[#370] Add tree service metrics

Signed-off-by: Alejandro Lopez <a.lopez@yadro.com>

pkg/services/tree/sync.go

@@ -9,6 +9,7 @@ import (
 	"math"
 	"math/rand"
 	"sync"
+	"time"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/pkg/tracing"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/internal/logs"
@@ -376,9 +377,12 @@ func (s *Service) syncLoop(ctx context.Context) {
 			ctx, span := tracing.StartSpanFromContext(ctx, "TreeService.sync")
 			s.log.Debug(logs.TreeSyncingTrees)
 
+			start := time.Now()
+
 			cnrs, err := s.cfg.cnrSource.List()
 			if err != nil {
 				s.log.Error(logs.TreeCouldNotFetchContainers, zap.Error(err))
+				s.metrics.AddSyncDuration(time.Since(start), false)
 				span.End()
 				continue
 			}
@@ -390,6 +394,8 @@ func (s *Service) syncLoop(ctx context.Context) {
 			s.removeContainers(ctx, newMap)
 
 			s.log.Debug(logs.TreeTreesHaveBeenSynchronized)
+
+			s.metrics.AddSyncDuration(time.Since(start), true)
 			span.End()
 		}
 	}