ngclient: Create directories as needed

Make sure ngclient creates metadata and artifact directories
when needed.

This was not useful when caller needed to populate the metadata dir with
the initial root anyway, but now with boostrap argument it becomes a
usability improvement.

Signed-off-by: Jussi Kukkonen <jkukkonen@google.com>

Author: jku

examples/client/client

@@ -38,9 +38,6 @@ def init_tofu(base_url: str) -> bool:
 
     metadata_dir = build_metadata_dir(base_url)
 
-    if not os.path.isdir(metadata_dir):
-        os.makedirs(metadata_dir)
-
     response = urllib3.request("GET", f"{base_url}/metadata/1.root.json")
     if response.status != 200:
         print(f"Failed to download initial root {base_url}/metadata/1.root.json")
@@ -81,9 +78,6 @@ def download(base_url: str, target: str) -> bool:
 
     print(f"Using trusted root in {metadata_dir}")
 
-    if not os.path.isdir(DOWNLOAD_DIR):
-        os.mkdir(DOWNLOAD_DIR)
-
     try:
         # NOTE: initial root should be provided with ``bootstrap``  argument:
         # This examples uses unsafe Trust-On-First-Use initialization so it is

tests/test_updater_top_level_update.py

@@ -12,6 +12,7 @@
 import tempfile
 import unittest
 from datetime import timezone
+from pathlib import Path
 from typing import TYPE_CHECKING
 from unittest.mock import MagicMock, call, patch
 
@@ -57,8 +58,6 @@ def setUp(self) -> None:
         self.temp_dir = tempfile.TemporaryDirectory()
         self.metadata_dir = os.path.join(self.temp_dir.name, "metadata")
         self.targets_dir = os.path.join(self.temp_dir.name, "targets")
-        os.mkdir(self.metadata_dir)
-        os.mkdir(self.targets_dir)
 
         self.sim = RepositorySimulator()
 
@@ -134,7 +133,8 @@ def test_cached_root_missing_without_bootstrap(self) -> None:
             self._run_refresh(skip_bootstrap=True)
 
         # Metadata dir is empty
-        self.assertFalse(os.listdir(self.metadata_dir))
+        with self.assertRaises(FileNotFoundError):
+            os.listdir(self.metadata_dir)
 
     def test_trusted_root_expired(self) -> None:
         # Create an expired root version
@@ -166,6 +166,7 @@ def test_trusted_root_expired(self) -> None:
 
     def test_trusted_root_unsigned_without_bootstrap(self) -> None:
         # Cached root is not signed, bootstrap root is not used
+        Path(self.metadata_dir).mkdir(parents=True)
         root_path = os.path.join(self.metadata_dir, "root.json")
         md_root = Metadata.from_bytes(self.sim.signed_roots[0])
         md_root.signatures.clear()

tuf/ngclient/updater.py

@@ -58,6 +58,7 @@
 import os
 import shutil
 import tempfile
+from pathlib import Path
 from typing import TYPE_CHECKING, cast
 from urllib import parse
 
@@ -267,6 +268,7 @@ def download_target(
 
         if filepath is None:
             filepath = self._generate_target_file_path(targetinfo)
+        Path(filepath).parent.mkdir(exist_ok=True, parents=True)
 
         if target_base_url is None:
             if self._target_base_url is None:
@@ -332,10 +334,9 @@ def _persist_root(self, version: int, data: bytes) -> None:
         The metadata is stored with version prefix (e.g.
         "root_history/1.root.json").
         """
-        rootdir = os.path.join(self._dir, "root_history")
-        with contextlib.suppress(FileExistsError):
-            os.mkdir(rootdir)
-        self._persist_file(os.path.join(rootdir, f"{version}.root.json"), data)
+        rootdir = Path(self._dir, "root_history")
+        rootdir.mkdir(exist_ok=True, parents=True)
+        self._persist_file(str(rootdir / f"{version}.root.json"), data)
 
     def _persist_file(self, filename: str, data: bytes) -> None:
         """Write a file to disk atomically to avoid data loss."""