[statement-distribution] Add metrics for distributed statements in V2 (#4554)

Part of #4334

Author: AndreiEres

polkadot/node/network/statement-distribution/src/lib.rs

@@ -284,7 +284,14 @@ impl<R: rand::Rng> StatementDistributionSubsystem<R> {
 					);
 				},
 				MuxedMessage::Response(result) => {
-					v2::handle_response(&mut ctx, &mut state, result, &mut self.reputation).await;
+					v2::handle_response(
+						&mut ctx,
+						&mut state,
+						result,
+						&mut self.reputation,
+						&self.metrics,
+					)
+					.await;
 				},
 				MuxedMessage::RetryRequest(()) => {
 					// A pending request is ready to retry. This is only a signal to call
@@ -320,7 +327,8 @@ impl<R: rand::Rng> StatementDistributionSubsystem<R> {
 					let mode = prospective_parachains_mode(ctx.sender(), activated.hash).await?;
 					if let ProspectiveParachainsMode::Enabled { .. } = mode {
 						let res =
-							v2::handle_active_leaves_update(ctx, state, activated, mode).await;
+							v2::handle_active_leaves_update(ctx, state, activated, mode, &metrics)
+								.await;
 						// Regardless of the result of leaf activation, we always prune before
 						// handling it to avoid leaks.
 						v2::handle_deactivate_leaves(state, &deactivated);
@@ -370,6 +378,7 @@ impl<R: rand::Rng> StatementDistributionSubsystem<R> {
 							relay_parent,
 							statement,
 							&mut self.reputation,
+							&self.metrics,
 						)
 						.await?;
 					}
@@ -428,11 +437,24 @@ impl<R: rand::Rng> StatementDistributionSubsystem<R> {
 
 					if target.targets_current() {
 						// pass to v2.
-						v2::handle_network_update(ctx, state, event, &mut self.reputation).await;
+						v2::handle_network_update(
+							ctx,
+							state,
+							event,
+							&mut self.reputation,
+							&self.metrics,
+						)
+						.await;
 					}
 				},
 				StatementDistributionMessage::Backed(candidate_hash) => {
-					crate::v2::handle_backed_candidate_message(ctx, state, candidate_hash).await;
+					crate::v2::handle_backed_candidate_message(
+						ctx,
+						state,
+						candidate_hash,
+						&self.metrics,
+					)
+					.await;
 				},
 			},
 		}

polkadot/node/network/statement-distribution/src/metrics.rs

@@ -25,13 +25,13 @@ const HISTOGRAM_LATENCY_BUCKETS: &[f64] = &[
 #[derive(Clone)]
 struct MetricsInner {
 	// V1
-	statements_distributed: prometheus::Counter<prometheus::U64>,
 	sent_requests: prometheus::Counter<prometheus::U64>,
 	received_responses: prometheus::CounterVec<prometheus::U64>,
 	network_bridge_update: prometheus::HistogramVec,
 	statements_unexpected: prometheus::CounterVec<prometheus::U64>,
 	created_message_size: prometheus::Gauge<prometheus::U64>,
 	// V1+
+	statements_distributed: prometheus::Counter<prometheus::U64>,
 	active_leaves_update: prometheus::Histogram,
 	share: prometheus::Histogram,
 	// V2+
@@ -51,6 +51,13 @@ impl Metrics {
 		}
 	}
 
+	/// Update statements distributed counter by an amount
+	pub fn on_statements_distributed(&self, n: usize) {
+		if let Some(metrics) = &self.0 {
+			metrics.statements_distributed.inc_by(n as u64);
+		}
+	}
+
 	/// Update sent requests counter
 	/// This counter is updated merely for the statements sent via request/response method,
 	/// meaning that it counts large statements only