From 324e51fbbf842ab1561ef882ef7c21eb47bebd53 Mon Sep 17 00:00:00 2001
From: Max Inden <mail@max-inden.de>
Date: Fri, 24 Apr 2020 17:40:48 +0200
Subject: [PATCH] client/authority-discovery: Reduce log level replaced by
 metrics

Instead of logging value-found-event-handling failures or value-put
failures on error level, log them on debug level only additionally
recording them via Prometheus.

Motivation is that both events can happen in "normal" operations and
thus clutter the logs.
---
 .../client/authority-discovery/src/lib.rs      | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/substrate/client/authority-discovery/src/lib.rs b/substrate/client/authority-discovery/src/lib.rs
index 91e8293dec..e5b7c986a4 100644
--- a/substrate/client/authority-discovery/src/lib.rs
+++ b/substrate/client/authority-discovery/src/lib.rs
@@ -60,7 +60,7 @@ use futures_timer::Delay;
 
 use codec::{Decode, Encode};
 use error::{Error, Result};
-use log::{debug, error, log_enabled, warn};
+use log::{debug, error, log_enabled};
 use prometheus_endpoint::{Counter, CounterVec, Gauge, Opts, U64, register};
 use prost::Message;
 use sc_client_api::blockchain::HeaderBackend;
@@ -328,7 +328,11 @@ where
 					}
 
 					if let Err(e) = self.handle_dht_value_found_event(v) {
-						error!(
+						if let Some(metrics) = &self.metrics {
+							metrics.handle_value_found_event_failure.inc();
+						}
+
+						debug!(
 							target: LOG_TARGET,
 							"Failed to handle Dht value found event: {:?}", e,
 						);
@@ -359,7 +363,7 @@ where
 						metrics.dht_event_received.with_label_values(&["value_put_failed"]).inc();
 					}
 
-					warn!(
+					debug!(
 						target: LOG_TARGET,
 						"Failed to put hash '{:?}' on Dht.", hash
 					)
@@ -603,6 +607,7 @@ pub(crate) struct Metrics {
 	amount_last_published: Gauge<U64>,
 	request: Counter<U64>,
 	dht_event_received: CounterVec<U64>,
+	handle_value_found_event_failure: Counter<U64>,
 	priority_group_size: Gauge<U64>,
 }
 
@@ -642,6 +647,13 @@ impl Metrics {
 				)?,
 				registry,
 			)?,
+			handle_value_found_event_failure: register(
+				Counter::new(
+					"authority_discovery_handle_value_found_event_failure",
+					"Number of times handling a dht value found event failed."
+				)?,
+				registry,
+			)?,
 			priority_group_size: register(
 				Gauge::new(
 					"authority_discovery_priority_group_size",