Change md5Sum to etag (#4399)

cmd/gateway-gcs.go

@@ -164,19 +164,13 @@ type gcsGateway struct {
 
 // newGCSGateway returns gcs gatewaylayer
 func newGCSGateway(args cli.Args) (GatewayLayer, error) {
-	if len(args) != 1 {
+	if !args.Present() {
 		return nil, fmt.Errorf("ProjectID expected")
 	}
 
-	profile := "default"
-	// TODO: don't know where to set profile yet
-	_ = profile
-
 	endpoint := "storage.googleapis.com"
 	secure := true
-
 	projectID := args.First()
-
 	ctx := context.Background()
 
 	// Creates a client.
@@ -485,8 +479,8 @@ func (l *gcsGateway) PutObject(bucket string, key string, size int64, data io.Re
 		teeReader = io.TeeReader(teeReader, sha256Writer)
 	}
 
-	md5sum := metadata["md5Sum"]
+	md5sum := metadata["etag"]
-	delete(metadata, "md5Sum")
+	delete(metadata, "etag")
 
 	object := l.client.Bucket(bucket).Object(key)
 

cmd/gateway-main.go

@@ -355,18 +355,18 @@ func gatewayMain(ctx *cli.Context, backendType gatewayBackend) {
 	}
 
 	serverAddr := ctx.String("address")
-	endpointAddr := ctx.Args().Get(0)
+	endpointAddr := ctx.Args().First()
 	err := validateGatewayArguments(serverAddr, endpointAddr)
 	fatalIf(err, "Invalid argument")
 
 	// Create certs path for SSL configuration.
 	fatalIf(createConfigDir(), "Unable to create configuration directory")
 
+	initNSLock(false) // Enable local namespace lock.
+
 	newObject, err := newGatewayLayer(backendType, ctx.Args()[1:])
 	fatalIf(err, "Unable to initialize gateway layer")
 
-	initNSLock(false) // Enable local namespace lock.
-
 	router := mux.NewRouter().SkipClean(true)
 
 	// credentials Envs are set globally.
@@ -432,9 +432,12 @@ func gatewayMain(ctx *cli.Context, backendType gatewayBackend) {
 	// Prints the formatted startup message once object layer is initialized.
 	if !quietFlag {
 		mode := ""
-		if gatewayBackend(backendType) == azureBackend {
+		switch gatewayBackend(backendType) {
+		case azureBackend:
 			mode = globalMinioModeGatewayAzure
-		} else if gatewayBackend(backendType) == s3Backend {
+		case gcsBackend:
+			mode = globalMinioModeGatewayGCS
+		case s3Backend:
 			mode = globalMinioModeGatewayS3
 		}
 		checkUpdate(mode)

cmd/globals.go

@@ -40,6 +40,7 @@ const (
 	globalMinioModeDistXL          = "mode-server-distributed-xl"
 	globalMinioModeGatewayAzure    = "mode-gateway-azure"
 	globalMinioModeGatewayS3       = "mode-gateway-s3"
+	globalMinioModeGatewayGCS      = "mode-gateway-gcs"
 	// Add new global values here.
 )