wip: templates

further increases parity with
https://git.clan.lol/clan/clan-core/src/branch/main/nixosModules/clanCore/vars/interface.nix,
particularly:
-
f540ab91a1 (diff-7b681998bb14b48b80f83251424be17c6e3ce3bf)
-
19a251d6fc (diff-7b681998bb14b48b80f83251424be17c6e3ce3bf)
-
222915a9ed (diff-7b681998bb14b48b80f83251424be17c6e3ce3bf)

backends/on-machine.nix

@@ -46,6 +46,12 @@ let
           fi
         '') (lib.attrValues gen.files)}
 
+        # outputs
+        out=$(mktemp -d)
+        trap 'rm -rf $out' EXIT
+        export out
+        mkdir -p "$out"
+
         if [ $all_files_missing = false ] && [ $all_files_present = false ] ; then
           echo "Inconsistent state for generator: ${gen.name}"
           exit 1
@@ -54,6 +60,15 @@ let
           echo "All secrets for ${gen.name} are present"
         elif [ $all_files_missing = true ] ; then
 
+          # templates
+          templates=$(mktemp -d)
+          trap 'rm -rf $templates' EXIT
+          export templates
+          mkdir -p "$templates"
+          ${lib.concatMapStringsSep "\n" (file: ''
+            cp "${file.template}" "$templates/${file.name}"
+          '') (lib.filter (file: file.template != null) (lib.attrValues gen.files))}
+
           # prompts
           prompts=$(mktemp -d)
           trap 'rm -rf $prompts' EXIT
@@ -80,12 +95,6 @@ let
             '') (lib.attrValues config.vars.generators.${input}.files)}
           '') gen.dependencies}
 
-          # outputs
-          out=$(mktemp -d)
-          trap 'rm -rf $out' EXIT
-          export out
-          mkdir -p "$out"
-
           (
             # prepare PATH
             unset PATH
@@ -112,8 +121,15 @@ let
             mkdir -p "$(dirname "$OUT_FILE")"
             mv "$out"/${file.name} "$OUT_FILE"
           '') (lib.attrValues gen.files)}
-          rm -rf "$out"
         fi
+
+        # move the files to the correct location
+        ${lib.concatMapStringsSep "\n" (file: ''
+          OUT_FILE="$OUT_DIR"/${if file.secret then "secret" else "public"}/${file.generator}/${file.name}
+          chown ${file.owner}:${file.group} "''${OUT_FILE}"
+          chmod ${file.mode} "''${OUT_FILE}"
+        '') (lib.attrValues gen.files)}
+        rm -rf "$out"
       '') sortedGenerators}
     '';
   };

options.nix

@@ -82,6 +82,19 @@
                       default = generator.config.name;
                       defaultText = "Name of the generator";
                     };
+                    owner = lib.mkOption {
+                      description = "The user name or id that will own the file.";
+                      default = "root";
+                    };
+                    group = lib.mkOption {
+                      description = "The group name or id that will own the file.";
+                      default = "root";
+                    };
+                    mode = lib.mkOption {
+                      type = lib.types.strMatching "^[0-7]{4}$";
+                      description = "The unix file mode of the file. Must be a 4-digit octal number.";
+                      default = "0400";
+                    };
                     deploy = lib.mkOption {
                       description = ''
                         Whether the file should be deployed to the target machine.
@@ -106,6 +119,21 @@
                       type = lib.types.nullOr lib.types.str;
                       default = null;
                     };
+                    placeholder = lib.mkOption {
+                      description = ''
+                        A placeholder that may be used to safely reference the variable in a template.
+                      '';
+                      readOnly = true;
+                      default = "<VARS:${builtins.hashString "sha256" "${generator.config.name}:${file.config.name}"}:PLACEHOLDER>";
+                    };
+                    template = lib.mkOption {
+                      description = ''
+                        A template file with placeholders from the generator's dependencies.
+                        These will be substituted.
+                      '';
+                      type = lib.types.nullOr lib.types.path;
+                      default = null;
+                    };
                   };
                 })
               );
@@ -172,6 +200,8 @@
                   - $in: The directory containing the output values of all declared dependencies
                   - $out: The output directory to put the generated files
                   - $prompts: The directory containing the prompted values as files
+                  - $templates: The template files, with placeholders - to be replaced in the script like
+                      cat $templates/foo | sed "s/''${config.vars.generators.bar.files.baz.placeholder}/$(cat "$in/bar/baz")/g" > "$out/foo"
                 The script should produce the files specified in the 'files' attribute under $out.
               '';
               type = lib.types.either lib.types.str lib.types.path;