Python (re)

Kubernetes Label (key=value) in PY

Validate Kubernetes label `key=value` pairs per the K8s naming spec.

Try it in the PY tester →

Pattern

regexPY
^([a-zA-Z0-9](?:[\w.\-]{0,61}[a-zA-Z0-9])?)=([a-zA-Z0-9](?:[\w.\-]{0,61}[a-zA-Z0-9])?)?$

Python (re) code

pyPython
import re

pattern = re.compile(r"^([a-zA-Z0-9](?:[\w.\-]{0,61}[a-zA-Z0-9])?)=([a-zA-Z0-9](?:[\w.\-]{0,61}[a-zA-Z0-9])?)?$")
input_text = "app=myapp"
for m in pattern.finditer(input_text):
    print(m.group(0))

Stdlib `re` module — no third-party dependency. Works on Python 3.6+.

How the pattern works

Both key and value follow the same rule: 1–63 chars, must start AND end with alphanumeric, can contain underscores/dots/hyphens in the middle. The value group is optional (empty values are allowed). Anchored with ^ and $ for strict full-string matching.

Examples

Input

app=myapp

Matches

  • app=myapp

Input

version=v1.2.3

Matches

  • version=v1.2.3

Input

-bad=value

No match

—

Same pattern, other engines

JavaScript / ECMAScript

Supported

See how this pattern looks (and behaves) in JavaScript's built-in RegExp.

Go (RE2)

Supported

See how this pattern looks (and behaves) in Go's `regexp` package (RE2 engine).

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