Add opt to set default grpc scheme to passthrough

See merge request !900

Co-authored-by: Malte Bauch <malte.bauch@h-da.de>

cli/cmd/root.go

@@ -36,6 +36,7 @@ import (
 	"os"
 
 	"code.fbi.h-da.de/danet/gosdn/cli/adapter"
+	"google.golang.org/grpc/resolver"
 
 	"github.com/google/uuid"
 	log "github.com/sirupsen/logrus"
@@ -45,6 +46,7 @@ import (
 
 var cfgFile string
 var verbose bool
+var gRPCPassthrough bool
 var loglevel string
 var grpcPort string
 var cliPnd string
@@ -85,6 +87,7 @@ func init() {
 	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (./.gosdnc.toml)")
 	rootCmd.PersistentFlags().StringVarP(&loglevel, "log-level", "l", "", "log level 'debug' or 'trace'")
 	rootCmd.PersistentFlags().BoolVar(&verbose, "verbose", false, "show mne and sbi info")
+	rootCmd.PersistentFlags().BoolVar(&gRPCPassthrough, "grpcPassthrough", true, "set the default resolve scheme for grpc to passthrough, default is true")
 
 	rootCmd.Flags().StringVar(&grpcPort, "grpc-port", "55055", "port for gRPC NBI")
 }
@@ -147,6 +150,13 @@ func initConfig() {
 		cliPnd = uuid.New().String()
 	}
 
+	if gRPCPassthrough {
+		log.Info("Setting gRPC default resolver scheme to passthrough. No DNS queries are being made when doing a gRPC request.")
+		resolver.SetDefaultScheme("passthrough")
+	} else {
+		log.Info("gRPC default resolver scheme is not set to passthrough. This might cause issues with the gRPC connection when no real DNS server is available as each gRPC requests requires a DNS request.")
+	}
+
 	adapter, err := adapter.NewPndAdapter(cliPnd, viper.GetString("controllerAPIEndpoint"))
 	if err != nil {
 		log.Fatal(err)

controller/cmd/root.go

@@ -52,6 +52,7 @@ var csbiOrchestrator string
 var pluginRegistry string
 var pluginFolder string
 var security string
+var gRPCPassthrough bool
 
 // rootCmd represents the base command when called without any subcommands.
 var rootCmd = &cobra.Command{
@@ -86,6 +87,7 @@ func init() {
 	rootCmd.Flags().StringVar(&pluginRegistry, "plugin-registry", "", "plugin registry address")
 	rootCmd.Flags().StringVar(&pluginFolder, "plugin-folder", "", "folder holding all goSDN specific plugins")
 	rootCmd.Flags().StringVarP(&security, "security", "s", "", "security level 'secure' or 'insecure'")
+	rootCmd.Flags().BoolVar(&gRPCPassthrough, "grpcPassthrough", true, "set the default resolve scheme for grpc to passthrough, default is true")
 }
 
 const (

controller/controller.go

@@ -18,6 +18,7 @@ import (
 	"golang.org/x/crypto/argon2"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/resolver"
 
 	apppb "code.fbi.h-da.de/danet/gosdn/api/go/gosdn/app"
 	cmpb "code.fbi.h-da.de/danet/gosdn/api/go/gosdn/configurationmanagement"
@@ -201,6 +202,14 @@ func setupPluginRegistryClient() rpb.PluginRegistryServiceClient {
 }
 
 func startGrpc() error {
+	passthrough := viper.GetBool("passthrough")
+	if passthrough {
+		log.Info("Setting gRPC default resolver scheme to passthrough. No DNS queries are being made when doing a gRPC request.")
+		resolver.SetDefaultScheme("passthrough")
+	} else {
+		log.Info("gRPC default resolver scheme is not set to passthrough. This might cause issues with the gRPC connection when no real DNS server is available as each gRPC requests requires a DNS request.")
+	}
+
 	socket := viper.GetString("socket")
 	lislisten, err := net.Listen("tcp", socket)
 	if err != nil {