JavaScript / ECMAScript

Docker Image Tag in JS

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

Try it in the JS tester →

Pattern

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

JavaScript / ECMAScript code

jsJavaScript
const re = new RegExp("\\b[a-z0-9]+(?:[._\\-\\/][a-z0-9]+)*:[\\w.\\-]+\\b", "g");
const input = "FROM nginx:1.21";
const matches = [...input.matchAll(re)];
console.log(matches.map(m => m[0]));

Uses `String.prototype.matchAll` for global iteration (Node 12+ / all modern browsers).

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

Python (re)

Supported

See how this pattern looks (and behaves) in Python's stdlib `re` module.

Go (RE2)

Supported

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

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