these 3 derivations will be built:
  /nix/store/jgq5yh3lcswffqmgw9hfvq0b81cjjsxc-docker-image-sources.drv
  /nix/store/qhci495x4j0xd2mk9kjk0l2issmjcx3x-docker-image-inputs.drv
  /nix/store/8xap8cxkf1b7nk3frwjsm26pa3r98735-docker-image-inputs-hash.drv