69 lines
2.5 KiB
Python
69 lines
2.5 KiB
Python
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"""Async/sync bridging helpers.
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The codebase has ~30 sites that schedule a coroutine onto an event loop from a
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worker thread via :func:`asyncio.run_coroutine_threadsafe`. That function can
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raise :class:`RuntimeError` (e.g. the loop was closed during a shutdown race),
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and when it does the coroutine object is never awaited and never closed —
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which triggers a ``"coroutine '<name>' was never awaited"`` RuntimeWarning and
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leaks the coroutine's frame until GC.
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:func:`safe_schedule_threadsafe` wraps the call, closes the coroutine on
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scheduling failure, and returns ``None`` (instead of a half-formed future) so
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callers can branch cleanly:
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fut = safe_schedule_threadsafe(coro, loop)
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if fut is None:
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return # or fallback behavior
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fut.result(timeout=5)
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The helper deliberately does NOT also handle ``future.result()`` failures —
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that is a separate concern. Once the loop has accepted the coroutine, its
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lifecycle belongs to the loop, not the scheduling thread.
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"""
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from __future__ import annotations
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import asyncio
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import logging
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from concurrent.futures import Future
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from typing import Any, Coroutine, Optional
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_DEFAULT_LOGGER = logging.getLogger(__name__)
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def safe_schedule_threadsafe(
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coro: Coroutine[Any, Any, Any],
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loop: Optional[asyncio.AbstractEventLoop],
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*,
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logger: Optional[logging.Logger] = None,
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log_message: str = "Failed to schedule coroutine on loop",
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log_level: int = logging.DEBUG,
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) -> Optional[Future]:
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"""Schedule ``coro`` on ``loop`` from a sync context, leak-safe.
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Returns the :class:`concurrent.futures.Future` on success, or ``None`` if
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the loop is missing or :func:`asyncio.run_coroutine_threadsafe` raised
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(e.g. the loop was closed during a shutdown race). In all failure paths
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the coroutine is :meth:`close`-d so it does not trigger
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``"coroutine was never awaited"`` warnings or leak its frame.
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Callers retain full control over what to do with the returned future
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(call ``.result(timeout=...)``, attach ``add_done_callback``, ignore it
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fire-and-forget, etc.).
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"""
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log = logger if logger is not None else _DEFAULT_LOGGER
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if loop is None:
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if asyncio.iscoroutine(coro):
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coro.close()
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log.log(log_level, "%s: loop is None", log_message)
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return None
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try:
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return asyncio.run_coroutine_threadsafe(coro, loop)
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except Exception as exc:
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if asyncio.iscoroutine(coro):
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coro.close()
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log.log(log_level, "%s: %s", log_message, exc)
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return None
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