From 24f34780b61fc82df6507cf95535c3dfc9f78058 Mon Sep 17 00:00:00 2001
From: Matthew Holt <mholt@users.noreply.github.com>
Date: Mon, 31 Aug 2020 13:23:26 -0600
Subject: [PATCH] caddytls: Customize DNS resolvers for DNS challenge with
 Caddyfile

---
 modules/caddytls/acmeissuer.go | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/modules/caddytls/acmeissuer.go b/modules/caddytls/acmeissuer.go
index 07974359493..e413156bd17 100644
--- a/modules/caddytls/acmeissuer.go
+++ b/modules/caddytls/acmeissuer.go
@@ -220,6 +220,7 @@ func (iss *ACMEIssuer) GetACMEIssuer() *ACMEIssuer { return iss }
 //         alt_tlsalpn_port <port>
 //         eab <key_id> <mac_key>
 //         trusted_roots <pem_files...>
+//         resolvers <dns_servers...>
 //     }
 //
 func (iss *ACMEIssuer) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
@@ -317,6 +318,18 @@ func (iss *ACMEIssuer) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 			case "trusted_roots":
 				iss.TrustedRootsPEMFiles = d.RemainingArgs()
 
+			case "resolvers":
+				if !d.NextArg() {
+					return d.ArgErr()
+				}
+				if iss.Challenges == nil {
+					iss.Challenges = new(ChallengesConfig)
+				}
+				if iss.Challenges.DNS == nil {
+					iss.Challenges.DNS = new(DNSChallengeConfig)
+				}
+				iss.Challenges.DNS.Resolvers = d.RemainingArgs()
+
 			default:
 				return d.Errf("unrecognized ACME issuer property: %s", d.Val())
 			}