +403,7 @@ pub(crate) struct Environment<Backend, Block: BlockT, C, N: NetworkT<Block>, SC,
 	pub(crate) set_id: SetId,
 	pub(crate) voter_set_state: SharedVoterSetState<Block>,
 	pub(crate) voting_rule: VR,
+	pub(crate) metrics: Option<Metrics>,
 	pub(crate) _phantom: PhantomData<Backend>,
 }
 
@@ -397,6 +417,17 @@ impl<Backend, Block: BlockT, C, N: NetworkT<Block>, SC, VR> Environment<Backend,
 		self.voter_set_state.with(|voter_set_state| {
 			if let Some(set_state) = f(&voter_set_state)? {
 				*voter_set_state = set_state;
+
+				if let Some(metrics) = self.metrics.as_ref() {
+					if let VoterSetState::Live { completed_rounds, .. } = voter_set_state {
+						let highest = completed_rounds.rounds.iter()
+							.map(|round| round.number)
+							.max()
+							.expect("There is always one completed round (genesis); qed");
+
+						metrics.finality_grandpa_round.set(highest);
+					}
+				}
 			}
 			Ok(())
 		})

substrate/client/finality-grandpa/src/lib.rs

@@ -104,7 +104,7 @@ pub use voting_rule::{
 };
 
 use aux_schema::PersistentData;
-use environment::{Environment, VoterSetState};
+use environment::{Environment, VoterSetState, Metrics};
 use import::GrandpaBlockImport;
 use until_imported::UntilGlobalMessageBlocksImported;
 use communication::{NetworkBridge, Network as NetworkT};
@@ -551,6 +551,8 @@ pub struct GrandpaParams<Block: BlockT, C, N, SC, VR, X> {
 	pub telemetry_on_connect: Option<futures::channel::mpsc::UnboundedReceiver<()>>,
 	/// A voting rule used to potentially restrict target votes.
 	pub voting_rule: VR,
+	/// The prometheus metrics registry.
+	pub prometheus_registry: Option<prometheus_endpoint::Registry>,
 }
 
 /// Run a GRANDPA voter as a task. Provide configuration and a link to a
@@ -576,6 +578,7 @@ pub fn run_grandpa_voter<Block: BlockT, BE: 'static, C, N, SC, VR, X>(
 		on_exit,
 		telemetry_on_connect,
 		voting_rule,
+		prometheus_registry,
 	} = grandpa_params;
 
 	// NOTE: we have recently removed `run_grandpa_observer` from the public
@@ -634,6 +637,7 @@ pub fn run_grandpa_voter<Block: BlockT, BE: 'static, C, N, SC, VR, X>(
 		voting_rule,
 		persistent_data,
 		voter_commands_rx,
+		prometheus_registry,
 	);
 
 	let voter_work = voter_work
@@ -673,6 +677,7 @@ where
 		voting_rule: VR,
 		persistent_data: PersistentData<Block>,
 		voter_commands_rx: mpsc::UnboundedReceiver<VoterCommand<Block::Hash, NumberFor<Block>>>,
+		prometheus_registry: Option<prometheus_endpoint::Registry>,
 	) -> Self {
 
 		let voters = persistent_data.authority_set.current_authorities();
@@ -687,6 +692,10 @@ where
 			authority_set: persistent_data.authority_set.clone(),
 			consensus_changes: persistent_data.consensus_changes.clone(),
 			voter_set_state: persistent_data.set_state.clone(),
+			metrics: prometheus_registry.map(|registry| {
+				Metrics::register(&registry)
+					.expect("Other metrics would have failed to register before these; qed")
+			}),
 			_phantom: PhantomData,
 		});
 
@@ -807,6 +816,7 @@ where
 					consensus_changes: self.env.consensus_changes.clone(),
 					network: self.env.network.clone(),
 					voting_rule: self.env.voting_rule.clone(),
+					metrics: self.env.metrics.clone(),
 					_phantom: PhantomData,
 				});
 

substrate/client/finality-grandpa/src/tests.rs

@@ -447,6 +447,7 @@ fn run_to_completion_with<F>(
 			on_exit: Exit,
 			telemetry_on_connect: None,
 			voting_rule: (),
+			prometheus_registry: None,
 		};
 		let voter = run_grandpa_voter(grandpa_params).expect("all in order with client and network");
 
@@ -578,6 +579,7 @@ fn finalize_3_voters_1_full_observer() {
 			on_exit: Exit,
 			telemetry_on_connect: None,
 			voting_rule: (),
+			prometheus_registry: None,
 		};
 
 		voters.push(run_grandpa_voter(grandpa_params).expect("all in order with client and network"));
@@ -741,6 +743,7 @@ fn transition_3_voters_twice_1_full_observer() {
 			on_exit: Exit,
 			telemetry_on_connect: None,
 			voting_rule: (),
+			prometheus_registry: None,
 		};
 		let voter = run_grandpa_voter(grandpa_params).expect("all in order with client and network");
 
@@ -1166,6 +1169,7 @@ fn voter_persists_its_votes() {
 							on_exit: Exit,
 							telemetry_on_connect: None,
 							voting_rule: VotingRulesBuilder::default().build(),
+							prometheus_registry: None,
 						};
 
 						let voter = run_grandpa_voter(grandpa_params)
@@ -1511,6 +1515,7 @@ fn voter_catches_up_to_latest_round_when_behind() {
 			on_exit: Exit,
 			telemetry_on_connect: None,
 			voting_rule: (),
+			prometheus_registry: None,
 		};
 
 		Box::pin(run_grandpa_voter(grandpa_params).expect("all in order with client and network"))
@@ -1642,6 +1647,7 @@ fn grandpa_environment_respects_voting_rules() {
 			voters: Arc::new(authority_set.current_authorities()),
 			network,
 			voting_rule,
+			metrics: None,
 			_phantom: PhantomData,
 		}
 	};