feat(dns): default serve action port when unset

Co-Authored-By: Virgil <virgil@lethean.io>

action.go

@@ -289,7 +289,7 @@ func (service *Service) handleServe(ctx context.Context, values map[string]any)
 		return nil, false, err
 	}
 	if !portProvided {
-		port = service.dnsPort
+		port = service.resolveServePort()
 	}
 	result, err := service.Serve(bind, port)
 	if err != nil {
@@ -298,6 +298,13 @@ func (service *Service) handleServe(ctx context.Context, values map[string]any)
 	return result, true, nil
 }
 
+func (service *Service) resolveServePort() int {
+	if service == nil || service.dnsPort <= 0 {
+		return DefaultDNSPort
+	}
+	return service.dnsPort
+}
+
 func stringActionValue(values map[string]any, key string) (string, error) {
 	if values == nil {
 		return "", errActionMissingValue

service.go

@@ -18,6 +18,7 @@ import (
 //	service := dns.NewService(dns.ServiceOptions{})
 //	fmt.Println(dns.DefaultTreeRootCheckInterval)
 const DefaultTreeRootCheckInterval = 15 * time.Second
+const DefaultDNSPort = 53
 
 // NameRecords stores the cached DNS records for one name.
 //

service_test.go

@@ -2233,6 +2233,21 @@ func TestServiceHandleActionServeDefaultsPortFromServiceConfiguration(t *testing
 	_ = dnsServer.Close()
 }
 
+func TestServiceResolveServePortDefaultsToStandardDNSPort(t *testing.T) {
+	service := NewService(ServiceOptions{})
+	if service.resolveServePort() != DefaultDNSPort {
+		t.Fatalf("expected serve to default to standard DNS port %d, got %d", DefaultDNSPort, service.resolveServePort())
+	}
+
+	customPort := 1053
+	customService := NewService(ServiceOptions{
+		DNSPort: customPort,
+	})
+	if customService.resolveServePort() != customPort {
+		t.Fatalf("expected resolveServePort to honor configured DNSPort, got %d", customService.resolveServePort())
+	}
+}
+
 func TestServiceActionNamesExposeAllRFCActions(t *testing.T) {
 	service := NewService(ServiceOptions{})
 
@@ -2636,8 +2651,8 @@ func TestServiceDiscoverAliasesFallsBackToMainchainAliasRPCUsingHSDURL(t *testin
 	defer server.Close()
 
 	service := NewService(ServiceOptions{
-		HSDURL:   server.URL,
-		Records:  map[string]NameRecords{},
+		HSDURL:  server.URL,
+		Records: map[string]NameRecords{},
 	})
 
 	if err := service.DiscoverAliases(context.Background()); err != nil {