From af614b53d1e1662c2ecf8f207a1a36bf3d4b0a91 Mon Sep 17 00:00:00 2001
From: Marco Rebhan <me@dblsaiko.net>
Date: Sun, 25 Jun 2023 14:45:08 +0200
Subject: [PATCH] nixos/avahi: Add package option

Allows replacing the avahi package (e.g. for debugging) without having
to use an overlay, avoiding unnecessary package rebuilds.
---
 .../services/networking/avahi-daemon.nix        | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/nixos/modules/services/networking/avahi-daemon.nix b/nixos/modules/services/networking/avahi-daemon.nix
index 3a7519c7230b..bdbf9aad9acc 100644
--- a/nixos/modules/services/networking/avahi-daemon.nix
+++ b/nixos/modules/services/networking/avahi-daemon.nix
@@ -56,6 +56,15 @@ in
       '';
     };
 
+    package = mkOption {
+      type = types.package;
+      default = pkgs.avahi;
+      defaultText = literalExpression "pkgs.avahi";
+      description = lib.mdDoc ''
+        The avahi package to use for running the daemon.
+      '';
+    };
+
     hostName = mkOption {
       type = types.str;
       default = config.networking.hostName;
@@ -260,7 +269,7 @@ in
       (mkAfter [ "mdns" ]) # after dns
     ]);
 
-    environment.systemPackages = [ pkgs.avahi ];
+    environment.systemPackages = [ cfg.package ];
 
     environment.etc = (mapAttrs'
       (n: v: nameValuePair
@@ -286,19 +295,19 @@ in
       # return a sensible value.
       environment.LD_LIBRARY_PATH = config.system.nssModules.path;
 
-      path = [ pkgs.coreutils pkgs.avahi ];
+      path = [ pkgs.coreutils cfg.package ];
 
       serviceConfig = {
         NotifyAccess = "main";
         BusName = "org.freedesktop.Avahi";
         Type = "dbus";
-        ExecStart = "${pkgs.avahi}/sbin/avahi-daemon --syslog -f ${avahiDaemonConf}";
+        ExecStart = "${cfg.package}/sbin/avahi-daemon --syslog -f ${avahiDaemonConf}";
         ConfigurationDirectory = "avahi/services";
       };
     };
 
     services.dbus.enable = true;
-    services.dbus.packages = [ pkgs.avahi ];
+    services.dbus.packages = [ cfg.package ];
 
     networking.firewall.allowedUDPPorts = mkIf cfg.openFirewall [ 5353 ];
   };