[#373] metrics: Add FSTree metrics

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

pkg/metrics/fstree.go

@@ -0,0 +1,96 @@
+package metrics
+
+import (
+	"strconv"
+	"time"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-observability/metrics"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+type FSTreeMetrics interface {
+	SetMode(shardID, path string, readOnly bool)
+	Close(shardID, path string)
+
+	MethodDuration(shardID, path string, method string, d time.Duration, success bool)
+	AddGet(shardID, path string, size int)
+	AddPut(shardID, path string, size int)
+}
+
+type fstreeMetrics struct {
+	mode        *shardIDPathModeValue
+	reqDuration *prometheus.HistogramVec
+	put         *prometheus.CounterVec
+	get         *prometheus.CounterVec
+}
+
+func newFSTreeMetrics() *fstreeMetrics {
+	return &fstreeMetrics{
+		mode: newShardIDPathMode(fstreeSubSystem, "mode", "FSTree mode value"),
+		reqDuration: metrics.NewHistogramVec(prometheus.HistogramOpts{
+			Namespace: namespace,
+			Subsystem: fstreeSubSystem,
+			Name:      "request_duration_seconds",
+			Help:      "Accumulated FSTree request process duration",
+		}, []string{shardIDLabel, successLabel, pathLabel, methodLabel}),
+		put: metrics.NewCounterVec(prometheus.CounterOpts{
+			Namespace: namespace,
+			Subsystem: fstreeSubSystem,
+			Name:      "put_bytes",
+			Help:      "Accumulated payload size written to FSTree",
+		}, []string{shardIDLabel, pathLabel}),
+		get: metrics.NewCounterVec(prometheus.CounterOpts{
+			Namespace: namespace,
+			Subsystem: fstreeSubSystem,
+			Name:      "get_bytes",
+			Help:      "Accumulated payload size read from FSTree",
+		}, []string{shardIDLabel, pathLabel}),
+	}
+}
+
+func (m *fstreeMetrics) SetMode(shardID, path string, readOnly bool) {
+	modeValue := readWriteMode
+	if readOnly {
+		modeValue = readOnlyMode
+	}
+	m.mode.SetMode(shardID, path, modeValue)
+}
+
+func (m *fstreeMetrics) Close(shardID, path string) {
+	m.mode.SetMode(shardID, path, closedMode)
+	m.reqDuration.DeletePartialMatch(prometheus.Labels{
+		shardIDLabel: shardID,
+		pathLabel:    path,
+	})
+	m.get.DeletePartialMatch(prometheus.Labels{
+		shardIDLabel: shardID,
+		pathLabel:    path,
+	})
+	m.put.DeletePartialMatch(prometheus.Labels{
+		shardIDLabel: shardID,
+		pathLabel:    path,
+	})
+}
+
+func (m *fstreeMetrics) MethodDuration(shardID, path string, method string, d time.Duration, success bool) {
+	m.reqDuration.With(prometheus.Labels{
+		shardIDLabel: shardID,
+		pathLabel:    path,
+		successLabel: strconv.FormatBool(success),
+		methodLabel:  method,
+	}).Observe(d.Seconds())
+}
+
+func (m *fstreeMetrics) AddGet(shardID, path string, size int) {
+	m.get.With(prometheus.Labels{
+		shardIDLabel: shardID,
+		pathLabel:    path,
+	}).Add(float64(size))
+}
+
+func (m *fstreeMetrics) AddPut(shardID, path string, size int) {
+	m.put.With(prometheus.Labels{
+		shardIDLabel: shardID,
+		pathLabel:    path,
+	}).Add(float64(size))
+}