docker

Dockerfile authoring rules distilled from Docker's official best practices.

npx rulepack add docker

What it covers

Multi-stage builds — separate build env from a lean runtime image
Minimal, pinned (version + digest) official base images
Cache-friendly instruction ordering (least → most frequently changing)
Layer hygiene: combine RUN commands, clean up in the same layer, sort args
apt-get done right (update + install in one RUN, prune lists)
COPY over ADD; exec-form CMD/ENTRYPOINT; absolute WORKDIR
Security: run as non-root USER, never bake secrets (RUN --mount=type=secret)
.dockerignore, one concern per container, ephemeral/stateless design

MIT