From c3e75d49314f262d8a9f15aa0070ea6c1794cd18 Mon Sep 17 00:00:00 2001
From: David Warde-Farley <dwf@google.com>
Date: Mon, 26 Sep 2022 02:23:45 +0100
Subject: [PATCH] Use `null` instead of empty string.

Per @aanderse in 7556fd7.
---
 .../services/web-servers/caddy/default.nix    | 31 ++++++++++---------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/nixos/modules/services/web-servers/caddy/default.nix b/nixos/modules/services/web-servers/caddy/default.nix
index 4bd58d9116fb79d..d92fe698c5f6192 100644
--- a/nixos/modules/services/web-servers/caddy/default.nix
+++ b/nixos/modules/services/web-servers/caddy/default.nix
@@ -26,7 +26,7 @@ let
 
   configFile =
     let
-      Caddyfile = pkgs.writeText "Caddyfile" ''
+      Caddyfile = pkgs.writeTextDir "Caddyfile" ''
         {
           ${cfg.globalConfig}
         }
@@ -34,10 +34,11 @@ let
       '';
 
       Caddyfile-formatted = pkgs.runCommand "Caddyfile-formatted" { nativeBuildInputs = [ cfg.package ]; } ''
-        ${cfg.package}/bin/caddy fmt ${Caddyfile} > $out
+        mkdir -p $out
+        ${cfg.package}/bin/caddy fmt ${Caddyfile}/Caddyfile > $out/Caddyfile
       '';
     in
-      if pkgs.stdenv.buildPlatform == pkgs.stdenv.hostPlatform then Caddyfile-formatted else Caddyfile;
+      "${if pkgs.stdenv.buildPlatform == pkgs.stdenv.hostPlatform then Caddyfile-formatted else Caddyfile}/Caddyfile";
 
   acmeHosts = unique (catAttrs "useACMEHost" acmeVHosts);
 
@@ -142,7 +143,7 @@ in
       default = configFile;
       defaultText = "A Caddyfile automatically generated by values from services.caddy.*";
       example = literalExpression ''
-        pkgs.writeText "Caddyfile" '''
+        pkgs.writeTextDir "Caddyfile" '''
           example.com
 
           root * /var/www/wordpress
@@ -157,15 +158,15 @@ in
     };
 
     adapter = mkOption {
-      default = "caddyfile";
+      default = null;
       example = "nginx";
-      type = types.str;
-      description = lib.mdDoc ''
+      type = with types; nullOr str;
+      description = ''
         Name of the config adapter to use.
         See <https://caddyserver.com/docs/config-adapters>
         for the full list.
 
-        If the empty string is specified, the <literal>--adapter</literal>
+        If <literal>null</literal> is specified, the <literal>--adapter</literal>
         argument is omitted when starting or restarting Caddy. Notably, this
         allows specification of a configuration file in Caddy's native JSON
         format, as long as the filename does not start with
@@ -175,8 +176,8 @@ in
         for details.
 
         <note><para>
-          Any value other than <literal>caddyfile</literal> is only valid when
-          providing your own <option>configFile</option>.
+          Any value other than <literal>null</literal> or <literal>caddyfile</literal>
+          is only valid when providing your own <option>configFile</option>.
         </para></note>
       '';
     };
@@ -273,8 +274,8 @@ in
   config = mkIf cfg.enable {
 
     assertions = [
-      { assertion = cfg.adapter != "caddyfile" -> cfg.configFile != configFile;
-        message = "Any value other than 'caddyfile' is only valid when providing your own `services.caddy.configFile`";
+      { assertion = cfg.configFile == configFile -> cfg.adapter == "caddyfile" || cfg.adapter == null;
+        message = "To specify an adapter other than 'caddyfile' please provide your own configuration via `services.caddy.configFile`";
       }
     ] ++ map (name: mkCertOwnershipAssertion {
       inherit (cfg) group user;
@@ -304,9 +305,9 @@ in
       serviceConfig = {
         # https://www.freedesktop.org/software/systemd/man/systemd.service.html#ExecStart=
         # If the empty string is assigned to this option, the list of commands to start is reset, prior assignments of this option will have no effect.
-        ExecStart = [ "" ''${cfg.package}/bin/caddy run --config ${cfg.configFile} ${optionalString (cfg.adapter != "") "--adapter ${cfg.adapter}"} ${optionalString cfg.resume "--resume"}'' ];
-        ExecReload = [ "" ''${cfg.package}/bin/caddy reload --config ${cfg.configFile} ${optionalString (cfg.adapter != "") "--adapter ${cfg.adapter}"} --force'' ];
-        ExecStartPre = ''${cfg.package}/bin/caddy validate --config ${cfg.configFile} ${optionalString (cfg.adapter != "") "--adapter ${cfg.adapter}"}'';
+        ExecStart = [ "" ''${cfg.package}/bin/caddy run --config ${cfg.configFile} ${optionalString (cfg.adapter != null) "--adapter ${cfg.adapter}"} ${optionalString cfg.resume "--resume"}'' ];
+        ExecReload = [ "" ''${cfg.package}/bin/caddy reload --config ${cfg.configFile} ${optionalString (cfg.adapter != null) "--adapter ${cfg.adapter}"} --force'' ];
+        ExecStartPre = ''${cfg.package}/bin/caddy validate --config ${cfg.configFile} ${optionalString (cfg.adapter != null) "--adapter ${cfg.adapter}"}'';
         User = cfg.user;
         Group = cfg.group;
         ReadWriteDirectories = cfg.dataDir;