From d33e11b52c61f007aac8f1c936f479060f4941db Mon Sep 17 00:00:00 2001
From: Viacheslav Gonkivskyi <viacheslavgonkivskyi@gmail.com>
Date: Wed, 10 Jan 2024 13:39:06 +0200
Subject: [PATCH] chore: unregister metrics on stop

---
 sync/metrics.go   | 11 +++++++++--
 sync/sync.go      |  4 ++--
 sync/sync_head.go |  2 +-
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/sync/metrics.go b/sync/metrics.go
index 32b29f12..e6f01984 100644
--- a/sync/metrics.go
+++ b/sync/metrics.go
@@ -122,13 +122,13 @@ func (m *metrics) recordTotalSynced(totalSynced int) {
 	})
 }
 
-func (m *metrics) recordSyncLoopStarted(ctx context.Context) {
+func (m *metrics) syncingStarted(ctx context.Context) {
 	m.observe(ctx, func(ctx context.Context) {
 		m.syncLoopStarted.Add(ctx, 1)
 	})
 }
 
-func (m *metrics) recordTrustedPeersOutOfSync(ctx context.Context) {
+func (m *metrics) peersOutOufSync(ctx context.Context) {
 	m.observe(ctx, func(ctx context.Context) {
 		m.trustedPeersOutOfSync.Add(ctx, 1)
 	})
@@ -159,3 +159,10 @@ func (m *metrics) observe(ctx context.Context, observeFn func(context.Context))
 	}
 	observeFn(ctx)
 }
+
+func (m *metrics) Close() error {
+	if m == nil {
+		return nil
+	}
+	return m.syncReg.Unregister()
+}
diff --git a/sync/sync.go b/sync/sync.go
index 46472c28..e41a304b 100644
--- a/sync/sync.go
+++ b/sync/sync.go
@@ -109,7 +109,7 @@ func (s *Syncer[H]) Start(ctx context.Context) error {
 // Stop stops Syncer.
 func (s *Syncer[H]) Stop(context.Context) error {
 	s.cancel()
-	return nil
+	return s.metrics.Close()
 }
 
 // SyncWait blocks until ongoing sync is done.
@@ -180,7 +180,7 @@ func (s *Syncer[H]) syncLoop() {
 	for {
 		select {
 		case <-s.triggerSync:
-			s.metrics.recordSyncLoopStarted(s.ctx)
+			s.metrics.syncingStarted(s.ctx)
 			s.sync(s.ctx)
 		case <-s.ctx.Done():
 			return
diff --git a/sync/sync_head.go b/sync/sync_head.go
index 31a42691..02868543 100644
--- a/sync/sync_head.go
+++ b/sync/sync_head.go
@@ -102,7 +102,7 @@ func (s *Syncer[H]) subjectiveHead(ctx context.Context) (H, error) {
 		log.Warnw("subjective initialization with an old header", "height", trustHead.Height())
 	}
 	log.Warn("trusted peer is out of sync")
-	s.metrics.recordTrustedPeersOutOfSync(s.ctx)
+	s.metrics.peersOutOufSync(s.ctx)
 	return trustHead, nil
 }