41 lines
1.4 KiB
Python
41 lines
1.4 KiB
Python
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"""Lightweight, decoupled progress reporting for long-running scheduler jobs.
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A job's work function calls `report(current, total, phase)`; the scheduler binds a sink (via
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`bind()`) that forwards it into the in-memory activity the admin dashboard polls. A contextvar
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holds the sink, so the sync code stays unaware of the scheduler and concurrent jobs (each in
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its own thread/context) never cross wires. When no sink is bound (e.g. a manual sync endpoint),
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`report` is a cheap no-op.
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"""
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import contextvars
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from typing import Callable, Optional
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Sink = Callable[[int, Optional[int], Optional[str]], None]
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_sink: contextvars.ContextVar[Optional[Sink]] = contextvars.ContextVar(
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"progress_sink", default=None
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)
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def report(current: int, total: int | None = None, phase: str | None = None) -> None:
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"""Report job progress to the bound sink, if any. `total=None` means indeterminate."""
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sink = _sink.get()
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if sink is not None:
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sink(current, total, phase)
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class bind:
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"""Context manager that binds a progress sink for the duration of a job run."""
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def __init__(self, sink: Sink):
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self._sink = sink
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self._token = None
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def __enter__(self) -> "bind":
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self._token = _sink.set(self._sink)
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return self
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def __exit__(self, *exc) -> bool:
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if self._token is not None:
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_sink.reset(self._token)
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return False
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