pkgs.dockerTools.buildNixShellImage

The following is the current implementation of this function.

buildNixShellImage =
    {
      drv,
      compressor ? "gz",
      ...
    }@args:
    let
      stream = streamNixShellImage (builtins.removeAttrs args [ "compressor" ]);
      compress = compressorForImage compressor drv.name;
    in
    runCommand "${drv.name}-env.tar${compress.ext}" {
      inherit (stream) imageName;
      passthru = { inherit (stream) imageTag; };
      nativeBuildInputs = compress.nativeInputs;
    } "${stream} | ${compress.compress} > $out";