httpcaddyfile: Add 'experimental_http3' option

caddyconfig/httpcaddyfile/httptype.go

@@ -64,6 +64,8 @@ func (st ServerType) Setup(originalServerBlocks []caddyfile.ServerBlock,
 				val, err = parseHTTPSPort(caddyfile.NewDispenser(segment))
 			case "handler_order":
 				val, err = parseHandlerOrder(caddyfile.NewDispenser(segment))
+			case "experimental_http3":
+				val, err = parseExperimentalHTTP3(caddyfile.NewDispenser(segment))
 			default:
 				return nil, warnings, fmt.Errorf("unrecognized parameter name: %s", dir)
 			}
@@ -190,6 +192,13 @@ func (st ServerType) Setup(originalServerBlocks []caddyfile.ServerBlock,
 	// consolidate automation policies that are the exact same
 	tlsApp.Automation.Policies = consolidateAutomationPolicies(tlsApp.Automation.Policies)
 
+	// if experimental HTTP/3 is enabled, enable it on each server
+	if enableH3, ok := options["experimental_http3"].(bool); ok && enableH3 {
+		for _, srv := range httpApp.Servers {
+			srv.ExperimentalHTTP3 = true
+		}
+	}
+
 	// annnd the top-level config, then we're done!
 	cfg := &caddy.Config{AppsRaw: make(map[string]json.RawMessage)}
 	if !reflect.DeepEqual(httpApp, caddyhttp.App{}) {

caddyconfig/httpcaddyfile/options.go

@@ -52,6 +52,10 @@ func parseHTTPSPort(d *caddyfile.Dispenser) (int, error) {
 	return httpsPort, nil
 }
 
+func parseExperimentalHTTP3(d *caddyfile.Dispenser) (bool, error) {
+	return true, nil
+}
+
 func parseHandlerOrder(d *caddyfile.Dispenser) ([]string, error) {
 	if !d.Next() {
 		return nil, d.ArgErr()