flake.nix: add checks, add checkPhases with nsd-check* tests

flake.nix

@@ -11,7 +11,7 @@
   };
 
   outputs =
-    { nixpkgs, dns, ... }@inputs:
+    { self, nixpkgs, dns, ... }@inputs:
     let
       inherit (nixpkgs) lib;
       systems = [
@@ -27,7 +27,7 @@
           inherit dns;
         };
 
-        nsdConfig = pkgs.callPackage ./nsd.conf.nix { inherit pkgs; };
+        nsdConfig = pkgs.callPackage ./nsd.conf.nix { };
 
         default = pkgs.runCommand "pvv-dns" { } ''
           mkdir -p $out/zones
@@ -37,5 +37,10 @@
           cp -r ${nsdConfig} $out/etc/nsd/nsd.conf
         '';
       });
+
+      checks = forAllSystems (system: _: rec {
+        zoneFiles = self.packages.${system}.zoneFiles.overrideAttrs { doCheck = true; };
+        nsdConfig = self.packages.${system}.nsdConfig.override { doCheck = true; };
+      });
     };
 }

nsd.conf.nix

@@ -1,9 +1,15 @@
-{ pkgs, ... }:
+{
+  lib,
+  writeTextFile,
+  doCheck ? false,
+  nsd,
+}:
 let
   sourceIP = "129.241.210.211"; # dvask.pvv.ntnu.no
 in
-pkgs.writeText "nsd.conf" (
-  ''
+writeTextFile {
+  name = "nsd.conf";
+  text = ''
     # Generated by https://git.pvv.ntnu.no/felixalb/PVV-DNS
     # See man 5 nsd.conf
 
@@ -56,5 +62,7 @@ pkgs.writeText "nsd.conf" (
         "pvv.ntnu.no"
         "pvv.org"
       ]
-  ))
-)
+  ));
+
+  checkPhase = lib.optionalString doCheck "${lib.getExe' nsd "nsd-checkconf"} $target";
+}

zoneConfig.nix

@@ -4,6 +4,7 @@
 
   stdenvNoCC,
   writeText,
+  nsd,
 }:
 
 let
@@ -33,4 +34,14 @@ stdenvNoCC.mkDerivation {
     mkdir -p $out
   ''
   + (lib.concatMapAttrsStringSep "\n" (name: path: "cp ${path} $out/${name}.zone") zoneConfigs);
+
+  doCheck = false;
+  nativeCheckInputs = [ nsd ];
+  checkPhase = ''
+    runHook preCheck
+
+    ${lib.concatMapAttrsStringSep "\n" (name: zonefile: "nsd-checkzone '${name}' '${zonefile}'") zoneConfigs}
+
+    runHook postCheck
+  '';
 }