[#1653] qos: Add metrics

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

internal/metrics/qos.go

@@ -0,0 +1,52 @@
+package metrics
+
+import (
+	"git.frostfs.info/TrueCloudLab/frostfs-observability/metrics"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+type QoSMetrics struct {
+	opsCounter *prometheus.GaugeVec
+}
+
+func newQoSMetrics() *QoSMetrics {
+	return &QoSMetrics{
+		opsCounter: metrics.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: namespace,
+			Subsystem: qosSubsystem,
+			Name:      "operations_total",
+			Help:      "Count of pending, in progree, completed and failed due of resource exhausted error operations for each shard",
+		}, []string{shardIDLabel, operationLabel, ioTagLabel, typeLabel}),
+	}
+}
+
+func (m *QoSMetrics) SetOperationTagCounters(shardID, operation, tag string, pending, inProgress, completed, resourceExhausted uint64) {
+	m.opsCounter.With(prometheus.Labels{
+		shardIDLabel:   shardID,
+		operationLabel: operation,
+		ioTagLabel:     tag,
+		typeLabel:      "pending",
+	}).Set(float64(pending))
+	m.opsCounter.With(prometheus.Labels{
+		shardIDLabel:   shardID,
+		operationLabel: operation,
+		ioTagLabel:     tag,
+		typeLabel:      "in_progress",
+	}).Set(float64(inProgress))
+	m.opsCounter.With(prometheus.Labels{
+		shardIDLabel:   shardID,
+		operationLabel: operation,
+		ioTagLabel:     tag,
+		typeLabel:      "completed",
+	}).Set(float64(completed))
+	m.opsCounter.With(prometheus.Labels{
+		shardIDLabel:   shardID,
+		operationLabel: operation,
+		ioTagLabel:     tag,
+		typeLabel:      "resource_exhausted",
+	}).Set(float64(resourceExhausted))
+}
+
+func (m *QoSMetrics) Close(shardID string) {
+	m.opsCounter.DeletePartialMatch(prometheus.Labels{shardIDLabel: shardID})
+}