Nix: tweak retention options and defaults

modules/nixos/default.nix

@@ -16,7 +16,7 @@
     ];
 
     # Install the nos helper script
-    nixos-operations-script.enable = true;
+    nix.nixos-operations-script.enable = true;
   };
 
   programs = {

modules/nixos/services/autoupgrade/default.nix

@@ -59,7 +59,7 @@ in
     ];
 
     # Deploy update script
-    ${namespace}.nixos-operations-script.enable = true;
+    ${namespace}.nix.nixos-operations-script.enable = true;
 
     # Pull and apply updates.
     systemd = {

modules/nixos/system/nix/default.nix

@@ -10,23 +10,21 @@
 }:
 
 let
-  cfg = config.${namespace};
+  cfg = config.${namespace}.nix;
 
   nixos-operations-script = pkgs.writeShellScriptBin "nixos-operations-script" (
     builtins.readFile (lib.snowfall.fs.get-file "bin/nixos-operations-script.sh")
   );
 in
 {
-  options = {
+  options.${namespace}.nix = {
-    ${namespace} = {
+    retention = lib.mkOption {
-      retentionPeriod = lib.mkOption {
+      description = "How long to retain NixOS generations. Defaults to two weeks.";
-        description = "How long to retain NixOS generations. Defaults to one month.";
       type = lib.types.str;
-        default = "monthly";
+      default = "14d";
     };
     nixos-operations-script.enable = lib.mkEnableOption "Installs the nos (nixos-operations-script) helper script.";
   };
-  };
   config = lib.mkMerge [
     {
       nix = {
@@ -82,7 +80,7 @@ in
         gc = {
           automatic = true;
           dates = "weekly";
-          options = "--delete-older-than ${cfg.retentionPeriod}";
+          options = "--delete-older-than ${cfg.retention}";
           persistent = true;
           randomizedDelaySec = "1hour";
         };

systems/x86_64-linux/Hevana/default.nix

@@ -114,9 +114,6 @@ in
       mailAddr = config.secrets.users.aires.email;
     };
 
-    # Change how long old generations are kept for.
-    retentionPeriod = "30d";
-
     services = {
       acme = {
         enable = true;

systems/x86_64-linux/Khanda/default.nix

@@ -41,9 +41,6 @@ in
     # Enable support for primary RAID array (just in case)
     raid.storage.enable = true;
 
-    # Change how long old generations are kept for.
-    retentionPeriod = "14d";
-
     services = {
       autoUpgrade = {
         enable = true;

systems/x86_64-linux/Shura/default.nix

@@ -55,8 +55,8 @@ in
     # Enable support for primary RAID array (just in case)
     raid.storage.enable = true;
 
-    # Keep old generations for two weeks.
+    # Keep one week of generations.
-    retentionPeriod = "14d";
+    nix.retention = "7d";
 
     powerManagement.enable = true;