[#602] metrics: Add blobovnicza items counter

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/metrics/blobovnicza.go

@@ -18,6 +18,9 @@ type BlobobvnizcaMetrics interface {
 	AddOpenBlobovniczaSize(shardID, path string, size uint64)
 	SubOpenBlobovniczaSize(shardID, path string, size uint64)
 
+	AddOpenBlobovniczaItems(shardID, path string, items uint64)
+	SubOpenBlobovniczaItems(shardID, path string, items uint64)
+
 	IncOpenBlobovniczaCount(shardID, path string)
 	DecOpenBlobovniczaCount(shardID, path string)
 }
@@ -28,6 +31,7 @@ type blobovnicza struct {
 	treePut         *prometheus.CounterVec
 	treeGet         *prometheus.CounterVec
 	treeOpenSize    *prometheus.GaugeVec
+	treeOpenItems   *prometheus.GaugeVec
 	treeOpenCounter *prometheus.GaugeVec
 }
 
@@ -59,6 +63,12 @@ func newBlobovnicza() *blobovnicza {
 			Name:      "open_blobovnicza_size_bytes",
 			Help:      "Size of opened blobovniczas of Blobovnicza tree",
 		}, []string{shardIDLabel, pathLabel}),
+		treeOpenItems: metrics.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: namespace,
+			Subsystem: blobovniczaTreeSubSystem,
+			Name:      "open_blobovnicza_items_total",
+			Help:      "Count of items in opened blobovniczas of Blobovnicza tree",
+		}, []string{shardIDLabel, pathLabel}),
 		treeOpenCounter: metrics.NewGaugeVec(prometheus.GaugeOpts{
 			Namespace: namespace,
 			Subsystem: blobovniczaTreeSubSystem,
@@ -139,3 +149,17 @@ func (b *blobovnicza) DecOpenBlobovniczaCount(shardID, path string) {
 		pathLabel:    path,
 	}).Dec()
 }
+
+func (b *blobovnicza) AddOpenBlobovniczaItems(shardID, path string, items uint64) {
+	b.treeOpenItems.With(prometheus.Labels{
+		shardIDLabel: shardID,
+		pathLabel:    path,
+	}).Add(float64(items))
+}
+
+func (b *blobovnicza) SubOpenBlobovniczaItems(shardID, path string, items uint64) {
+	b.treeOpenItems.With(prometheus.Labels{
+		shardIDLabel: shardID,
+		pathLabel:    path,
+	}).Sub(float64(items))
+}