nix-docker

Dockerfile

FROM nixos/nix AS build

RUN nix-channel --update

# Build a profile and package store in the /scratch directory.  Only the files we install
# during this docker build will end up in this profile.
RUN mkdir -p /scratch/store

# Install all desired packages into the scratch profile. It's important to know that the
# packages themselve are installed in /nix/store during this step and the /scratch/profile
# simply symlinks to them.
RUN nix-env --profile /scratch/profile -i cowsay

# Now copy all the files associated with /scratch/profile into /scratch/store.
RUN cp -va $(nix-store -qR scratch/profile) /scratch/store

FROM scratch

# Copy the /scratch directory created above to /nix, fixing the symlinks.
COPY --from=build /scratch/profile /nix/profile
COPY --from=build /scratch/store /nix/store

ENV PATH=/nix/profile/bin:$PATH

CMD ["cowsay", "moooooo!!!"]