From cbbabaddf9c2697379f49de6eaf0d7db99db2366 Mon Sep 17 00:00:00 2001
From: CRTified <carl.schneider+github@ruhr-uni-bochum.de>
Date: Wed, 12 Jan 2022 19:19:00 +0100
Subject: [PATCH] nixos/adguardhome: Fix #154775 by checking for settings

---
 .../services/networking/adguardhome.nix        | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/nixos/modules/services/networking/adguardhome.nix b/nixos/modules/services/networking/adguardhome.nix
index 05713adbd83a..98ddf0716087 100644
--- a/nixos/modules/services/networking/adguardhome.nix
+++ b/nixos/modules/services/networking/adguardhome.nix
@@ -87,6 +87,22 @@ in {
   };
 
   config = mkIf cfg.enable {
+    assertions = [
+      {
+        assertion = cfg.settings != { }
+          -> (hasAttrByPath [ "dns" "bind_host" ] cfg.settings)
+          || (hasAttrByPath [ "dns" "bind_hosts" ] cfg.settings);
+        message =
+          "AdGuard setting dns.bind_host or dns.bind_hosts needs to be configured for a minimal working configuration";
+      }
+      {
+        assertion = cfg.settings != { }
+          -> hasAttrByPath [ "dns" "bootstrap_dns" ] cfg.settings;
+        message =
+          "AdGuard setting dns.bootstrap_dns needs to be configured for a minimal working configuration";
+      }
+    ];
+
     systemd.services.adguardhome = {
       description = "AdGuard Home: Network-level blocker";
       after = [ "network.target" ];
@@ -96,7 +112,7 @@ in {
         StartLimitBurst = 10;
       };
 
-      preStart = ''
+      preStart = optionalString (cfg.settings != { }) ''
         if    [ -e "$STATE_DIRECTORY/AdGuardHome.yaml" ] \
            && [ "${toString cfg.mutableSettings}" = "1" ]; then
           # Writing directly to AdGuardHome.yaml results in empty file