From ec8b458d751a4075aab09ec3995385baf70fc383 Mon Sep 17 00:00:00 2001
From: Brendan Golden <git_laptop@brendan.ie>
Date: Sat, 29 Apr 2023 01:54:17 +0100
Subject: [PATCH] dns: use a hash to make a unique config file

---
 applications/dns.nix | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/applications/dns.nix b/applications/dns.nix
index 44003af..03a8dfa 100644
--- a/applications/dns.nix
+++ b/applications/dns.nix
@@ -6,6 +6,16 @@ let
   current_date_path = pkgs.runCommand "current_date" {} "date '+%s' > $out";
   # reads that date to a string
   current_date = (lib.readFile current_date_path);
+
+  # get all the records as a string (used later in teh zone file)
+  current_external = lib.strings.concatMapStrings (x: x + "\n") cfg.records.external;
+  current_cname = lib.strings.concatMapStrings (x: x + "\n") cfg.records.cname;
+
+  # get a hash of these two (cut down into a more manageable size)
+  current_hash = lib.substring 0 10 (builtins.hashString "md5" "${current_external}_${current_cname}");
+
+  # create a custom filepath
+  current_file = "${current_date}_${current_hash}";
 in {
   options = {
     skynet_dns = {
@@ -136,7 +146,8 @@ in {
           master = true;
           slaves = [ ];
           # need to write this to a file
-          file = "/etc/dns_custom/dns_zone_skynet";
+          # using the date in it so it will trigger a restart
+          file = "/etc/dns_custom/dns_zone_skynet_${current_file}";
           # no leading whitespace for first line
 
         };
@@ -152,7 +163,7 @@ in {
     environment.etc = {
       # Creates /etc/dns_custom/dns_zone_skynet
 
-      "dns_custom/dns_zone_skynet" = {
+      "dns_custom/dns_zone_skynet_${current_file}" = {
         user = "named";
         group = "named";
 
@@ -189,7 +200,7 @@ in {
 
           ; External addresses
           ; ------------------------------------------
-          ${lib.strings.concatMapStrings (x: x + "\n") cfg.records.external}
+          ${current_external}
 
 
           ; this is fixed for now
@@ -204,7 +215,7 @@ in {
 
           ; cname's
           ; ------------------------------------------
-          ${lib.strings.concatMapStrings (x: x + "\n") cfg.records.cname}
+          ${current_cname}
 
           '';
       };