Python (re)

Docker Image Tag in PY

Match Docker image references with an explicit tag — e.g. nginx:1.21, mycorp/service:v2.3.1.

Try it in the PY tester →

Pattern

regexPY
\b[a-z0-9]+(?:[._\-\/][a-z0-9]+)*:[\w.\-]+\b   (flags: g)

Python (re) code

pyPython
import re

pattern = re.compile(r"\b[a-z0-9]+(?:[._\-\/][a-z0-9]+)*:[\w.\-]+\b")
input_text = "FROM nginx:1.21"
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

Image name is lowercase alphanumerics with optional . _ - / separators for registry paths. Tag follows the colon and can include letters, digits, dots, hyphens, and underscores.

Examples

Input

FROM nginx:1.21

Matches

  • nginx:1.21

Input

image: mycorp/service:v2.3.1

Matches

  • mycorp/service:v2.3.1

Input

ubuntu:latest

Matches

  • ubuntu:latest

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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