Docker Port Mapping Regex for Python

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching docker port mapping, 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

# Docker Port Mapping
# ReDoS-safe | RegexVault — Dev & Systems > Docker

import re

docker_port_mapping_pattern = re.compile(r'^(?:(?:(?:(?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])\.){3}(?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9]):)?(?:6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3}):)?(?:6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3})(?:/(tcp|udp|sctp))?$')

def validate_docker_port_mapping(value: str) -> bool:
    return bool(docker_port_mapping_pattern.fullmatch(value))

# Example
print(validate_docker_port_mapping("8080:80"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Dev & Systems > Docker 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

Protocol defaults to tcp. Exposing on 0.0.0.0 (all interfaces) is the default. Use 127.0.0.1 to restrict to localhost for development services.