DevOps & Cloud Tools
Dockerfile Generator
Build a cache-friendly multi-stage Dockerfile for your runtime.
Dockerfile
# syntax=docker/dockerfile:1 # Generated with TLKS Dockerfile Generator. # ---- build stage ---- FROM node:22-alpine AS build WORKDIR /app # Dependency manifests first so this layer stays cached when only source changes. COPY package*.json ./ RUN npm ci COPY . . RUN npm run build # ---- runtime stage ---- FROM node:22-alpine AS runtime WORKDIR /app COPY --from=build /app/.output ./.output # Run as an unprivileged user so a container escape starts with fewer privileges. RUN addgroup --system --gid 1001 app \ && adduser --system --uid 1001 --ingroup app app \ && chown -R app:app /app USER app ENV NODE_ENV=production EXPOSE 3000 # Adjust the path to an endpoint that reports real application health. HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 \ CMD wget -qO- http://127.0.0.1:3000/healthz || exit 1 CMD ["sh", "-lc", "node .output/server/index.mjs"]
.dockerignore
# Version control and editor state .git .gitignore .github .vscode .idea # Local environment and secrets .env .env.* *.pem *.key # Dependencies and build output (rebuilt inside the image) node_modules dist build .output .nuxt __pycache__ *.pyc target vendor # Local data and logs *.log *.sqlite coverage .DS_Store
About Dockerfile Generator
A Dockerfile is short, but the ordering of its instructions determines whether your builds take ten seconds or ten minutes. Dependency installation must come before source copying so layers can be cached, and multi-stage builds keep compilers and development dependencies out of the final image.
This generator produces a Dockerfile for the runtime you select with those properties built in: cache-friendly layer ordering, a pinned base image version, a non-root runtime user, and a health check. It also emits a matching .dockerignore, which has more impact on build time than almost any other single change.
How it works
- Choose the runtime and base image version; the generator pairs compatible builder and runtime images.
- Dependency manifests are copied and installed before application source, so changes to source do not invalidate the dependency layer.
- Multi-stage mode separates the build environment from the runtime image.
- A non-root user is created and used for the process, which satisfies most container security policies.
- Optional health checks, build arguments and port exposure are added as you enable them.
- A .dockerignore file is generated alongside the Dockerfile, excluding build output, VCS metadata and local environment files.
Input and output
Accepts
Runtime, version, port, build and start commands, package manager and a few policy toggles.
Produces
A commented Dockerfile plus a matching .dockerignore.
Privacy
Templates are rendered in your browser. Your image names and paths are never transmitted.
Dockerfile Generator FAQ
Why is a multi-stage build better?
It keeps compilers, test frameworks and development dependencies out of the final image, which reduces size and attack surface. The runtime stage only contains what the process needs.
Why does my build reinstall dependencies every time?
Because the source copy happens before the install step. Copy the dependency manifest first, install, then copy the rest of the source so the cached layer stays valid.
Do I need a .dockerignore?
Yes. Without it, node_modules, .git and local environment files are sent to the daemon as build context, which slows builds and can leak secrets into image layers.
Should I use a distroless or Alpine base image?
Alpine is small but uses musl libc, which can break native modules. Distroless images remove the shell entirely, which is more secure but harder to debug. Pick deliberately per service.
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