these 3 derivations will be built:
  /nix/store/w6789rzzlsfaihxfr3fmy5q7xcbbx7hj-docker-image-sources.drv
  /nix/store/xfkdhfyqvjl7wbq9azhns1lfayc5688y-docker-image-inputs.drv
  /nix/store/7xnwf7pqnbzfkxyjlyr26qshgsrdpcwy-docker-image-inputs-hash.drv