fixup invalid metric names

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

prometheus.go

@@ -5,6 +5,7 @@ import (
 	"hash/fnv"
 	"io"
 	"regexp"
+	"strings"
 	"sync"
 	"time"
 
@@ -60,6 +61,15 @@ func newString(v string) *string {
 	return &nv
 }
 
+func newName(name string) *string {
+	idx := strings.Index(name, "{")
+	if idx <= 0 {
+		return newString(name)
+	}
+
+	return newString(name[:idx])
+}
+
 func NewMeter(opts ...meter.Option) *prometheusMeter {
 	return &prometheusMeter{
 		set:          prometheus.NewRegistry(), // prometheus.DefaultRegisterer,
@@ -269,7 +279,7 @@ func (m *prometheusMeter) Write(w io.Writer, opts ...meter.Option) error {
 
 	for name, metrics := range m.counter {
 		mf := &dto.MetricFamily{
-			Name:   newString(name),
+			Name:   newName(name),
 			Type:   dto.MetricType_GAUGE.Enum(),
 			Metric: make([]*dto.Metric, 0, len(metrics.cs)),
 		}
@@ -284,7 +294,7 @@ func (m *prometheusMeter) Write(w io.Writer, opts ...meter.Option) error {
 
 	for name, metrics := range m.gauge {
 		mf := &dto.MetricFamily{
-			Name:   newString(name),
+			Name:   newName(name),
 			Type:   dto.MetricType_GAUGE.Enum(),
 			Metric: make([]*dto.Metric, 0, len(metrics.cs)),
 		}
@@ -299,7 +309,7 @@ func (m *prometheusMeter) Write(w io.Writer, opts ...meter.Option) error {
 
 	for name, metrics := range m.floatCounter {
 		mf := &dto.MetricFamily{
-			Name:   newString(name),
+			Name:   newName(name),
 			Type:   dto.MetricType_GAUGE.Enum(),
 			Metric: make([]*dto.Metric, 0, len(metrics.cs)),
 		}
@@ -314,7 +324,7 @@ func (m *prometheusMeter) Write(w io.Writer, opts ...meter.Option) error {
 
 	for name, metrics := range m.histogram {
 		mf := &dto.MetricFamily{
-			Name:   newString(name),
+			Name:   newName(name),
 			Type:   dto.MetricType_HISTOGRAM.Enum(),
 			Metric: make([]*dto.Metric, 0, len(metrics.cs)),
 		}
@@ -329,7 +339,7 @@ func (m *prometheusMeter) Write(w io.Writer, opts ...meter.Option) error {
 
 	for name, metrics := range m.summary {
 		mf := &dto.MetricFamily{
-			Name:   newString(name),
+			Name:   newName(name),
 			Type:   dto.MetricType_SUMMARY.Enum(),
 			Metric: make([]*dto.Metric, 0, len(metrics.cs)),
 		}