Kubernetes Label / Annotation Value Regex for Go

What this pattern does

This page provides a well-structured, multi-part regular expression for matching kubernetes label / annotation value, ported and verified for Go. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Go project — whether you're validating in a Gin handler, a gRPC service, or a command-line tool.

Go Implementation

// Kubernetes Label / Annotation Value
// ReDoS-safe | RegexVault — Dev & Systems > Config

package validation

import "regexp"

var kubernetesLabelAnnotationValueRe = regexp.MustCompile(`^[a-zA-Z0-9](?:[a-zA-Z0-9_.\-]{0,61}[a-zA-Z0-9])?$|^$`)

func ValidateKubernetesLabelAnnotationValue(s string) bool {
    return kubernetesLabelAnnotationValueRe.MatchString(s)
}

// Example
// fmt.Println(ValidateKubernetesLabelAnnotationValue("production")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Dev & Systems > Config category and carries a ReDoS-safe certification. That matters for Go developers because Go's RE2 engine is inherently safe from catastrophic backtracking, but this pattern has been additionally verified for correctness. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Label values can be empty (for boolean-style presence checks). Must begin and end with alphanumeric if non-empty. Max 63 chars. Label keys have a separate format (optional prefix/name with different rules).