ngclient: simplify storing a downloaded file

Replace the usage of securesystemslib.util.persist_temp_file() with shutil.copyfileobj() as file system abstraction is not used in the client. This way we prevent securesystemslib.exception.StorageError from leaking through client API calls. Note: with those changes we are no longer do fsync. Signed-off-by: Martin Vrachev <[email protected]>
theupdateframework · Jan 27, 2022 · 3fa0668 · 3fa0668
1 parent d95ead6
commit 3fa0668
Showing 1 changed file with 5 additions and 5 deletions.
diff --git a/tuf/ngclient/updater.py b/tuf/ngclient/updater.py
@@ -35,12 +35,11 @@
 
 import logging
 import os
+import shutil
 import tempfile
 from typing import Optional, Set
 from urllib import parse
 
-from securesystemslib import util as sslib_util
-
 from tuf.api import exceptions
 from tuf.api.metadata import (
     Metadata,
@@ -218,8 +217,7 @@ def download_target(
             ValueError: Invalid arguments
             DownloadError: Download of the target file failed in some way
             RepositoryError: Downloaded target failed to be verified in some way
-            exceptions.StorageError: Downloaded target could not be written
-                to disk
+            OSError: Failed to write target to file
 
         Returns:
             Local path to downloaded file
@@ -252,7 +250,9 @@ def download_target(
         ) as target_file:
             targetinfo.verify_length_and_hashes(target_file)
 
-            sslib_util.persist_temp_file(target_file, filepath)
+            target_file.seek(0)
+            with open(filepath, "wb") as destination_file:
+                shutil.copyfileobj(target_file, destination_file)
 
         logger.info("Downloaded target %s", targetinfo.path)
         return filepath