use null server for no op case

Signed-off-by: Periyasamy Palanisamy <[email protected]>

main.go

@@ -173,44 +173,35 @@ func main() {
 	// ********************************************************************************
 	sriovTokens := tokens.FromEnv(os.Environ())
 
-	var additionalFunc endpoint.Option
-	if len(sriovTokens) == 0 {
-		additionalFunc = endpoint.WithAdditionalFunctionality(
-			onidle.NewServer(ctx, cancel, config.IdleTimeout),
-			point2pointipam.NewServer(ipnet),
-			recvfd.NewServer(),
-			mechanisms.NewServer(map[string]networkservice.NetworkServiceServer{
-				kernelmech.MECHANISM: kernel.NewServer(),
-				noop.MECHANISM:       null.NewServer(),
-			}),
-			dnscontext.NewServer(config.DNSConfigs...),
-			sendfd.NewServer(),
-		)
-	} else if len(sriovTokens) == 1 {
+	var tokenServer networkservice.NetworkServiceServer
+	switch len(sriovTokens) {
+	case 0:
+		tokenServer = null.NewServer()
+	case 1:
 		var tokenKey string
 		for tokenKey = range sriovTokens {
 			break
 		}
-		additionalFunc = endpoint.WithAdditionalFunctionality(
+		tokenServer = token.NewServer(tokenKey)
+	default:
+		log.FromContext(ctx).Fatalf("endpoint must be configured with none or only one sriov resource")
+	}
+	responderEndpoint := endpoint.NewServer(ctx,
+		spiffejwt.TokenGeneratorFunc(source, config.MaxTokenLifetime),
+		endpoint.WithName(config.Name),
+		endpoint.WithAuthorizeServer(authorize.NewServer()),
+		endpoint.WithAdditionalFunctionality(
 			onidle.NewServer(ctx, cancel, config.IdleTimeout),
 			point2pointipam.NewServer(ipnet),
 			recvfd.NewServer(),
-			token.NewServer(tokenKey),
 			mechanisms.NewServer(map[string]networkservice.NetworkServiceServer{
 				kernelmech.MECHANISM: kernel.NewServer(),
 				noop.MECHANISM:       null.NewServer(),
 			}),
+			tokenServer,
 			dnscontext.NewServer(config.DNSConfigs...),
 			sendfd.NewServer(),
-		)
-	} else {
-		log.FromContext(ctx).Fatalf("endpoint must be configured with none or only one sriov resource")
-	}
-	responderEndpoint := endpoint.NewServer(ctx,
-		spiffejwt.TokenGeneratorFunc(source, config.MaxTokenLifetime),
-		endpoint.WithName(config.Name),
-		endpoint.WithAuthorizeServer(authorize.NewServer()),
-		additionalFunc,
+		),
 	)
 	// ********************************************************************************
 	log.FromContext(ctx).Infof("executing phase 5: create grpc server and register icmp-server")