nixdock.sh

#!/usr/bin/env bash
# Generate a Docker image from a Nix store path.
set -e

USAGE='USAGE: ./nixdock <storepath> [<entrypoint>] [<dockertag>]'

if [[ $# -lt 1 || $# -gt 3 ]]; then
  echo "$USAGE" >&2; exit 1
elif [[ "$1" == "--help" ]]; then
  echo "$USAGE"; exit 0
fi

drv=$1
entrypoint=${2:+ENTRYPOINT [\"$2\"]}
tag=${3:-}

path=$(nix-store --realize "$drv")
img=$(tar -cP -C "$path" \
          ./ $(nix-store --query --requisites "$path") \
          | docker import ${entrypoint:+-c "$entrypoint"} - "$tag")

echo "Store path: ${path}" >&2
[[ -n "$tag" ]] && echo "Docker tag: ${tag}" >&2
if [[ -n "$entrypoint" ]]; then
  echo -n "Entrypoint: " >&2
  docker inspect "$img" | jq -c .[].Config.Entrypoint >&2
fi

echo "$img"