iso: dilter out al profiles (except core)

IN order to avoid random startup of systemd services, filter out all
profiles, except for core and user profiles.

This works becasue of a fundamental devos contract, that modules
only define configuration, but don't implement them and profiles
only implement confguration but don't define them. So only ever an
activated profile is expected to effectively start up a systemd service.

closes: divnix#194

Author: David Arnold

lib/devos/devosSystem.nix

@@ -12,7 +12,11 @@ lib.nixosSystem (args // {
         (args // {
           modules = moduleList ++ [
             "${nixos}/${modpath}/${cd}"
-            ({ config, ... }: {
+            ({ config, suites, ... }: {
+
+              # avoid unwanted systemd service startups
+              disabledModules = suites.allProfilesButCore;
+
               isoImage.isoBaseName = "nixos-" + config.networking.hostName;
               isoImage.contents = [{
                 source = self;

suites/default.nix

@@ -8,6 +8,11 @@ let
   allProfiles =
     let defaults = lib.collect (x: x ? default) profiles;
     in map (x: x.default) defaults;
+  allProfilesButCore = let
+    p = n: _: n != "core";
+    withoutCore = lib.filterAttrs p profiles;
+    defaults = lib.collect (x: x ? default) withoutCore;
+  in map (x: x.default) defaults;
 
   allUsers =
     let defaults = lib.collect (x: x ? default) users;
@@ -19,5 +24,5 @@ let
   };
 in
 lib.mapAttrs (_: v: dev.os.profileMap v) suites // {
-  inherit allProfiles allUsers;
+  inherit allProfiles allUsers allProfilesButCore;
 }