Fix for Caddy's documentation generator

Caddy's documentation generator doesn't work with generics, nor with
custom JSON representations.

Author: liujed

dns_config.go

@@ -6,7 +6,6 @@ import (
 
 	"github.com/caddyserver/caddy/v2"
 	"github.com/caddyserver/certmagic"
-	"github.com/liujed/goutil/optionals"
 )
 
 type DNSConfig struct {
@@ -15,7 +14,11 @@ type DNSConfig struct {
 	Provider certmagic.DNSProvider `json:"-"`
 
 	// The TTL to use for the DNS TXT records when answering challenges.
-	TTL optionals.Optional[caddy.Duration] `json:"ttl"`
+	//
+	// XXX This should be an Optional[caddy.Duration], but Caddy's documentation
+	// generator can handle neither generics nor types with custom JSON
+	// representations.
+	TTL *caddy.Duration `json:"ttl,omitempty"`
 
 	// Custom DNS resolvers to prefer over system/built-in defaults. Often
 	// necessary to configure when using split-horizon DNS.

handler.go

@@ -209,9 +209,9 @@ func (h *Handler) handleDNSRequest(
 		}
 
 		// Build the DNS record to create/delete.
-		ttl := time.Duration(h.DNS.TTL.GetOrDefault(0))
-		if mode == hmCleanup {
-			ttl = 0
+		ttl := time.Duration(0)
+		if mode != hmCleanup && h.DNS.TTL != nil {
+			ttl = time.Duration(*h.DNS.TTL)
 		}
 		records := []libdns.Record{
 			libdns.TXT{
@@ -297,7 +297,8 @@ func (h *Handler) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 			if err != nil {
 				return err
 			}
-			h.DNS.TTL = optionals.Some(caddy.Duration(parsedTTL))
+			caddyTTL := caddy.Duration(parsedTTL)
+			h.DNS.TTL = &caddyTTL
 
 		case "resolvers":
 			h.DNS.Resolvers = d.RemainingArgs()