Files
siftlode/backend/app/downloads/runner.py
T
peter 0cff964ff2 refactor(logs): name every logger after its module, and hold it there
25 literal names covered 34 modules. plex/client.py, plex/stream.py,
plex/subtitles.py, plex/sync.py and two Plex route modules all called themselves
`siftlode.plex`; downloads/pipeline.py called itself `siftlode.worker`;
routes/channels.py called itself `siftlode.api`. The `logger` column is in every
stored row so E22.6's console can filter on it, and so an operator can pin a level
to one part of the system — neither works when six modules share a name.

`logs.get_logger(__name__)` derives it: app/plex/sync.py -> siftlode.plex.sync.
One name per module, and it cannot drift from the file it sits in.
tests/test_logger_names.py pins the derivation, that everything stays under the
one `siftlode` tree the handler and the tests attach to, and that no module
hand-rolls a name again unless the line says why (`# logger-name-ok: <why>`).
Two do: get_logger's own call, and `siftlode.http`, which is named for the traffic
it carries rather than the module it lives in — it replaced uvicorn's access log
and is what an operator pins when they want request lines and nothing else.

app/scheduler.py called its logger `logger`; every other module calls it `log`.

ruff gains LOG, G, T20, TRY400, TRY401 and S112. Four findings cleared with them:
worker.py logged `str(exc)[:120]` where the traceback was the whole question, and
three prints/f-strings that are deliberate now say so on the line. S110 and BLE001
stay off until S3 — 23 handlers are outstanding and each is a judgement about one
of them; enabling the rules first would just mean 23 blanket noqas.
2026-09-18 00:57:57 +02:00

95 lines
4.0 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: this runs BEFORE configure_logging, and a usage error has to reach the
# operator who typed it whether or not logging was ever set up.
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()