grandpa: filter some telemetry events on larger voter sets (#4700)

substrate/client/finality-grandpa/src/communication/mod.rs

@@ -106,6 +106,11 @@ mod benefit {
 	pub(super) const PER_EQUIVOCATION: i32 = 10;
 }
 
+/// If the voter set is larger than this value some telemetry events are not
+/// sent to avoid increasing usage resource on the node and flooding the
+/// telemetry server (e.g. received votes, received commits.)
+const TELEMETRY_VOTERS_LIMIT: usize = 10;
+
 /// A handle to the network.
 ///
 /// Something that provides both the capabilities needed for the `gossip_network::Network` trait as
@@ -308,6 +313,7 @@ impl<B: BlockT, N: Network<B>> NetworkBridge<B, N> {
 							return Ok(None);
 						}
 
+						if voters.len() <= TELEMETRY_VOTERS_LIMIT {
 							match &msg.message.message {
 								PrimaryPropose(propose) => {
 									telemetry!(CONSENSUS_INFO; "afg.received_propose";
@@ -331,6 +337,7 @@ impl<B: BlockT, N: Network<B>> NetworkBridge<B, N> {
 									);
 								},
 							};
+						}
 
 						Ok(Some(msg.message))
 					}
@@ -474,11 +481,13 @@ fn incoming_global<B: BlockT>(
 				format!("{}", a)
 			}).collect();
 
+		if voters.len() <= TELEMETRY_VOTERS_LIMIT {
 			telemetry!(CONSENSUS_INFO; "afg.received_commit";
 				"contains_precommits_signed_by" => ?precommits_signed_by,
 				"target_number" => ?msg.message.target_number.clone(),
 				"target_hash" => ?msg.message.target_hash.clone(),
 			);
+		}
 
 		if let Err(cost) = check_compact_commit::<B>(
 			&msg.message,