nixos/netdata: own plugins must the looked up first

Otherwise netdata will not find python modules.
To make sure netdata still pick up our setuid version of apps.plugin
we rename the original executable.

nixos/modules/services/monitoring/netdata.nix

@@ -12,7 +12,7 @@ let
 
   localConfig = {
     global = {
-      "plugins directory" = "${wrappedPlugins}/libexec/netdata/plugins.d ${pkgs.netdata}/libexec/netdata/plugins.d";
+      "plugins directory" = "${pkgs.netdata}/libexec/netdata/plugins.d ${wrappedPlugins}/libexec/netdata/plugins.d";
     };
     web = {
       "web files owner" = "root";
@@ -96,7 +96,7 @@ in {
     };
 
     security.wrappers."apps.plugin" = {
-      source = "${pkgs.netdata}/libexec/netdata/plugins.d/apps.plugin";
+      source = "${pkgs.netdata}/libexec/netdata/plugins.d/apps.plugin.org";
       capabilities = "cap_dac_read_search,cap_sys_ptrace+ep";
       owner = cfg.user;
       group = cfg.group;

pkgs/tools/system/netdata/default.nix

@@ -17,6 +17,12 @@ stdenv.mkDerivation rec{
     ./no-files-in-etc-and-var.patch
   ];
 
+  postInstall = stdenv.lib.optionalString (!stdenv.isDarwin) ''
+    # rename this plugin so netdata will look for setuid wrapper
+    mv $out/libexec/netdata/plugins.d/apps.plugin \
+      $out/libexec/netdata/plugins.d/apps.plugin.org
+  '';
+
   configureFlags = [
     "--localstatedir=/var"
     "--sysconfdir=/etc"