@e2b/dockerfile-utils

Dockerfile parser and shell lexer ported from BuildKit and a .dockerignore matcher ported from moby/patternmatcher, with no runtime dependencies. Used by the E2B SDK to implement Template.fromDockerfile and to filter the build context.

import { parseDockerfileAst, ShellLex } from '@e2b/dockerfile-utils'

const ast = parseDockerfileAst(`
FROM node:24 AS build
ENV KEY="a  b" OTHER=c
RUN <<EOF
npm ci
npm run build
EOF
`)

for (const instruction of ast.instructions) {
  console.log(instruction.name, instruction.flags, instruction.args)
}

const lex = new ShellLex(ast.escapeToken)
lex.processWords('KEY="a  b" OTHER=c') // ['KEY=a  b', 'OTHER=c']

parseDockerfileAst handles parser directives (# escape=, # syntax=), comments (including inside line continuations), builder flags, JSON/exec forms and heredocs, and reports line numbers and warnings. ShellLex splits and unquotes words the way BuildKit does, preserving $VAR / ${VAR:-default} references for later expansion.

import { PatternMatcher } from '@e2b/dockerfile-utils'

const matcher = new PatternMatcher(['node_modules', '*.log', '!keep.log'])
matcher.matches('node_modules/pkg/index.js') // true
matcher.matches('keep.log') // false

PatternMatcher applies .dockerignore semantics to slash-separated paths relative to the context root: a pattern matching a directory excludes everything under it, and ! patterns re-include paths (the last matching pattern wins). An invalid pattern throws a plain Error.