BUG/MINOR: configuration: maintain backward compatibility for scheme

Author: mjuraga

dataplaneapi_generated.go renamed to dataplaneapi_configuration.go

@@ -1,4 +1,3 @@
-// Code generated by go generate; DO NOT EDIT.
 // Copyright 2021 HAProxy Technologies
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -26,9 +25,17 @@ import (
 	"github.com/haproxytech/dataplaneapi/misc"
 )
 
-func SyncWithFileSettings(server *Server, cfg *configuration.Configuration) {
+func SyncWithFileSettings(server *Server, cfg *configuration.Configuration) { //nolint: cyclop
 	configStorage := cfg.GetStorageData()
-	if configStorage.Dataplaneapi != nil && configStorage.Dataplaneapi.EnabledListeners != nil && !misc.HasOSArg("", "scheme", "") {
+	// This is added to allow backward compatibility if no scheme is defined it defaults to specification schemes
+	// and recently we added https to specification for clarity, and then old configs without scheme in them would
+	// start to fail.
+	if len(server.EnabledListeners) == 0 && configStorage.Dataplaneapi != nil {
+		if configStorage.Dataplaneapi.EnabledListeners == nil {
+			configStorage.Dataplaneapi.EnabledListeners = &[]string{"http"}
+		}
+	}
+	if configStorage.Dataplaneapi.EnabledListeners != nil && !misc.HasOSArg("", "scheme", "") {
 		server.EnabledListeners = *configStorage.Dataplaneapi.EnabledListeners
 	}
 	if configStorage.Dataplaneapi != nil && configStorage.Dataplaneapi.CleanupTimeout != nil && !misc.HasOSArg("", "cleanup-timeout", "") {