container: Do not leave stale temporary dirs

Do not leave stale temporary directories when conversion fails
unexpectedly. Instead, wrap the conversion operation in a context
manager that wipes the temporary dir afterwards.

Fixes #317

dangerzone/isolation_provider/container.py

@@ -2,6 +2,7 @@
 import json
 import logging
 import os
+import pathlib
 import pipes
 import platform
 import shutil
@@ -217,6 +218,37 @@ def _convert(
  document: Document,
  ocr_lang: Optional[str],
  stdout_callback: Optional[Callable] = None,
+ ) -> bool:
+ # This path needs to be permanent, and may already exist from previous runs.
+ os.makedirs(self.cache_dir, exist_ok=True)
+
+ # Create a temporary directory inside the cache directory for this run. Then,
+ # create some subdirectories for the various stages of the file conversion:
+ #
+ # * pixel: Where the RGB data will be stored
+ # * safe: Where the final PDF file will be stored
+ with tempfile.TemporaryDirectory(dir=self.cache_dir) as tmp_dir:
+ tmp_dir = pathlib.Path(tmp_dir)
+ pixel_dir = tmp_dir / "pixels"
+ pixel_dir.mkdir()
+ safe_dir = tmp_dir / "safe"
+ safe_dir.mkdir()
+
+ return self._convert_with_tmpdirs(
+ document=document,
+ pixel_dir=pixel_dir,
+ safe_dir=safe_dir,
+ ocr_lang=ocr_lang,
+ stdout_callback=stdout_callback,
+ )
+
+ def _convert_with_tmpdirs(
+ self,
+ document: Document,
+ pixel_dir: pathlib.Path,
+ safe_dir: pathlib.Path,
+ ocr_lang: Optional[str],
+ stdout_callback: Optional[Callable] = None,
  ) -> bool:
  success = False
 
@@ -225,15 +257,6 @@ def _convert(
  else:
  ocr = "0"
 
- dz_tmp = os.path.join(self.cache_dir, "tmp")
- os.makedirs(dz_tmp, exist_ok=True)
-
- tmpdir = tempfile.TemporaryDirectory(dir=dz_tmp)
- pixel_dir = os.path.join(tmpdir.name, "pixels")
- safe_dir = os.path.join(tmpdir.name, "safe")
- os.makedirs(pixel_dir, exist_ok=True)
- os.makedirs(safe_dir, exist_ok=True)
-
  # Convert document to pixels
  command = [
  "/usr/bin/python3",
@@ -284,9 +307,6 @@ def _convert(
  # We did it
  success = True
 
- # Clean up
- tmpdir.cleanup()
-
  return success
 
  def get_max_parallel_conversions(self) -> int:

tests/test_cli.py

@@ -155,6 +155,10 @@ def run_cli(
  if tmp_path is not None:
  os.chdir(cwd)
 
+ if cache_dir.exists():
+ stale_files = list(cache_dir.iterdir())
+ assert not stale_files
+
  return CLIResult.reclass_click_result(result, args)