feat(exporters/prometheus): add explicit option to set naming scheme

Author: juliusmh

exporters/prometheus/config.go

@@ -25,6 +25,7 @@ type config struct {
 	disableScopeInfo         bool
 	namespace                string
 	resourceAttributesFilter attribute.Filter
+	validationScheme         model.ValidationScheme
 }
 
 var logDeprecatedLegacyScheme = sync.OnceFunc(func() {
@@ -137,9 +138,9 @@ func WithoutScopeInfo() Option {
 // WithNamespace configures the Exporter to prefix metric with the given namespace.
 // Metadata metrics such as target_info are not prefixed since these
 // have special behavior based on their name.
-func WithNamespace(ns string) Option {
+func WithNamespace(ns string, validationScheme model.ValidationScheme) Option {
 	return optionFunc(func(cfg config) config {
-		if model.NameValidationScheme != model.UTF8Validation { // nolint:staticcheck // We need this check to keep supporting the legacy scheme.
+		if validationScheme != model.UTF8Validation { // nolint:staticcheck // We need this check to keep supporting the legacy scheme.
 			logDeprecatedLegacyScheme()
 			// Only sanitize if prometheus does not support UTF-8.
 			ns = model.EscapeName(ns, model.NameEscapingScheme)
@@ -165,3 +166,12 @@ func WithResourceAsConstantLabels(resourceFilter attribute.Filter) Option {
 		return cfg
 	})
 }
+
+// WithValidationScheme configures the Exporter to validate label and metric names
+// according to this scheme. Defaults to UTF8Validation.
+func WithValidationScheme(scheme model.ValidationScheme) Option {
+	return optionFunc(func(cfg config) config {
+		cfg.validationScheme = scheme
+		return cfg
+	})
+}

exporters/prometheus/exporter.go

@@ -93,6 +93,7 @@ type collector struct {
 	targetInfo        prometheus.Metric
 	metricFamilies    map[string]*dto.MetricFamily
 	resourceKeyVals   keyVals
+	validationScheme  model.ValidationScheme
 }
 
 // prometheus counters MUST have a _total suffix by default:
@@ -117,6 +118,7 @@ func New(opts ...Option) (*Exporter, error) {
 		metricFamilies:           make(map[string]*dto.MetricFamily),
 		namespace:                cfg.namespace,
 		resourceAttributesFilter: cfg.resourceAttributesFilter,
+		validationScheme:         cfg.validationScheme,
 	}
 
 	if err := cfg.registerer.Register(collector); err != nil {
@@ -164,7 +166,7 @@ func (c *collector) Collect(ch chan<- prometheus.Metric) {
 		defer c.mu.Unlock()
 
 		if c.targetInfo == nil && !c.disableTargetInfo {
-			targetInfo, err := createInfoMetric(targetInfoMetricName, targetInfoDescription, metrics.Resource)
+			targetInfo, err := createInfoMetric(targetInfoMetricName, targetInfoDescription, metrics.Resource, c.validationScheme)
 			if err != nil {
 				// If the target info metric is invalid, disable sending it.
 				c.disableTargetInfo = true
@@ -195,7 +197,7 @@ func (c *collector) Collect(ch chan<- prometheus.Metric) {
 			kv.keys = append(kv.keys, scopeNameLabel, scopeVersionLabel, scopeSchemaLabel)
 			kv.vals = append(kv.vals, scopeMetrics.Scope.Name, scopeMetrics.Scope.Version, scopeMetrics.Scope.SchemaURL)
 
-			attrKeys, attrVals := getAttrs(scopeMetrics.Scope.Attributes)
+			attrKeys, attrVals := getAttrs(scopeMetrics.Scope.Attributes, c.validationScheme)
 			for i := range attrKeys {
 				attrKeys[i] = scopeLabelPrefix + attrKeys[i]
 			}
@@ -224,21 +226,21 @@ func (c *collector) Collect(ch chan<- prometheus.Metric) {
 
 			switch v := m.Data.(type) {
 			case metricdata.Histogram[int64]:
-				addHistogramMetric(ch, v, m, name, kv)
+				addHistogramMetric(ch, v, m, name, kv, c.validationScheme)
 			case metricdata.Histogram[float64]:
-				addHistogramMetric(ch, v, m, name, kv)
+				addHistogramMetric(ch, v, m, name, kv, c.validationScheme)
 			case metricdata.ExponentialHistogram[int64]:
-				addExponentialHistogramMetric(ch, v, m, name, kv)
+				addExponentialHistogramMetric(ch, v, m, name, kv, c.validationScheme)
 			case metricdata.ExponentialHistogram[float64]:
-				addExponentialHistogramMetric(ch, v, m, name, kv)
+				addExponentialHistogramMetric(ch, v, m, name, kv, c.validationScheme)
 			case metricdata.Sum[int64]:
-				addSumMetric(ch, v, m, name, kv)
+				addSumMetric(ch, v, m, name, kv, c.validationScheme)
 			case metricdata.Sum[float64]:
-				addSumMetric(ch, v, m, name, kv)
+				addSumMetric(ch, v, m, name, kv, c.validationScheme)
 			case metricdata.Gauge[int64]:
-				addGaugeMetric(ch, v, m, name, kv)
+				addGaugeMetric(ch, v, m, name, kv, c.validationScheme)
 			case metricdata.Gauge[float64]:
-				addGaugeMetric(ch, v, m, name, kv)
+				addGaugeMetric(ch, v, m, name, kv, c.validationScheme)
 			}
 		}
 	}
@@ -303,9 +305,10 @@ func addExponentialHistogramMetric[N int64 | float64](
 	m metricdata.Metrics,
 	name string,
 	kv keyVals,
+	validationScheme model.ValidationScheme,
 ) {
 	for _, dp := range histogram.DataPoints {
-		keys, values := getAttrs(dp.Attributes)
+		keys, values := getAttrs(dp.Attributes, validationScheme)
 		keys = append(keys, kv.keys...)
 		values = append(values, kv.vals...)
 
@@ -377,9 +380,10 @@ func addHistogramMetric[N int64 | float64](
 	m metricdata.Metrics,
 	name string,
 	kv keyVals,
+	validationScheme model.ValidationScheme,
 ) {
 	for _, dp := range histogram.DataPoints {
-		keys, values := getAttrs(dp.Attributes)
+		keys, values := getAttrs(dp.Attributes, validationScheme)
 		keys = append(keys, kv.keys...)
 		values = append(values, kv.vals...)
 
@@ -407,14 +411,15 @@ func addSumMetric[N int64 | float64](
 	m metricdata.Metrics,
 	name string,
 	kv keyVals,
+	validationScheme model.ValidationScheme,
 ) {
 	valueType := prometheus.CounterValue
 	if !sum.IsMonotonic {
 		valueType = prometheus.GaugeValue
 	}
 
 	for _, dp := range sum.DataPoints {
-		keys, values := getAttrs(dp.Attributes)
+		keys, values := getAttrs(dp.Attributes, validationScheme)
 		keys = append(keys, kv.keys...)
 		values = append(values, kv.vals...)
 
@@ -439,9 +444,10 @@ func addGaugeMetric[N int64 | float64](
 	m metricdata.Metrics,
 	name string,
 	kv keyVals,
+	validationScheme model.ValidationScheme,
 ) {
 	for _, dp := range gauge.DataPoints {
-		keys, values := getAttrs(dp.Attributes)
+		keys, values := getAttrs(dp.Attributes, validationScheme)
 		keys = append(keys, kv.keys...)
 		values = append(values, kv.vals...)
 
@@ -457,12 +463,12 @@ func addGaugeMetric[N int64 | float64](
 
 // getAttrs converts the attribute.Set to two lists of matching Prometheus-style
 // keys and values.
-func getAttrs(attrs attribute.Set) ([]string, []string) {
+func getAttrs(attrs attribute.Set, validationScheme model.ValidationScheme) ([]string, []string) {
 	keys := make([]string, 0, attrs.Len())
 	values := make([]string, 0, attrs.Len())
 	itr := attrs.Iter()
 
-	if model.NameValidationScheme == model.UTF8Validation { // nolint:staticcheck // We need this check to keep supporting the legacy scheme.
+	if validationScheme == model.UTF8Validation { // nolint:staticcheck // We need this check to keep supporting the legacy scheme.
 		// Do not perform sanitization if prometheus supports UTF-8.
 		for itr.Next() {
 			kv := itr.Attribute()
@@ -492,8 +498,8 @@ func getAttrs(attrs attribute.Set) ([]string, []string) {
 	return keys, values
 }
 
-func createInfoMetric(name, description string, res *resource.Resource) (prometheus.Metric, error) {
-	keys, values := getAttrs(*res.Set())
+func createInfoMetric(name, description string, res *resource.Resource, validationScheme model.ValidationScheme) (prometheus.Metric, error) {
+	keys, values := getAttrs(*res.Set(), validationScheme)
 	desc := prometheus.NewDesc(name, description, keys, nil)
 	return prometheus.NewConstMetric(desc, prometheus.GaugeValue, float64(1), values...)
 }
@@ -544,7 +550,7 @@ var unitSuffixes = map[string]string{
 // getName returns the sanitized name, prefixed with the namespace and suffixed with unit.
 func (c *collector) getName(m metricdata.Metrics, typ *dto.MetricType) string {
 	name := m.Name
-	if model.NameValidationScheme != model.UTF8Validation { // nolint:staticcheck // We need this check to keep supporting the legacy scheme.
+	if c.validationScheme != model.UTF8Validation { // nolint:staticcheck // We need this check to keep supporting the legacy scheme.
 		// Only sanitize if prometheus does not support UTF-8.
 		logDeprecatedLegacyScheme()
 		name = model.EscapeName(name, model.NameEscapingScheme)
@@ -606,7 +612,7 @@ func (c *collector) createResourceAttributes(res *resource.Resource) {
 	defer c.mu.Unlock()
 
 	resourceAttrs, _ := res.Set().Filter(c.resourceAttributesFilter)
-	resourceKeys, resourceValues := getAttrs(resourceAttrs)
+	resourceKeys, resourceValues := getAttrs(resourceAttrs, c.validationScheme)
 	c.resourceKeyVals = keyVals{keys: resourceKeys, vals: resourceValues}
 }