make clamav a module

default.nix

@@ -82,6 +82,7 @@ in
         mkpasswd -m sha-512 "super secret password"
         ```
       '';
+      default = {};
     };
 
     valiases = mkOption {
@@ -98,6 +99,7 @@ in
         forwarded to some valid email address. (Alternatively you can create login
         accounts for `postmaster` and (or) `abuse`).
       '';
+      default = {};
     };
 
     vmail_id_start = mkOption {
@@ -245,12 +247,16 @@ in
     };
   };
 
+  imports = [
+    ./mail-server/clamav.nix
+  ];
+
   config = mkIf cfg.enable {
     services = import ./mail-server/services.nix {
       inherit lib;
       inherit (cfg) mail_dir vmail_user_name vmail_group_name valiases domain
-              enable_imap enable_pop3 virus_scanning dkim_signing dkim_selector
-              dkim_dir certificate_scheme cert_file key_file cert_dir;
+              enable_imap enable_pop3 dkim_signing dkim_selector dkim_dir
+              certificate_scheme cert_file key_file cert_dir virus_scanning;
     };
 
     environment = import ./mail-server/environment.nix {

mail-server/clamav.nix

@@ -14,10 +14,15 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ virus_scanning }:
+{ config, pkgs, lib, ... }:
 
+let
+  cfg = config.mailserver;
+in
 {
-  daemon.enable = virus_scanning;
-  updater.enable = virus_scanning;
+  config = lib.mkIf cfg.virus_scanning {
+    services.clamav.daemon.enable = true;
+    services.clamav.updater.enable = true;
+  };
 }
 

mail-server/services.nix

@@ -51,8 +51,4 @@ in
     inherit vmail_group_name vmail_user_name mail_dir enable_imap
             enable_pop3 cert key;
   };
-
-  clamav = import ./clamav.nix {
-    inherit virus_scanning;
-  };
 }