[#451] metrics: Move to internal

`metrics` don't look like something others want to import.

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

internal/metrics/mode.go

@@ -0,0 +1,89 @@
+package metrics
+
+import (
+	"git.frostfs.info/TrueCloudLab/frostfs-observability/metrics"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+type shardIDModeValue struct {
+	modeValue *prometheus.GaugeVec
+}
+
+func newShardIDMode(subsystem, name, help string) *shardIDModeValue {
+	return &shardIDModeValue{
+		modeValue: metrics.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: namespace,
+				Subsystem: subsystem,
+				Name:      name,
+				Help:      help,
+			}, []string{shardIDLabel, modeLabel}),
+	}
+}
+
+func (m *shardIDModeValue) SetMode(shardID, mode string) {
+	m.modeValue.DeletePartialMatch(prometheus.Labels{
+		shardIDLabel: shardID,
+	})
+
+	m.modeValue.With(prometheus.Labels{
+		shardIDLabel: shardID,
+		modeLabel:    mode,
+	}).Set(1)
+}
+
+func (m *shardIDModeValue) Delete(shardID string) {
+	m.modeValue.DeletePartialMatch(prometheus.Labels{
+		shardIDLabel: shardID,
+	})
+}
+
+type shardIDPathModeValue struct {
+	modeValue *prometheus.GaugeVec
+}
+
+func newShardIDPathMode(subsystem, name, help string) *shardIDPathModeValue {
+	return &shardIDPathModeValue{
+		modeValue: metrics.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Namespace: namespace,
+				Subsystem: subsystem,
+				Name:      name,
+				Help:      help,
+			}, []string{shardIDLabel, pathLabel, modeLabel}),
+	}
+}
+
+func (m *shardIDPathModeValue) SetMode(shardID, path, mode string) {
+	m.modeValue.DeletePartialMatch(prometheus.Labels{
+		shardIDLabel: shardID,
+		pathLabel:    path,
+	})
+
+	m.modeValue.With(prometheus.Labels{
+		shardIDLabel: shardID,
+		pathLabel:    path,
+		modeLabel:    mode,
+	}).Set(1)
+}
+
+func (m *shardIDPathModeValue) Delete(shardID, path string) {
+	m.modeValue.DeletePartialMatch(prometheus.Labels{
+		shardIDLabel: shardID,
+		pathLabel:    path,
+	})
+}
+
+func (m *shardIDPathModeValue) DeleteByShardID(shardID string) {
+	m.modeValue.DeletePartialMatch(prometheus.Labels{
+		shardIDLabel: shardID,
+	})
+}
+
+func modeFromBool(readOnly bool) string {
+	modeValue := readWriteMode
+	if readOnly {
+		modeValue = readOnlyMode
+	}
+	return modeValue
+}