these 3 derivations will be built:
  /nix/store/myk0953cyscgmw92vbnqbg06h0nd4wkd-docker-image-sources.drv
  /nix/store/6w6xza5kdnafrlb4qkip78h0w3bapzsw-docker-image-inputs.drv
  /nix/store/81a9pv4dnpalcr18d0qyplkinbq979zc-docker-image-inputs-hash.drv