prometheusexporter: Expose new otlptranslator options

.chloggen/owilliams_newconfig.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: prometheusexporter, prometheusremotewriteexporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Added new configurations options to restore old name translation behavior for those users whose names are broken by the new default behavior.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [43077]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

exporter/prometheusexporter/collector.go

@@ -92,7 +92,9 @@ func configureMetricNamer(config *Config) otlptranslator.MetricNamer {
 func configureLabelNamer(config *Config) otlptranslator.LabelNamer {
 	_, utf8Allowed := getTranslationConfiguration(config)
 	return otlptranslator.LabelNamer{
-		UTF8Allowed: utf8Allowed,
+		UTF8Allowed:                 utf8Allowed,
+		UnderscoreLabelSanitization: config.UnderscoreLabelSanitization,
+		PreserveMultipleUnderscores: config.PreserveMultipleUnderscores,
 	}
 }
 

exporter/prometheusexporter/config.go

@@ -44,6 +44,20 @@ type Config struct {
 	// TranslationStrategy controls how OTLP metric and attribute names are translated into Prometheus metric and label names.
 	// When set, this takes precedence over AddMetricSuffixes.
 	TranslationStrategy translationStrategy `mapstructure:"translation_strategy"`
+
+	// UnderscoreLabelSanitization, if true, enables prepending 'key' to labels
+	// starting with '_'. Reserved labels starting with `__` are not modified.
+	// Included for compatibility with default previous behavior.
+	//
+	// Deprecated: This will be removed in a future version.
+	UnderscoreLabelSanitization bool `mapstructure:"underscore_label_sanitization"`
+
+	// PreserveMultipleUnderscores enables preserving of multiple
+	// consecutive underscores in label names when UTF8Allowed is false.
+	// This option is discouraged as it violates the OpenTelemetry to Prometheus
+	// specification https://github.com/open-telemetry/opentelemetry-specification/blob/v1.38.0/specification/compatibility/prometheus_and_openmetrics.md#otlp-metric-points-to-prometheus),
+	// but may be needed for compatibility with legacy systems that rely on the old behavior.
+	PreserveMultipleUnderscores bool `mapstructure:"preserve_multiple_underscores"`
 }
 
 var _ component.Config = (*Config)(nil)

exporter/prometheusremotewriteexporter/config.go

@@ -60,6 +60,20 @@ type Config struct {
 
 	// RemoteWriteProtoMsg controls whether prometheus remote write v1 or v2 is sent.
 	RemoteWriteProtoMsg config.RemoteWriteProtoMsg `mapstructure:"protobuf_message,omitempty"`
+
+	// UnderscoreLabelSanitization, if true, enables prepending 'key' to labels
+	// starting with '_'. Reserved labels starting with `__` are not modified.
+	// Included for compatibility with default previous behavior.
+	//
+	// Deprecated: This will be removed in a future version.
+	UnderscoreLabelSanitization bool `mapstructure:"underscore_label_sanitization"`
+
+	// PreserveMultipleUnderscores enables preserving of multiple
+	// consecutive underscores in label names when UTF8Allowed is false.
+	// This option is discouraged as it violates the OpenTelemetry to Prometheus
+	// specification https://github.com/open-telemetry/opentelemetry-specification/blob/v1.38.0/specification/compatibility/prometheus_and_openmetrics.md#otlp-metric-points-to-prometheus),
+	// but may be needed for compatibility with legacy systems that rely on the old behavior.
+	PreserveMultipleUnderscores bool `mapstructure:"preserve_multiple_underscores"`
 }
 
 type TargetInfo struct {

exporter/prometheusremotewriteexporter/exporter.go

@@ -305,7 +305,10 @@ func (prwe *prwExporter) PushMetrics(ctx context.Context, md pmetric.Metrics) er
 }
 
 func validateAndSanitizeExternalLabels(cfg *Config) (map[string]string, error) {
-	namer := otlptranslator.LabelNamer{}
+	namer := otlptranslator.LabelNamer{
+		UnderscoreLabelSanitization: cfg.UnderscoreLabelSanitization,
+		PreserveMultipleUnderscores: cfg.PreserveMultipleUnderscores,
+	}
 	sanitizedLabels := make(map[string]string)
 	for key, value := range cfg.ExternalLabels {
 		if key == "" || value == "" {

pkg/translator/prometheusremotewrite/helper.go

@@ -529,7 +529,7 @@ func addResourceTargetInfo(resource pcommon.Resource, settings Settings, timesta
 		name = settings.Namespace + "_" + name
 	}
 
-	labels, err := createAttributes(resource, attributes, settings.ExternalLabels, identifyingAttrs, false, otlptranslator.LabelNamer{}, model.MetricNameLabel, name)
+	labels, err := createAttributes(resource, attributes, settings.ExternalLabels, identifyingAttrs, false, otlptranslator.LabelNamer{UnderscoreLabelSanitization: settings.UnderscoreLabelSanitization, PreserveMultipleUnderscores: settings.PreserveMultipleUnderscores}, model.MetricNameLabel, name)
 	if err != nil {
 		return err
 	}

pkg/translator/prometheusremotewrite/helper_test.go

@@ -244,13 +244,15 @@ func Test_timeSeriesSignature(t *testing.T) {
 // collision happens. It does not check whether labels are not sorted
 func Test_createLabelSet(t *testing.T) {
 	tests := []struct {
-		name           string
-		resource       pcommon.Resource
-		orig           pcommon.Map
-		externalLabels map[string]string
-		extras         []string
-		want           []prompb.Label
-		expectErr      bool
+		name                        string
+		resource                    pcommon.Resource
+		orig                        pcommon.Map
+		externalLabels              map[string]string
+		extras                      []string
+		want                        []prompb.Label
+		expectErr                   bool
+		underscoreLabelSanitization bool
+		preserveMultipleUnderscores bool
 	}{
 		{
 			name:           "labels_clean",
@@ -302,6 +304,32 @@ func Test_createLabelSet(t *testing.T) {
 			extras:         []string{label31 + dirty1, value31, label32, value32},
 			want:           getPromLabels(label11+"_", value11, "_"+label12, value12, label31+"_", value31, label32, value32),
 		},
+		{
+			name:                        "labels_dirty_with_sanitization",
+			resource:                    pcommon.NewResource(),
+			orig:                        lbs1Dirty,
+			externalLabels:              map[string]string{},
+			extras:                      []string{label31 + dirty1, value31, label32, value32},
+			want:                        getPromLabels(label11+"_", value11, "key_"+label12, value12, label31+"_", value31, label32, value32),
+			underscoreLabelSanitization: true,
+		},
+		{
+			name:           "labels_dont_preserve_underscores",
+			resource:       pcommon.NewResource(),
+			orig:           lbs1,
+			externalLabels: map[string]string{},
+			extras:         []string{label61, value61},
+			want:           getPromLabels(label11, value11, label12, value12, "test_label61", value61),
+		},
+		{
+			name:                        "labels_preserve_underscores",
+			resource:                    pcommon.NewResource(),
+			orig:                        lbs1,
+			externalLabels:              map[string]string{},
+			extras:                      []string{label61, value61},
+			want:                        getPromLabels(label11, value11, label12, value12, "test____label61", value61),
+			preserveMultipleUnderscores: true,
+		},
 		{
 			name:           "no_original_case",
 			resource:       pcommon.NewResource(),
@@ -367,11 +395,23 @@ func Test_createLabelSet(t *testing.T) {
 			extras:         []string{label31, value31, label32, value32},
 			want:           getPromLabels(label11, value11, label12, value12, label51, value51, label41, value41, label31, value31, label32, value32),
 		},
+		{
+			name:                        "sanitize_labels_starts_with_underscore_with_sanitization",
+			resource:                    pcommon.NewResource(),
+			orig:                        lbs3,
+			externalLabels:              exlbs1,
+			extras:                      []string{label31, value31, label32, value32},
+			want:                        getPromLabels(label11, value11, label12, value12, "key"+label51, value51, label41, value41, label31, value31, label32, value32),
+			underscoreLabelSanitization: true,
+		},
 	}
-	// run tests
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			got, err := createAttributes(tt.resource, tt.orig, tt.externalLabels, nil, true, otlptranslator.LabelNamer{}, tt.extras...)
+			labelNamer := otlptranslator.LabelNamer{
+				UnderscoreLabelSanitization: tt.underscoreLabelSanitization,
+				PreserveMultipleUnderscores: tt.preserveMultipleUnderscores,
+			}
+			got, err := createAttributes(tt.resource, tt.orig, tt.externalLabels, nil, true, labelNamer, tt.extras...)
 			if tt.expectErr {
 				require.Error(t, err)
 				return

pkg/translator/prometheusremotewrite/metrics_to_prw.go

@@ -18,11 +18,13 @@ import (
 )
 
 type Settings struct {
-	Namespace         string
-	ExternalLabels    map[string]string
-	DisableTargetInfo bool
-	AddMetricSuffixes bool
-	SendMetadata      bool
+	Namespace                   string
+	ExternalLabels              map[string]string
+	DisableTargetInfo           bool
+	AddMetricSuffixes           bool
+	SendMetadata                bool
+	UnderscoreLabelSanitization bool
+	PreserveMultipleUnderscores bool
 }
 
 // FromMetrics converts pmetric.Metrics to Prometheus remote write format.
@@ -53,7 +55,7 @@ func newPrometheusConverter(settings Settings) *prometheusConverter {
 		unique:      map[uint64]*prompb.TimeSeries{},
 		conflicts:   map[uint64][]*prompb.TimeSeries{},
 		metricNamer: otlptranslator.MetricNamer{WithMetricSuffixes: settings.AddMetricSuffixes, Namespace: settings.Namespace},
-		labelNamer:  otlptranslator.LabelNamer{},
+		labelNamer:  otlptranslator.LabelNamer{UnderscoreLabelSanitization: settings.UnderscoreLabelSanitization, PreserveMultipleUnderscores: settings.PreserveMultipleUnderscores},
 		unitNamer:   otlptranslator.UnitNamer{},
 	}
 }

pkg/translator/prometheusremotewrite/metrics_to_prw_v2.go

@@ -57,7 +57,7 @@ func newPrometheusConverterV2(settings Settings) *prometheusConverterV2 {
 		conflicts:   map[uint64][]*writev2.TimeSeries{},
 		symbolTable: writev2.NewSymbolTable(),
 		metricNamer: otlptranslator.MetricNamer{WithMetricSuffixes: settings.AddMetricSuffixes, Namespace: settings.Namespace},
-		labelNamer:  otlptranslator.LabelNamer{},
+		labelNamer:  otlptranslator.LabelNamer{UnderscoreLabelSanitization: settings.UnderscoreLabelSanitization, PreserveMultipleUnderscores: settings.PreserveMultipleUnderscores},
 		unitNamer:   otlptranslator.UnitNamer{},
 	}
 }

pkg/translator/prometheusremotewrite/testutils_test.go

@@ -39,6 +39,8 @@ var (
 	value41            = "test_value41"
 	label51            = "_test_label51"
 	value51            = "test_value51"
+	label61            = "test#$%^label61"
+	value61            = "test_value61"
 	dirty1             = "%"
 	dirty2             = "?"
 	traceIDValue1      = "4303853f086f4f8c86cf198b6551df84"