Reactive syncing metrics

prdoc/pr_5410.prdoc

@@ -0,0 +1,11 @@
+title: Reactive syncing metrics
+
+doc:
+  - audience: Node Dev
+    description: |
+      Syncing metrics are now updated immediate as changes happen rather than every 1100ms as it was happening before.
+      This resulted in minor, but breaking API changes.
+
+crates:
+  - name: sc-network-sync
+    bump: major

substrate/client/network/sync/Cargo.toml

@@ -33,7 +33,7 @@ schnellru = { workspace = true }
 smallvec = { workspace = true, default-features = true }
 thiserror = { workspace = true }
 tokio-stream = { workspace = true }
-tokio = { features = ["macros", "time"], workspace = true, default-features = true }
+tokio = { features = ["macros"], workspace = true, default-features = true }
 fork-tree = { workspace = true, default-features = true }
 prometheus-endpoint = { workspace = true, default-features = true }
 sc-client-api = { workspace = true, default-features = true }

substrate/client/network/sync/src/engine.rs

@@ -54,7 +54,6 @@ use prometheus_endpoint::{
 };
 use prost::Message;
 use schnellru::{ByLength, LruMap};
-use tokio::time::{Interval, MissedTickBehavior};
 
 use sc_client_api::{BlockBackend, HeaderBackend, ProofProvider};
 use sc_consensus::{import_queue::ImportQueueService, IncomingBlock};
@@ -93,9 +92,6 @@ use std::{
 	},
 };
 
-/// Interval at which we perform time based maintenance
-const TICK_TIMEOUT: std::time::Duration = std::time::Duration::from_millis(1100);
-
 /// Maximum number of known block hashes to keep for a peer.
 const MAX_KNOWN_BLOCKS: usize = 1024; // ~32kb per peer + LruHashSet overhead
 
@@ -219,9 +215,6 @@ pub struct SyncingEngine<B: BlockT, Client> {
 	/// Set of channels for other protocols that have subscribed to syncing events.
 	event_streams: Vec<TracingUnboundedSender<SyncEvent>>,
 
-	/// Interval at which we call `tick`.
-	tick_timeout: Interval,
-
 	/// All connected peers. Contains both full and light node peers.
 	peers: HashMap<PeerId, Peer<B>>,
 
@@ -436,12 +429,6 @@ where
 		let max_out_peers = net_config.network_config.default_peers_set.out_peers;
 		let max_in_peers = (max_full_peers - max_out_peers) as usize;
 
-		let tick_timeout = {
-			let mut interval = tokio::time::interval(TICK_TIMEOUT);
-			interval.set_missed_tick_behavior(MissedTickBehavior::Delay);
-			interval
-		};
-
 		Ok((
 			Self {
 				roles,
@@ -469,7 +456,6 @@ where
 				max_in_peers,
 				event_streams: Vec::new(),
 				notification_service,
-				tick_timeout,
 				peer_store_handle,
 				metrics: if let Some(r) = metrics_registry {
 					match Metrics::register(r, is_major_syncing.clone()) {
@@ -493,15 +479,6 @@ where
 		))
 	}
 
-	/// Report Prometheus metrics.
-	pub fn report_metrics(&self) {
-		if let Some(metrics) = &self.metrics {
-			let n = u64::try_from(self.peers.len()).unwrap_or(std::u64::MAX);
-			metrics.peers.set(n);
-		}
-		self.strategy.report_metrics();
-	}
-
 	fn update_peer_info(
 		&mut self,
 		peer_id: &PeerId,
@@ -628,7 +605,6 @@ where
 	pub async fn run(mut self) {
 		loop {
 			tokio::select! {
-				_ = self.tick_timeout.tick() => self.perform_periodic_actions(),
 				command = self.service_rx.select_next_some() =>
 					self.process_service_command(command),
 				notification_event = self.notification_service.next_event() => match notification_event {
@@ -757,10 +733,6 @@ where
 		Ok(())
 	}
 
-	fn perform_periodic_actions(&mut self) {
-		self.report_metrics();
-	}
-
 	fn process_service_command(&mut self, command: ToServiceCommand<B>) {
 		match command {
 			ToServiceCommand::SetSyncForkRequest(peers, hash, number) => {
@@ -922,6 +894,9 @@ where
 			log::debug!(target: LOG_TARGET, "{peer_id} does not exist in `SyncingEngine`");
 			return
 		};
+		if let Some(metrics) = &self.metrics {
+			metrics.peers.dec();
+		}
 
 		if self.important_peers.contains(&peer_id) {
 			log::warn!(target: LOG_TARGET, "Reserved peer {peer_id} disconnected");
@@ -1097,7 +1072,11 @@ where
 
 		log::debug!(target: LOG_TARGET, "Connected {peer_id}");
 
-		self.peers.insert(peer_id, peer);
+		if self.peers.insert(peer_id, peer).is_none() {
+			if let Some(metrics) = &self.metrics {
+				metrics.peers.inc();
+			}
+		}
 		self.peer_store_handle.set_peer_role(&peer_id, status.roles.into());
 
 		if self.default_peers_set_no_slot_peers.contains(&peer_id) {