Files
siftlode/backend/app/downloads/runner.py
T
peter 54d19cc386 fix(logs): deep-review round 1 — say each failure once, and scrub it everywhere
- yt-dlp's text is scrubbed wherever it is logged, not only in the adapter:
  `formats.log_safe` takes out the URL, the `[extractor] <id>:` prefix and
  file paths, and the job-failed, refused, edit-failed and backfill lines use
  it. Done lines log the asset id, not the title-built path. The PII contract
  now bans `rel`/`rel_path`/`title`.
- A traceback goes with a download/edit failure only when it is our own code
  failing; for yt-dlp's DownloadError, our RuntimeErrors and OSErrors its foot
  is the unscrubbed message.
- yt-dlp's `error` maps to WARNING: it fires on attempts the fallback client
  set recovers from; the job's verdict is `download.job.failed`.
- The sink groups a bare `%s` pass-through by its text (numbers folded), and
  a process's last batch closes the repeat window, so a short-lived download
  child still reports what it dropped.
- Worker-side failures (stall, wall-clock, no asset, cached asset error) log
  `download.job.failed` with a cause; they left no line at all before. The
  crash, supervisor-error and non-zero-exit lines carry the code too.
- An edit failure is one coded line in `_fail_edit`, for every path.
- `logs.get_logger("__main__")` resolves to the `-m` module, so the worker
  and the download child keep their names.
- TRACE lines carrying user content are gated on `logs.consented_trace()`,
  not on the process level; a contract test pins it.
- The OAuth token refresh goes through `_upstream_failure`; transport errors
  carry reason `transport`. Subscribe recognises a duplicate by reason code
  only (the prose fallback was dead).
- Once-only guards for a stale sysconfig override and a refusing HLS session
  directory; item_detail splits Plex failures from our own parse bugs.
- The playlist breaker line names the playlist and the action; comments that
  were false (runner noqa, `_merge_vtt`, sink grouping) are corrected.
2026-09-18 03:16:15 +02:00

96 lines
4.1 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 os
import shutil
import subprocess
import sys
from app import logs
from app import logsink
from app.config import settings
from app.db import SessionLocal
from app.downloads import edit as editmod
from app.models import DownloadJob
log = logs.get_logger(__name__)
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:
logs.configure_logging("runner")
_deprioritize()
if len(sys.argv) != 2:
# noqa T201: a usage line is for the person who typed the command. Logging is already
# configured here, and in a deployment it writes JSON records — the one reader of this
# line wants the bare sentence, not a record with a request id they do not have.
print( # noqa: T201
"usage: python -m app.downloads.runner <job_id>", file=sys.stderr
)
raise SystemExit(2)
job_id = int(sys.argv[1])
# This whole process exists to run ONE job — tag every line it prints with it, so the child's
# output joins up with the worker's and the API's view of the same download.
logs.set_job(job_id)
logsink.start() # flushed at exit (atexit) — this process has no shutdown hook of its own
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()