Setup Prometheus metrics (#125)

* setup Prometheus metrics

* expose validator set id

* cargo fmt

* Update beefy-gadget/src/lib.rs

Co-authored-by: Tomasz Drwięga <[email protected]>

* add vote messages gossiped metric

* track authorities change, before checking for MMR root digest

Co-authored-by: Tomasz Drwięga <[email protected]>

client/beefy/Cargo.toml

@@ -13,6 +13,7 @@ parking_lot = "0.11"
 thiserror = "1.0"
 
 codec = { version = "2.0.0", package = "parity-scale-codec", features = ["derive"] }
+prometheus = { package = "substrate-prometheus-endpoint", git = "https://github.com/paritytech/substrate", branch = "master"}
 
 sp-api = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-application-crypto = { git = "https://github.com/paritytech/substrate", branch = "master" }

client/beefy/src/lib.rs

@@ -18,6 +18,8 @@ use std::{convert::TryFrom, fmt::Debug, sync::Arc};
 
 use beefy_primitives::BeefyApi;
 use codec::Codec;
+use log::debug;
+use prometheus::Registry;
 
 use sc_client_api::{Backend, BlockchainEvents, Finalizer};
 use sc_network_gossip::{
@@ -33,6 +35,7 @@ use sp_keystore::SyncCryptoStorePtr;
 use sp_runtime::traits::Block;
 
 mod error;
+mod metrics;
 mod round;
 mod worker;
 
@@ -113,6 +116,7 @@ pub async fn start_beefy_gadget<B, P, BE, C, N, SO>(
 	network: N,
 	signed_commitment_sender: notification::BeefySignedCommitmentSender<B, P::Signature>,
 	_sync_oracle: SO,
+	prometheus_registry: Option<Registry>,
 ) where
 	B: Block,
 	P: sp_core::Pair,
@@ -133,11 +137,26 @@ pub async fn start_beefy_gadget<B, P, BE, C, N, SO>(
 		None,
 	);
 
+	let metrics = prometheus_registry
+		.as_ref()
+		.map(metrics::Metrics::register)
+		.and_then(|result| match result {
+			Ok(metrics) => {
+				debug!(target: "beefy", "🥩 Registered metrics");
+				Some(metrics)
+			}
+			Err(err) => {
+				debug!(target: "beefy", "🥩 Failed to register metrics: {:?}", err);
+				None
+			}
+		});
+
 	let worker = worker::BeefyWorker::<_, P::Signature, _, BE, P>::new(
 		client.clone(),
 		key_store,
 		signed_commitment_sender,
 		gossip_engine,
+		metrics,
 	);
 
 	worker.run().await

client/beefy/src/metrics.rs

@@ -0,0 +1,41 @@
+// Copyright (C) 2020-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program 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.
+
+// This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! BEEFY Prometheus metrics definition
+
+use prometheus::{register, Counter, Gauge, PrometheusError, Registry, U64};
+
+/// BEEFY metrics exposed through Prometheus
+pub(crate) struct Metrics {
+	/// Current active validator set id
+	pub beefy_validator_set_id: Gauge<U64>,
+	pub beefy_gadget_votes: Counter<U64>,
+}
+
+impl Metrics {
+	pub(crate) fn register(registry: &Registry) -> Result<Self, PrometheusError> {
+		Ok(Self {
+			beefy_validator_set_id: register(
+				Gauge::new("beefy_validator_set_id", "Current BEEFY active validator set id.")?,
+				registry,
+			)?,
+			beefy_gadget_votes: register(
+				Counter::new("beefy_gadget_votes_total", "Total number of vote messages gossiped.")?,
+				registry,
+			)?,
+		})
+	}
+}

client/beefy/src/worker.rs

@@ -44,6 +44,7 @@ use sp_runtime::{
 
 use crate::{
 	error::{self},
+	metrics::Metrics,
 	notification, round, Client,
 };
 
@@ -93,6 +94,7 @@ where
 	best_block_voted_on: NumberFor<B>,
 	validator_set_id: ValidatorSetId,
 	client: Arc<C>,
+	metrics: Option<Metrics>,
 	_backend: PhantomData<BE>,
 	_pair: PhantomData<P>,
 }
@@ -121,6 +123,7 @@ where
 		key_store: SyncCryptoStorePtr,
 		signed_commitment_sender: notification::BeefySignedCommitmentSender<B, S>,
 		gossip_engine: GossipEngine<B>,
+		metrics: Option<Metrics>,
 	) -> Self {
 		BeefyWorker {
 			state: State::New,
@@ -135,6 +138,7 @@ where
 			best_block_voted_on: Zero::zero(),
 			validator_set_id: 0,
 			client,
+			metrics,
 			_backend: PhantomData,
 			_pair: PhantomData,
 		}
@@ -240,18 +244,23 @@ where
 				return;
 			};
 
+			if let Some(new) = find_authorities_change::<B, P::Public>(&notification.header) {
+				debug!(target: "beefy", "🥩 New validator set: {:?}", new);
+
+				if let Some(metrics) = self.metrics.as_ref() {
+					metrics.beefy_validator_set_id.set(new.id);
+				}
+
+				self.validator_set_id = new.id;
+			};
+
 			let mmr_root = if let Some(hash) = find_mmr_root_digest::<B, P::Public>(&notification.header) {
 				hash
 			} else {
 				warn!(target: "beefy", "🥩 No MMR root digest found for: {:?}", notification.header.hash());
 				return;
 			};
 
-			if let Some(new) = find_authorities_change::<B, P::Public>(&notification.header) {
-				debug!(target: "beefy", "🥩 New validator set: {:?}", new);
-				self.validator_set_id = new.id;
-			};
-
 			let commitment = Commitment {
 				payload: mmr_root,
 				block_number: notification.header.number(),
@@ -280,6 +289,10 @@ where
 
 			debug!(target: "beefy", "🥩 Sent vote message: {:?}", message);
 
+			if let Some(metrics) = self.metrics.as_ref() {
+				metrics.beefy_gadget_votes.inc();
+			}
+
 			self.handle_vote(
 				(message.commitment.payload, *message.commitment.block_number),
 				(message.id, message.signature),