zones: make zonefiles available as packages

krebs/3modules/zones.nix

@@ -1,22 +1,36 @@
 with import <stockholm/lib>;
-{ config, ... }: {
+{ config, pkgs, ... }: {
 
   config = {
-    # Implements environment.etc."zones/<zone-name>"
+    environment.etc =
-    environment.etc = let
-      stripEmptyLines = s: (concatStringsSep "\n"
-        (remove "\n" (remove "" (splitString "\n" s)))) + "\n";
-      all-zones = foldAttrs (sum: current: sum + "\n" +current ) ""
-        ([config.krebs.zone-head-config] ++ combined-hosts);
-      combined-hosts =
-        mapAttrsToList (name: getAttr "extraZones") config.krebs.hosts;
-    in
       mapAttrs'
-        (name: value: {
+        (name: pkg: {
           name = "zones/${name}";
-          value.text = stripEmptyLines value;
+          value.source = pkg;
         })
-        all-zones;
+        pkgs.krebs.zones;
+
+    nixpkgs.overlays = [
+      # Explicit zones generated from config.krebs.hosts.*.extraZones
+      (self: super: let
+        stripEmptyLines = s: (concatStringsSep "\n"
+          (remove "\n" (remove "" (splitString "\n" s)))) + "\n";
+        all-zones = foldAttrs (sum: current: sum + "\n" + current) ""
+          ([config.krebs.zone-head-config] ++ combined-hosts);
+        combined-hosts =
+          mapAttrsToList (name: getAttr "extraZones") config.krebs.hosts;
+      in {
+        krebs = super.krebs or {} // {
+          zones = super.krebs.zones or {} //
+            mapAttrs'
+              (name: value: {
+                name = name;
+                value = self.writeText "${name}.zone" (stripEmptyLines value);
+              })
+              all-zones;
+        };
+      })
+    ];
   };
 
 }