Allow loading environment variables from files

lib/modules/rclone.nix

@@ -46,10 +46,16 @@ let
           default = { };
         };
 
+        secrets = lib.mkOption {
+          type = lib.types.attrsOf (lib.types.either lib.types.path lib.types.str);
+          description = "A set of environment variables to load from files.";
+          default = { };
+        };
+
         secretsScript = lib.mkOption {
           type = lib.types.lines;
           description = "A script for loading secrets before launching the sync.";
-          default = [];
+          default = "";
         };
 
         config = lib.mkOption {
@@ -58,6 +64,15 @@ let
           visible = false;
         };
       };
+
+      config = {
+        secretsScript = builtins.concatStringsSep
+          "\n"
+          (builtins.attrValues (
+            builtins.mapAttrs
+              (name: path: "${name}=\"$(cat ${lib.escapeShellArg path})\"")
+              config.secrets));
+      };
     });
 
   mkWebdavProvider = (
@@ -108,6 +123,10 @@ let
             (mkIfNotNull config.username { user = config.username; })
             (mkIfNotNull config.obscuredPassword { pass = config.obscuredPassword; })
           ];
+
+          secrets = lib.optionalAttrs (config.obscuredPasswordFile != null) {
+            RCLONE_WEBDAV_PASS = config.obscuredPasswordFile;
+          };
         };
       }));