3 files changed, 20 insertions, 7 deletions
diff --git a/drive/errors.go b/drive/errors.go
index 465d818..f70f0f0 100644
--- a/drive/errors.go
+++ b/drive/errors.go
@@ -6,7 +6,11 @@ import (
 	"time"
 )
 
-const MaxBackendErrorRetries = 5
+const MaxErrorRetries = 5
+
+func isBackendOrRateLimitError(err error) bool {
+	return isBackendError(err) || isRateLimitError(err)
+}
 
 func isBackendError(err error) bool {
 	if err == nil {
@@ -17,6 +21,15 @@ func isBackendError(err error) bool {
 	return ok && ae.Code >= 500 && ae.Code <= 599
 }
 
+func isRateLimitError(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	ae, ok := err.(*googleapi.Error)
+	return ok && ae.Code == 403
+}
+
 func isTimeoutError(err error) bool {
 	return err == context.Canceled
 }
diff --git a/drive/sync_download.go b/drive/sync_download.go
index 10dfd16..58cd49c 100644
--- a/drive/sync_download.go
+++ b/drive/sync_download.go
@@ -193,7 +193,7 @@ func (self *Drive) downloadRemoteFile(id, fpath string, args DownloadSyncArgs, t
 
 	res, err := self.service.Files.Get(id).Context(ctx).Download()
 	if err != nil {
-		if isBackendError(err) && try < MaxBackendErrorRetries {
+		if isBackendOrRateLimitError(err) && try < MaxErrorRetries {
 			exponentialBackoffSleep(try)
 			try++
 			return self.downloadRemoteFile(id, fpath, args, try)
@@ -231,7 +231,7 @@ func (self *Drive) downloadRemoteFile(id, fpath string, args DownloadSyncArgs, t
 	_, err = io.Copy(outFile, reader)
 	if err != nil {
 		outFile.Close()
-		if try < MaxBackendErrorRetries {
+		if try < MaxErrorRetries {
 			exponentialBackoffSleep(try)
 			try++
 			return self.downloadRemoteFile(id, fpath, args, try)
diff --git a/drive/sync_upload.go b/drive/sync_upload.go
index bb1ab33..261497d 100644
--- a/drive/sync_upload.go
+++ b/drive/sync_upload.go
@@ -270,7 +270,7 @@ func (self *Drive) createMissingRemoteDir(args createMissingRemoteDirArgs) (*dri
 
 	f, err := self.service.Files.Create(dstFile).Do()
 	if err != nil {
-		if isBackendError(err) && args.try < MaxBackendErrorRetries {
+		if isBackendOrRateLimitError(err) && args.try < MaxErrorRetries {
 			exponentialBackoffSleep(args.try)
 			args.try++
 			return self.createMissingRemoteDir(args)
@@ -313,7 +313,7 @@ func (self *Drive) uploadMissingFile(parentId string, lf *LocalFile, args Upload
 
 	_, err = self.service.Files.Create(dstFile).Fields("id", "name", "size", "md5Checksum").Context(ctx).Media(reader, chunkSize).Do()
 	if err != nil {
-		if isBackendError(err) && try < MaxBackendErrorRetries {
+		if isBackendOrRateLimitError(err) && try < MaxErrorRetries {
 			exponentialBackoffSleep(try)
 			try++
 			return self.uploadMissingFile(parentId, lf, args, try)
@@ -354,7 +354,7 @@ func (self *Drive) updateChangedFile(cf *changedFile, args UploadSyncArgs, try i
 
 	_, err = self.service.Files.Update(cf.remote.file.Id, dstFile).Context(ctx).Media(reader, chunkSize).Do()
 	if err != nil {
-		if isBackendError(err) && try < MaxBackendErrorRetries {
+		if isBackendOrRateLimitError(err) && try < MaxErrorRetries {
 			exponentialBackoffSleep(try)
 			try++
 			return self.updateChangedFile(cf, args, try)
@@ -375,7 +375,7 @@ func (self *Drive) deleteRemoteFile(rf *RemoteFile, args UploadSyncArgs, try int
 
 	err := self.service.Files.Delete(rf.file.Id).Do()
 	if err != nil {
-		if isBackendError(err) && try < MaxBackendErrorRetries {
+		if isBackendOrRateLimitError(err) && try < MaxErrorRetries {
 			exponentialBackoffSleep(try)
 			try++
 			return self.deleteRemoteFile(rf, args, try)