digital-garbage
478fb835dd
Stop only reaches jobs that check for it; a failure landing with Stop counts as a stop. Hint for imported workflows corrected.
72 lines
2.7 KiB
Python
72 lines
2.7 KiB
Python
"""Background jobs (final render, combined export): ffmpeg can outlast a tunnel's request
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timeout, so the request returns an id and the page polls for it."""
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import asyncio
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import uuid
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from collections import OrderedDict
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MAX_JOBS = 50 # finished jobs are kept this long for the poll that reads them
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_jobs: "OrderedDict[str, dict]" = OrderedDict()
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_stop: set = set() # ids asked to stop; the job notices between chunks
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_can_stop: set = set() # ids whose work checks for it
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class Stopped(Exception):
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"""Raised inside a job that was asked to stop; its partial output is removed by whoever was writing it."""
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def stop(job: str) -> bool:
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"""Ask a queued or running job to stop. False when there is no such job or it already ended."""
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entry = _jobs.get(job)
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if job not in _can_stop or not entry or entry.get("state") not in ("queued", "running"):
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return False
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_stop.add(job)
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return True
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def check(job: str) -> None:
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"""Raises Stopped once `stop(job)` was called: the hook a long job calls between its chunks."""
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if job in _stop:
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raise Stopped()
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def new(stoppable: bool = False) -> str:
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"""`stoppable`: the work calls its `interrupted()` hook, so a stop request will end it."""
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job = uuid.uuid4().hex
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_jobs[job] = {"state": "queued"}
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if stoppable:
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_can_stop.add(job)
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for old in [k for k, v in _jobs.items() if v.get("state") in ("done", "error", "stopped")]:
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if len(_jobs) <= MAX_JOBS:
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break
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del _jobs[old] # only finished ones: a running job's poll must keep finding it
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return job
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def get(job: str) -> dict | None:
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return _jobs.get(job)
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async def run(job: str, fn, *args, error, stoppable: bool = False) -> None:
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"""Run the blocking `fn(*args)` off the event loop and record how it ended. `error` is the
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exception class whose message is meant for the person; anything else is reported plainly."""
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if job in _stop: # stopped while it was still queued
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_stop.discard(job)
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_can_stop.discard(job)
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_jobs[job] = {"state": "stopped"}
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return
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_jobs[job] = {"state": "running"}
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try:
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result = await asyncio.to_thread(fn, *args, **({"interrupted": lambda: check(job)} if stoppable else {}))
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_jobs[job] = {"state": "done", **result}
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except Stopped:
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_jobs[job] = {"state": "stopped"}
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except error as exc:
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_jobs[job] = {"state": "error", "detail": str(exc)}
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except Exception as exc: # noqa: BLE001
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_jobs[job] = {"state": "error", "detail": f"{type(exc).__name__}: {exc}"}
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finally:
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_stop.discard(job)
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_can_stop.discard(job)
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