gphoto2: Add option for group name

nixos/modules/programs/gphoto2.nix

@@ -1,4 +1,9 @@
-{ config, lib, pkgs, ... }:
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
 
 {
   meta.maintainers = [ lib.maintainers.league ];
@@ -9,12 +14,18 @@
       enable = lib.mkOption {
         default = false;
         type = lib.types.bool;
+        description = "Whether to configure system to use gphoto2.";
+      };
+      group = lib.mkOption {
         description = ''
-          Whether to configure system to use gphoto2.
-          To grant digital camera access to a user, the user must
-          be part of the camera group:
-          `users.users.alice.extraGroups = ["camera"];`
+          Group created when gphoto2 is enabled.
+
+          To grant digital camera access to a user, the user must be part of this group:
+          `users.users.alice.extraGroups = [ config.programs.gphoto2.group ];`.
         '';
+        type = lib.types.str;
+        default = "camera";
+        example = "gphoto2";
       };
     };
   };
@@ -23,6 +34,6 @@
   config = lib.mkIf config.programs.gphoto2.enable {
     services.udev.packages = [ pkgs.libgphoto2 ];
     environment.systemPackages = [ pkgs.gphoto2 ];
-    users.groups.camera = {};
+    users.groups."${config.programs.gphoto2.group}" = { };
   };
 }

pkgs/by-name/li/libgphoto2/package.nix

@@ -1,20 +1,25 @@
-{ lib
-, stdenv
-, fetchFromGitHub
-, buildPackages
-, autoreconfHook
-, pkg-config
-, gettext
-, libusb1
-, libtool
-, libexif
-, libgphoto2
-, libjpeg
-, curl
-, libxml2
-, gd
+{
+  lib,
+  nixos,
+  stdenv,
+  fetchFromGitHub,
+  buildPackages,
+  autoreconfHook,
+  pkg-config,
+  gettext,
+  libusb1,
+  libtool,
+  libexif,
+  libgphoto2,
+  libjpeg,
+  curl,
+  libxml2,
+  gd,
 }:
-
+let
+  inherit (nixos { }) config;
+  group = config.programs.gphoto2.group or "camera";
+in
 stdenv.mkDerivation rec {
   pname = "libgphoto2";
   version = "2.5.31";
@@ -56,18 +61,15 @@ stdenv.mkDerivation rec {
   postInstall =
     let
       executablePrefix =
-        if stdenv.buildPlatform == stdenv.hostPlatform then
-          "$out"
-        else
-          buildPackages.libgphoto2;
+        if stdenv.buildPlatform == stdenv.hostPlatform then "$out" else buildPackages.libgphoto2;
     in
     ''
       mkdir -p $out/lib/udev/{rules.d,hwdb.d}
       ${executablePrefix}/lib/libgphoto2/print-camera-list \
-          udev-rules version 201 group camera \
+          udev-rules version 201 group ${group} \
           >$out/lib/udev/rules.d/40-libgphoto2.rules
       ${executablePrefix}/lib/libgphoto2/print-camera-list \
-          hwdb version 201 group camera \
+          hwdb version 201 group ${group} \
           >$out/lib/udev/hwdb.d/20-gphoto.hwdb
     '';