nixos/services.ddclient: add secretsFile option

nixos/modules/services/networking/ddclient.nix

@@ -19,11 +19,15 @@ let
     ${lib.optionalString (cfg.use == "" && cfg.usev4 != "") "usev4=${cfg.usev4}"}
     ${lib.optionalString (cfg.use == "" && cfg.usev6 != "") "usev6=${cfg.usev6}"}
     login=${cfg.username}
-    password=${
+    ${
       if cfg.protocol == "nsupdate" then
         "/run/${RuntimeDirectory}/ddclient.key"
+      else if (cfg.passwordFile != null) then
+        "password=@password_placeholder@"
+      else if (cfg.secretsFile != null) then
+        "@secrets_placeholder@"
       else
-        "@password_placeholder@"
+        ""
     }
     protocol=${cfg.protocol}
     ${lib.optionalString (cfg.script != "") "script=${cfg.script}"}
@@ -49,6 +53,10 @@ let
         ''
           "${pkgs.replace-secret}/bin/replace-secret" "@password_placeholder@" "${cfg.passwordFile}" "/run/${RuntimeDirectory}/ddclient.conf"
         ''
+      else if (cfg.secretsFile != null) then
+        ''
+          "${pkgs.replace-secret}/bin/replace-secret" "@secrets_placeholder@" "${cfg.secretsFile}" "/run/${RuntimeDirectory}/ddclient.conf"
+        ''
       else
         ''
           sed -i '/^password=@password_placeholder@$/d' /run/${RuntimeDirectory}/ddclient.conf
@@ -126,6 +134,16 @@ in
         '';
       };
 
+      secretsFile = lib.mkOption {
+        default = null;
+        type = nullOr str;
+        description = ''
+          A file containing the secrets for the dynamic DNS provider.
+          This file should contain lines of valid secrets in the format specified by the ddclient documentation.
+          If this option is set, it overrides the `passwordFile` option.
+        '';
+      };
+
       interval = lib.mkOption {
         default = "10min";
         type = str;