Lukas
5d24780c63
- Create logged_task() helper in backend/app/utils/async_utils.py to wrap fire-and-forget coroutines with exception logging - Ensures unhandled task exceptions are always logged to structlog instead of silently discarded (Python 3.11+ RuntimeWarning) - Update ban_service.py to use logged_task() for geo_cache.lookup_batch() background resolution - Add comprehensive tests for logged_task() in test_async_utils.py - Document fire-and-forget task conventions in Backend-Development.md The logged_task() wrapper catches any exception raised in a background task, logs it with full traceback context and task name, and never re-raises. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
75 lines
2.0 KiB
Python
75 lines
2.0 KiB
Python
"""Async execution utilities.
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Provides a shared thread-backed executor abstraction and helpers for
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running blocking callables without stalling the FastAPI event loop.
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"""
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from __future__ import annotations
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import asyncio
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import functools
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from collections.abc import Callable, Coroutine
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from concurrent.futures import ThreadPoolExecutor
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from typing import Any, ParamSpec, TypeVar
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import structlog
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P = ParamSpec("P")
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T = TypeVar("T")
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log: structlog.stdlib.BoundLogger = structlog.get_logger()
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DEFAULT_BLOCKING_EXECUTOR: ThreadPoolExecutor = ThreadPoolExecutor(
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max_workers=16,
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thread_name_prefix="bangui-blocking",
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)
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async def run_blocking(
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func: Callable[P, T],
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*args: P.args,
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executor: ThreadPoolExecutor | None = None,
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**kwargs: P.kwargs,
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) -> T:
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"""Run a blocking callable in the shared thread pool.
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Args:
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func: Blocking callable to execute.
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*args: Positional arguments for the callable.
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executor: Optional custom executor. Defaults to the shared pool.
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**kwargs: Keyword arguments for the callable.
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Returns:
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The callable return value.
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"""
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loop = asyncio.get_running_loop()
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executor = DEFAULT_BLOCKING_EXECUTOR if executor is None else executor
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if kwargs:
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func = functools.partial(func, *args, **kwargs)
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return await loop.run_in_executor(executor, func)
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return await loop.run_in_executor(executor, func, *args)
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async def logged_task(
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coro: Coroutine[Any, Any, Any],
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name: str,
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) -> None:
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"""Execute a coroutine with automatic exception logging.
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Wraps fire-and-forget tasks to ensure exceptions are always logged and
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do not become unhandled task exceptions. Use with asyncio.create_task():
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asyncio.create_task(
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logged_task(some_coroutine(), "task_name"),
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name="task_name"
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)
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Args:
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coro: Coroutine to execute.
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name: Task name for logging context.
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"""
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try:
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await coro
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except Exception: # noqa: BLE001
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log.exception("background_task_failed", task_name=name)
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