Layer 3 — prevent the hard worker crash rather than just recovering from
it. The realistic process-crash vectors (operator's observed slow/heavy
tasks) are video decode and archive extraction; images decode in-process
and Pillow raises-and-skips cleanly, and a subprocess per image would
wreck deep-scan throughput, so images are intentionally not probed.
New backend/app/utils/safe_probe.py (leaf module, lazy heavy imports so
the spawned child stays light):
- probe_video(path): validates the container + first video stream via
ffprobe (a separate binary — a decoder crash kills only ffprobe, not
the worker). Returns width/height, which the importer didn't capture
for videos before. crashed=True only on ffprobe timeout.
- probe_archive(path): an uncompressed-size bomb guard
(MAX_ARCHIVE_UNCOMPRESSED_BYTES = 4 GiB) plus the format integrity
test (zipfile.testzip / rarfile.testrar / py7zr.test) run in a
spawned child process. A decompression-bomb OOM or native-lib
segfault on a malformed archive shows up as a non-zero child exit
code → crashed=True, never a dead worker.
ProbeResult.crashed distinguishes a HARD failure (subprocess killed /
timed out — the poison-pill signature → caller returns terminal
'failed') from a CLEAN rejection (corrupt-but-handled, bomb cap,
integrity mismatch → caller's choice of skipped/attached).
Wired:
- importer._import_media video branch: probe_video before the pipeline;
crash → failed, clean reject → invalid_image skip, ok → capture dims.
- importer._import_archive: probe_archive before extract_archive; crash
→ failed, clean reject → still preserve the archive as a
PostAttachment (matches extract_archive's fail-soft contract).
- ml.tag_and_embed video branch: probe_video before sampling 10 frames,
so a corrupt video is rejected (status='bad_video') instead of
crashing the ml-worker on frame decode.
Tests (test_safe_probe.py): valid/corrupt zip via probe_archive, direct
_inspect_archive size+integrity, in-process _archive_probe_target bomb
guard (monkeypatch can't reach a spawned child, so the target is called
directly), and a non-video → ok=False that's robust to ffprobe presence
in CI.
bvandeusen
e3cdd0f92b