hermes-agent/agent/async_utils.py
kshitijk4poor c78aa0bad5 refactor(gateway): dedupe detached-task consumer + reconnect backoff policy
/simplify-code findings on the #66222 salvage:

- consume_detached_task_result moves to agent/async_utils.py (shared home);
  gateway/run.py and the Discord adapter both had near-identical copies of
  the same pattern (a third lives in the telegram adapter). One canonical
  implementation, both new callsites import it.
- Reconnect backoff formula min(30 * 2^(n-1), 300) was copied verbatim at
  3 sites in run.py (primary watcher x2, secondary-profile reconnect), the
  third hardcoding the cap. Hoisted to module-level _reconnect_backoff()
  with a single _RECONNECT_BACKOFF_CAP so a future tune can't silently
  miss one path.

Behavior-preserving: 70 gateway teardown/liveness/reconnect tests green.
2026-07-18 20:01:55 +05:30

84 lines
3.1 KiB
Python

"""Async/sync bridging helpers.
The codebase has ~30 sites that schedule a coroutine onto an event loop from a
worker thread via :func:`asyncio.run_coroutine_threadsafe`. That function can
raise :class:`RuntimeError` (e.g. the loop was closed during a shutdown race),
and when it does the coroutine object is never awaited and never closed —
which triggers a ``"coroutine '<name>' was never awaited"`` RuntimeWarning and
leaks the coroutine's frame until GC.
:func:`safe_schedule_threadsafe` wraps the call, closes the coroutine on
scheduling failure, and returns ``None`` (instead of a half-formed future) so
callers can branch cleanly:
fut = safe_schedule_threadsafe(coro, loop)
if fut is None:
return # or fallback behavior
fut.result(timeout=5)
The helper deliberately does NOT also handle ``future.result()`` failures —
that is a separate concern. Once the loop has accepted the coroutine, its
lifecycle belongs to the loop, not the scheduling thread.
"""
from __future__ import annotations
import asyncio
import logging
from concurrent.futures import Future
from typing import Any, Coroutine, Optional
_DEFAULT_LOGGER = logging.getLogger(__name__)
def safe_schedule_threadsafe(
coro: Coroutine[Any, Any, Any],
loop: Optional[asyncio.AbstractEventLoop],
*,
logger: Optional[logging.Logger] = None,
log_message: str = "Failed to schedule coroutine on loop",
log_level: int = logging.DEBUG,
) -> Optional[Future]:
"""Schedule ``coro`` on ``loop`` from a sync context, leak-safe.
Returns the :class:`concurrent.futures.Future` on success, or ``None`` if
the loop is missing or :func:`asyncio.run_coroutine_threadsafe` raised
(e.g. the loop was closed during a shutdown race). In all failure paths
the coroutine is :meth:`close`-d so it does not trigger
``"coroutine was never awaited"`` warnings or leak its frame.
Callers retain full control over what to do with the returned future
(call ``.result(timeout=...)``, attach ``add_done_callback``, ignore it
fire-and-forget, etc.).
"""
log = logger if logger is not None else _DEFAULT_LOGGER
if loop is None:
if asyncio.iscoroutine(coro):
coro.close()
log.log(log_level, "%s: loop is None", log_message)
return None
try:
return asyncio.run_coroutine_threadsafe(coro, loop)
except Exception as exc:
if asyncio.iscoroutine(coro):
coro.close()
log.log(log_level, "%s: %s", log_message, exc)
return None
def consume_detached_task_result(task: "asyncio.Future[Any]") -> None:
"""Retrieve a detached task's result without surfacing cancellation.
Used as an ``add_done_callback`` on tasks that were cancelled and
detached (e.g. an adapter close path that swallows ``CancelledError``
past its teardown deadline). Observing ``task.exception()`` prevents
"exception was never retrieved" noise on the event loop; cancellation
and any terminal error are deliberately swallowed — the task's owner
already gave up on it.
"""
try:
task.exception()
except (asyncio.CancelledError, Exception):
pass