Files
siftlode/backend/app/downloads/runner.py
T
peter bc33b2ed16 feat(downloads): per-user, per-host yt-dlp cookie/auth support (S6)
Each user stores their own login cookies (Netscape cookies.txt) for an
auth-walled download host (Facebook, Instagram, X, TikTok, Reddit) in
Settings; a download of an auth-walled link on that host is retried with
the acting user's cookie.

Two load-bearing security controls, both in downloads.credentials as the
single source of truth so enqueue and the worker can't drift:
- cache privacy: a cookie-authed download salts its MediaAsset format_sig
  with the user id, so the authed asset is private and never cache-served
  to another user. The worker attaches a cookie ONLY when the asset it is
  downloading into IS that private, salted identity.
- host scope (SEC-12): a cookie is resolved only for a URL whose netloc
  the credential owns (netloc-scoped _host_is); a look-alike/unrelated
  host gets none.

cookies_enc is Fernet-encrypted at rest, only decrypted in-worker into a
0600 file under staging/.auth/ (survives the retry wipe + _produced_file
scan) and unlinked in finally. The blob is never returned by a route,
logged, audited, or written to a job's error/snapshot. cookiefile is set
after the adapter's extra merge so an adapter can't clobber it. Settings
UI is write-only (host + set/updated only, never echoed). New
download_credentials table + migration 0074; per-user routes; HU+EN i18n.

Tests: host-scope, cache-privacy (no cross-user serve), encrypt-at-rest,
write-only API, worker attach-gate; FE dom test for the write-only field.
2026-08-28 03:53:04 +02:00

86 lines
3.5 KiB
Python

"""Download/edit child process — runs ONE job's heavy work (yt-dlp download or ffmpeg edit) in its
own process, launched and supervised by the worker (`app.worker._run_supervised`).
Why a separate process: a worker THREAD can't be killed, a C-level spin (a catastrophic regex, a
tight yt-dlp retry loop) can't even be cooperatively cancelled, and one such thread starves the
others via the GIL. Running the work in a child means the supervisor can SIGTERM/SIGKILL it (and its
process group, so ffmpeg grandchildren die too) on a stall / pause / wall-clock breach.
Contract: the asset is already claimed ('downloading') by the parent. This process does the work and
writes the terminal job/asset state itself (done / error, or a cooperative pause via the in-flight
progress hook), then exits 0. An unexpected crash exits non-zero and the parent fails the job.
"""
import logging
import os
import shutil
import subprocess
import sys
from app.config import settings
from app.db import SessionLocal
from app.downloads import edit as editmod
from app.models import DownloadJob
log = logging.getLogger("siftlode.worker.runner")
def _deprioritize() -> None:
"""Lower THIS child's CPU + IO priority so its yt-dlp/ffmpeg work — every descendant inherits the
handicap — can never starve the co-located API, Postgres, or Plex playback. Run once at startup,
before any heavy work. Every step is best-effort: a failed renice must never fail a download."""
nice_inc = settings.download_child_nice
if nice_inc > 0:
try:
os.nice(nice_inc) # relative increment; the child starts at the worker's nice (0)
except OSError as exc:
log.info("could not renice download child: %s", str(exc)[:120])
cls = settings.download_child_ionice_class
if cls > 0 and shutil.which("ionice"): # util-linux; absent on some minimal images
try:
subprocess.run(
["ionice", "-c", str(cls), "-p", str(os.getpid())],
capture_output=True,
timeout=5,
check=False,
)
except (OSError, subprocess.SubprocessError) as exc:
log.info("could not ionice download child: %s", str(exc)[:120])
# Cap OpenMP-parallel ffmpeg filters to the same budget as the encoder threads, so a filter
# graph can't fan out across every core behind ffmpeg's own `-threads` cap.
os.environ.setdefault("OMP_NUM_THREADS", str(editmod.encode_thread_cap()))
def main() -> None:
logging.basicConfig(level=logging.INFO)
_deprioritize()
if len(sys.argv) != 2:
print("usage: python -m app.downloads.runner <job_id>", file=sys.stderr)
raise SystemExit(2)
job_id = int(sys.argv[1])
with SessionLocal() as db:
job = db.get(DownloadJob, job_id)
if job is None:
return
asset_id = job.asset_id
job_kind = job.job_kind
spec = dict(job.profile_snapshot or {})
source_kind, source_ref = job.source_kind, job.source_ref
user_id = job.user_id
if asset_id is None:
return
# Imported here (not at module top) so the child pays the yt-dlp import cost only when it has
# real work, and to keep the import graph obvious: runner is a thin entry over the pipeline.
from app.downloads.pipeline import _download, _process_edit
if job_kind == "edit":
_process_edit(job_id, asset_id)
else:
_download(job_id, asset_id, source_kind, source_ref, spec, user_id)
if __name__ == "__main__":
main()