fix: add workaround for Windows permissions error

We were getting errors like `PermissionError: [WinError 5] Access is
denied:
'C:\\Users\\RUNNER~1\\AppData\\Local\\Temp\\resume.md_k098zhaj\\CrashpadMetrics-active.pma'`
and `Exception ignored in: <finalize object at 0x16d9e039d60; dead> ...
NotADirectoryError: [WinError 267] The directory name is invalid:
'C:\\Users\\RUNNER~1\\AppData\\Local\\Temp\\resume.md_3aoun3f2\\CrashpadMetrics-active.pma'`
in CI on Windows. See e.g.
https://github.com/mikepqr/resume.md/runs/5172290981 and
https://github.com/mikepqr/resume.md/runs/5172234014.

The root cause was that Chrome creates a file the python process does
not have permission to delete. See
puppeteer/puppeteer#2778. Because
TemporaryDirectory is intended to be used as a context manager there is
no way to prevent it logging an error when cleanup fails.

The fix is to switch to the lower level tempfile.mkdtemp, and make a
good faith attempt to clean it up manually, logging failure at the debug
level (while adding a new --debug option).

A more sophisticated fix would be to backport the new
ignore_cleanup_errors option added in python 3.10
(python/cpython#24793), but this will do.

Fixes #13

.github/workflows/build.yml

@@ -4,8 +4,6 @@ on:
     workflow_dispatch:
     pull_request:
     push:
-        branches:
-            main
 
 jobs:
   build:
@@ -21,7 +19,7 @@ jobs:
     - name: Install markdown
       run: pip3 install markdown
     - name: Make resume
-      run: python3 resume.py
+      run: python3 resume.py --debug
     - name: Rename output
       if: ${{ matrix.os != 'windows-latest' }}
       run: |

resume.py

@@ -120,7 +120,6 @@ def write_pdf(html: str, prefix: str = "resume", chrome: str = "") -> None:
     Write html to prefix.pdf
     """
     chrome = chrome or guess_chrome_path()
-
     html64 = base64.b64encode(html.encode("utf-8"))
     options = [
         "--headless",
@@ -132,9 +131,18 @@ def write_pdf(html: str, prefix: str = "resume", chrome: str = "") -> None:
     if sys.platform == "win32":
         options.append("--disable-gpu")
 
-    tmpdir = tempfile.TemporaryDirectory(prefix="resume.md_")
-    options.append(f"--crash-dumps-dir={tmpdir.name}")
-    options.append(f"--user-data-dir={tmpdir.name}")
+    # Ideally we'd use tempfile.TemporaryDirectory here. We can't because
+    # attempts to delete the tmpdir fail on Windows because Chrome creates a
+    # file the python process does not have permission to delete. See
+    # https://github.com/puppeteer/puppeteer/issues/2778,
+    # https://github.com/puppeteer/puppeteer/issues/298, and
+    # https://bugs.python.org/issue26660. If we ever drop Python 3.9 support we
+    # can use TemporaryDirectory with ignore_cleanup_errors=True as a context
+    # manager.
+    tmpdir = tempfile.mkdtemp(prefix="resume.md_")
+    options.append(f"--crash-dumps-dir={tmpdir}")
+    options.append(f"--user-data-dir={tmpdir}")
+
     try:
         subprocess.run(
             [
@@ -155,14 +163,9 @@ def write_pdf(html: str, prefix: str = "resume", chrome: str = "") -> None:
         else:
             raise exc
     finally:
-        # We use this try-finally rather than TemporaryDirectory's context
-        # manager to be able to catch the exception caused by
-        # https://bugs.python.org/issue26660 on Windows
-        try:
-            shutil.rmtree(tmpdir.name)
-        except PermissionError as exc:
-            logging.warning(f"Could not delete {tmpdir.name}")
-            logging.info(exc)
+        shutil.rmtree(tmpdir, ignore_errors=True)
+        if os.path.isdir(tmpdir):
+            logging.debug(f"Could not delete {tmpdir}")
 
 
 if __name__ == "__main__":
@@ -188,10 +191,13 @@ def write_pdf(html: str, prefix: str = "resume", chrome: str = "") -> None:
         help="Path to Chrome or Chromium executable",
     )
     parser.add_argument("-q", "--quiet", action="store_true")
+    parser.add_argument("--debug", action="store_true")
     args = parser.parse_args()
 
     if args.quiet:
         logging.basicConfig(level=logging.WARN, format="%(message)s")
+    elif args.debug:
+        logging.basicConfig(level=logging.DEBUG, format="%(message)s")
     else:
         logging.basicConfig(level=logging.INFO, format="%(message)s")