[#1794] metrics: Track physical object capacity per shard

Signed-off-by: Pavel Karpy <p.karpy@yadro.com>

pkg/metrics/engine.go

@@ -20,6 +20,7 @@ type (
 		searchDuration                prometheus.Counter
 		listObjectsDuration           prometheus.Counter
 		containerSize                 prometheus.GaugeVec
+		payloadSize                   prometheus.GaugeVec
 	}
 )
 
@@ -110,6 +111,13 @@ func newEngineMetrics() engineMetrics {
 			Name:      "container_size",
 			Help:      "Accumulated size of all objects in a container",
 		}, []string{containerIDLabelKey})
+
+		payloadSize = prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: namespace,
+			Subsystem: engineSubsystem,
+			Name:      "payload_size",
+			Help:      "Accumulated size of all objects in a shard",
+		}, []string{shardIDLabelKey})
 	)
 
 	return engineMetrics{
@@ -125,6 +133,7 @@ func newEngineMetrics() engineMetrics {
 		searchDuration:                searchDuration,
 		listObjectsDuration:           listObjectsDuration,
 		containerSize:                 *containerSize,
+		payloadSize:                   *payloadSize,
 	}
 }
 
@@ -141,6 +150,7 @@ func (m engineMetrics) register() {
 	prometheus.MustRegister(m.searchDuration)
 	prometheus.MustRegister(m.listObjectsDuration)
 	prometheus.MustRegister(m.containerSize)
+	prometheus.MustRegister(m.payloadSize)
 }
 
 func (m engineMetrics) AddListContainersDuration(d time.Duration) {
@@ -190,3 +200,7 @@ func (m engineMetrics) AddListObjectsDuration(d time.Duration) {
 func (m engineMetrics) AddToContainerSize(cnrID string, size int64) {
 	m.containerSize.With(prometheus.Labels{containerIDLabelKey: cnrID}).Add(float64(size))
 }
+
+func (m engineMetrics) AddToPayloadCounter(shardID string, size int64) {
+	m.payloadSize.With(prometheus.Labels{shardIDLabelKey: shardID}).Add(float64(size))
+}