Files
siftlode/backend/app/downloads/errors.py
T
peter 37cca723fc fix(downloads): stop a ReDoS title and a fatal thumbnail convert from wedging/killing downloads
Three prod-observed download bugs, root-caused from a frozen prod queue with the
worker pinned at 100% CPU:

- ReDoS in normalize_title: _TRAILING_HASHTAGS had two overlapping unbounded
  quantifiers around the required letter, so a Facebook title with a long hashtag
  cluster that is NOT at the end ("... #a #b #c | Page") backtracked catastrophically.
  It runs inside the yt-dlp progress hook holding the GIL, so one such download froze
  the whole worker (and could stall feed enrichment too - sync/videos.py calls it).
  Rewrite with a zero-width "has a letter" lookahead + a possessive tag body: one
  unambiguous split, nothing to backtrack. 40-tag stress case: ~0.1ms.

- Reddit download killed by a cosmetic thumbnail convert: yt-dlp's
  FFmpegThumbnailsConvertor runs "-bsf:v mjpeg2jpeg" on a JPEG-served-under-a-.png-name
  (Reddit) and fails; being a postprocessor, it failed the WHOLE download even though
  the media was fine. Drop it and produce the <base>.jpg poster/og:image ourselves via
  editmod.thumbnail_to_jpg (plain ffmpeg decode->mjpeg, best-effort -> ensure_poster
  cuts a frame on failure). The FB Messenger / MS Teams share preview keeps working
  (posters verified as real JPEGs).

- classify: map "authentication is required" (Reddit's auth wall) to login_required
  instead of unknown, so the UI explains it rather than offering a pointless retry.

Tests: ReDoS-timing + numeric-marker regression, the Reddit classify case, and
thumbnail_to_jpg (real JPEG out / None on bad input, never raises).
2026-08-12 18:27:35 +02:00

81 lines
3.8 KiB
Python

"""Classify a raw yt-dlp / ffmpeg failure string into a stable category code.
The worker stores the raw exception text (truncated) for technical detail, but a raw
`ERROR: [youtube] <id>: Private video. Sign in…` is noise to a user. `classify()` maps that text
to one of a small set of category codes; the frontend turns the code into a localized, human
explanation (and decides whether a retry makes sense). The raw text stays available behind a
"details" disclosure. This is the same string-matching approach the worker already trusts for
`_RETRIABLE_MARKERS` — kept here as the single source of truth for "what kind of failure is this".
"""
# (marker, category) — first match wins, so order most-specific → most-general. Matching is
# case-insensitive on a substring, against the raw yt-dlp/ffmpeg message.
_RULES: tuple[tuple[str, str], ...] = (
# Login / age / members / bot-check — the user must be signed in (we deliberately are not).
("sign in to confirm your age", "login_required"),
("confirm your age", "login_required"),
("sign in to confirm you're not a bot", "login_required"),
("not a bot", "login_required"),
("sign in to confirm", "login_required"),
("members-only", "login_required"),
("available to this channel's members", "login_required"),
("join this channel", "login_required"),
("this video is only available to", "login_required"),
# Some extractors (e.g. Reddit) gate content behind a logged-in account: "Account
# authentication is required." — an auth wall we deliberately don't cross, not a transient error.
("authentication is required", "login_required"),
("account authentication", "login_required"),
# Geo-restricted.
("in your country", "geo_blocked"),
("available in your location", "geo_blocked"),
("not available from your location", "geo_blocked"),
("geo restricted", "geo_blocked"),
# An edit's source download went away — our own wording, and MORE specific than the generic
# "no longer available" below, so it must be matched first.
("source download is no longer available", "source_missing"),
("source file is missing", "source_missing"),
# Private / deleted / removed / terminated.
("private video", "unavailable"),
("video unavailable", "unavailable"),
("no longer available", "unavailable"),
("has been removed", "unavailable"),
("removed by the uploader", "unavailable"),
("account associated with this video has been terminated", "unavailable"),
("this video is not available", "unavailable"),
("this video has been removed", "unavailable"),
# DRM.
("drm protected", "drm"),
("drm-protected", "drm"),
# No usable media format.
("requested format is not available", "format_unavailable"),
("only images are available", "format_unavailable"),
("no video formats found", "format_unavailable"),
("unable to extract", "format_unavailable"),
# Our own post-processing (ffmpeg) step failed.
("ffmpeg failed", "postprocess"),
("ffmpeg stalled", "postprocess"),
("postprocessing", "postprocess"),
("produced no output file", "postprocess"),
("no output file", "postprocess"),
# Network / transport.
("unable to download", "network"),
("http error", "network"),
("timed out", "network"),
("read timed out", "network"),
("temporary failure in name resolution", "network"),
("connection reset", "network"),
("connection refused", "network"),
("failed to resolve", "network"),
)
def classify(msg: str | None) -> str:
"""Return a category code for a raw failure message (``"unknown"`` if nothing matches)."""
if not msg:
return "unknown"
low = msg.lower()
for marker, category in _RULES:
if marker in low:
return category
return "unknown"