atop: Add basic config option for /etc/atoprc

modules/module-list.nix

@@ -36,6 +36,7 @@
   ./misc/nixpkgs.nix
   ./misc/passthru.nix
   ./misc/version.nix
+  ./programs/atop.nix
   ./programs/bash/bash.nix
   ./programs/bash/command-not-found.nix
   ./programs/blcr.nix

modules/programs/atop.nix

@@ -0,0 +1,36 @@
+# Global configuration for atop.
+
+{config, pkgs, ...}:
+
+with pkgs.lib;
+
+let cfg = config.programs.atop;
+
+in
+{
+  ###### interface
+
+  options = {
+
+    programs.atop = {
+
+      settings = mkOption {
+        type = types.attrs;
+        default = {};
+        example = {
+          flags = "a1f";
+          interval = 5;
+        };
+        description = ''
+          Parameters to be written to <filename>/etc/atoprc</filename>
+        '';
+      };
+
+    };
+  };
+
+  config = mkIf (cfg.settings != {}) {
+    environment.etc."atoprc".text =
+      concatStrings (mapAttrsToList (n: v: "${n} ${toString v}\n") cfg.settings);
+  };
+}