packages/build-support/hydrate-asset-directory: init

packages/build-support/default.nix

@@ -5,7 +5,11 @@
     ./options.nix
   ];
 
-  builders = {
+  builders = rec {
     fetchAsset = pkgs.callPackage ./fetch-asset { };
+
+    hydrateAssetDirectory = pkgs.callPackage ./hydrate-asset-directory {
+      inherit fetchAsset;
+    };
   };
 }

packages/build-support/hydrate-asset-directory/default.nix

@@ -0,0 +1,33 @@
+{ lib, fetchAsset, runCommandNoCC }:
+
+rootDir: let
+
+  prefix = ((toString rootDir) + "/");
+
+  files = lib.filesystem.listFilesRecursive rootDir;
+
+  hydrate = index: fetchAsset { inherit index; };
+
+  isDvc = lib.strings.hasSuffix ".dvc";
+
+  relative = file: lib.strings.removePrefix prefix (toString file);
+
+  files' = builtins.partition isDvc files;
+
+  filesRaw = map relative files'.wrong;
+
+  filesDvc = map (file: rec {
+    dvc = hydrate file;
+    installPath = (builtins.dirOf (relative file)) + "/${dvc.name}";
+  }) files'.right;
+
+  installFile = file: "install -Dm644 ${file} $out/${file}";
+
+  installDvc = dvc: "install -Dm644 ${dvc.dvc} $out/${dvc.installPath}";
+
+in runCommandNoCC (builtins.baseNameOf rootDir) {} ''
+  cd ${rootDir}
+  mkdir $out
+  ${lib.concatStringsSep "\n" (map installFile filesRaw)}
+  ${lib.concatStringsSep "\n" (map installDvc filesDvc)}
+''