1 files changed, 57 insertions, 0 deletions
diff --git a/vendor/github.com/prometheus/otlptranslator/normalize_label.go b/vendor/github.com/prometheus/otlptranslator/normalize_label.go
new file mode 100644
index 000000000..aa771f784
--- /dev/null
+++ b/vendor/github.com/prometheus/otlptranslator/normalize_label.go
@@ -0,0 +1,57 @@
+// Copyright 2025 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// Provenance-includes-location: https://github.com/prometheus/prometheus/blob/93e991ef7ed19cc997a9360c8016cac3767b8057/storage/remote/otlptranslator/prometheus/normalize_label.go
+// Provenance-includes-license: Apache-2.0
+// Provenance-includes-copyright: Copyright The Prometheus Authors
+// Provenance-includes-location: https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/95e8f8fdc2a9dc87230406c9a3cf02be4fd68bea/pkg/translator/prometheus/normalize_label.go
+// Provenance-includes-license: Apache-2.0
+// Provenance-includes-copyright: Copyright The OpenTelemetry Authors.
+
+package otlptranslator
+
+import (
+	"strings"
+	"unicode"
+)
+
+// LabelNamer is a helper struct to build label names.
+type LabelNamer struct {
+	UTF8Allowed bool
+}
+
+// Build normalizes the specified label to follow Prometheus label names standard.
+//
+// See rules at https://prometheus.io/docs/concepts/data_model/#metric-names-and-labels.
+//
+// Labels that start with non-letter rune will be prefixed with "key_".
+// An exception is made for double-underscores which are allowed.
+//
+// If UTF8Allowed is true, the label is returned as is. This option is provided just to
+// keep a consistent interface with the MetricNamer.
+func (ln *LabelNamer) Build(label string) string {
+	// Trivial case.
+	if len(label) == 0 || ln.UTF8Allowed {
+		return label
+	}
+
+	label = sanitizeLabelName(label)
+
+	// If label starts with a number, prepend with "key_".
+	if unicode.IsDigit(rune(label[0])) {
+		label = "key_" + label
+	} else if strings.HasPrefix(label, "_") && !strings.HasPrefix(label, "__") {
+		label = "key" + label
+	}
+
+	return label
+}