feat(home-manager): create timer unit

modules/home-manager.nix

@@ -11,8 +11,8 @@ in
       Unit.Description = "ssh-cert-dist service for ${path}";
       Service = {
         Environment = "RUST_LOG=debug";
-        ExecStart = toString (pkgs.writeShellApplication {
+        ExecStart = "${pkgs.writeShellApplication {
-          name = "ssh-cert-dist-${options.name}";
+          name = "sshcd";
           runtimeInputs = [ cfg.package ];
           text = ''
             ${optionalString options.fetch ''
@@ -22,11 +22,23 @@ in
              sshcd upload --api-endpoint '${cfg.endpoint}' ${path}/*
             ''}
           '';
-        });
+        }}/bin/sshcd";
       };
     };
     })
     cfg.directories);
+  config.systemd.user.timers = mkIf cfg.enable (mapAttrs'
+    (path: options: {
+      inherit (options) name; value = {
+      Unit.Description = "ssh-cert-dist service for ${path}";
+      Timer = {
+        OnCalendar = options.interval;
+        Unit = "${options.name}.service";
+      };
+      Install.WantedBy = [ "timers.target" ];
+    };
+    })
+    cfg.directories);
   config.home.sessionVariables = mkIf (cfg.enable && cfg.endpoint != null) {
     SSH_CD_API = cfg.endpoint;
   };

modules/options.nix

@@ -13,6 +13,11 @@
         type = types.bool;
         default = false;
       };
+      interval = mkOption {
+        type = types.str;
+        default = "daily";
+        description = "https://www.freedesktop.org/software/systemd/man/systemd.time.html";
+      };
     };
   };
   endpointOption = mkOption {