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.from_dockerfile and to filter the build context.

from e2b_dockerfile_utils import ShellLex, parse_dockerfile_ast

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

for instruction in ast.instructions:
    print(instruction.name, instruction.flags, instruction.args)

lex = ShellLex(ast.escape_token)
lex.process_words('KEY="a  b" OTHER=c')  # ['KEY=a  b', 'OTHER=c']

parse_dockerfile_ast 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.

from e2b_dockerfile_utils import PatternMatcher

matcher = 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 raises a plain ValueError.