Add internal ID to metric

metrics/metric.go

@@ -43,6 +43,10 @@ type Options struct {
 	// Name defines an optional human readable name for the metric.
 	Name string
 
+	// InternalID specifies an alternative internal ID that will be used when
+	// exposing the metric via the API in a structured format.
+	InternalID string
+
 	// AlertLimit defines an upper limit that triggers an alert.
 	AlertLimit float64
 

metrics/module.go

@@ -92,6 +92,10 @@ func register(m Metric) error {
 		if m.LabeledID() == registeredMetric.LabeledID() {
 			return ErrAlreadyRegistered
 		}
+		if m.Opts().InternalID != "" &&
+			m.Opts().InternalID == registeredMetric.Opts().InternalID {
+			return fmt.Errorf("%w with this internal ID", ErrAlreadyRegistered)
+		}
 	}
 
 	// Add new metric to registry and sort it.