Kubernetes Label / Annotation Value Regex for Python

What this pattern does

This page provides a well-structured, multi-part regular expression for matching kubernetes label / annotation value, ported and verified for Python. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

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

import re

kubernetes_label_annotation_value_pattern = re.compile(r'^[a-zA-Z0-9](?:[a-zA-Z0-9_.\-]{0,61}[a-zA-Z0-9])?$|^$')

def validate_kubernetes_label_annotation_value(value: str) -> bool:
    return bool(kubernetes_label_annotation_value_pattern.fullmatch(value))

# Example
print(validate_kubernetes_label_annotation_value("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 Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. 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).