Lukas
05c3b564ae
- Add heartbeat-based lock renewal in scheduler_lock_heartbeat.py - Update scheduler_lock.py with improved lock management - Add comprehensive tests for scheduler lock functionality - Update deployment and task documentation Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
112 lines
3.8 KiB
Python
112 lines
3.8 KiB
Python
"""Scheduler lock heartbeat background task.
|
|
|
|
Registers an APScheduler job that periodically updates the scheduler lock's
|
|
heartbeat timestamp. This prevents the lock from being considered stale
|
|
if the running instance experiences temporary delays or high load.
|
|
|
|
Without this heartbeat, stale lock detection (based on TTL) could incorrectly
|
|
determine that the scheduler instance has crashed when it's merely busy, and
|
|
a new instance could take over.
|
|
"""
|
|
|
|
from __future__ import annotations
|
|
|
|
from typing import TYPE_CHECKING
|
|
|
|
import structlog
|
|
|
|
from app.tasks.db import task_db
|
|
from app.tasks.timeout_utils import run_with_timeout
|
|
from app.utils.runtime_state import get_effective_settings
|
|
from app.utils.scheduler_lock import update_scheduler_lock_heartbeat
|
|
|
|
if TYPE_CHECKING:
|
|
from fastapi import FastAPI
|
|
|
|
from app.config import Settings
|
|
|
|
log: structlog.stdlib.BoundLogger = structlog.get_logger()
|
|
|
|
#: How often the heartbeat job fires (seconds). Must be significantly less than
|
|
#: the lock TTL to allow multiple missed heartbeats before lock expiry.
|
|
SCHEDULER_LOCK_HEARTBEAT_INTERVAL: int = 5
|
|
|
|
#: Stable APScheduler job ID — ensures re-registration replaces, not duplicates.
|
|
JOB_ID: str = "scheduler_lock_heartbeat"
|
|
|
|
#: Maximum seconds to allow for scheduler lock heartbeat to complete.
|
|
TASK_TIMEOUT_SECONDS: int = 5
|
|
|
|
|
|
async def _update_heartbeat_with_resources(settings: Settings) -> None:
|
|
"""Update the scheduler lock heartbeat timestamp.
|
|
|
|
If the heartbeat update fails (e.g., we no longer hold the lock), log
|
|
a warning but don't crash the scheduler. This allows the running
|
|
application to continue even if something went wrong.
|
|
|
|
The heartbeat must complete within TASK_TIMEOUT_SECONDS to prevent
|
|
scheduler starvation. If it exceeds this timeout, a warning is logged
|
|
and the task is cancelled.
|
|
|
|
Args:
|
|
settings: The resolved application settings used for database access.
|
|
"""
|
|
|
|
async def _do_update() -> None:
|
|
async with task_db(settings) as db:
|
|
success = await update_scheduler_lock_heartbeat(db)
|
|
|
|
if success:
|
|
log.debug("scheduler_lock_heartbeat_updated")
|
|
else:
|
|
log.warning(
|
|
"scheduler_lock_heartbeat_failed",
|
|
message="Failed to update heartbeat; we no longer hold the lock. "
|
|
"Another instance may have taken over or the database connection failed.",
|
|
)
|
|
|
|
try:
|
|
await run_with_timeout("scheduler_lock_heartbeat", _do_update(), TASK_TIMEOUT_SECONDS)
|
|
except TimeoutError:
|
|
log.error(
|
|
"scheduler_lock_heartbeat_timeout",
|
|
timeout_seconds=TASK_TIMEOUT_SECONDS,
|
|
message="Heartbeat update exceeded timeout. The database may be slow or unresponsive.",
|
|
)
|
|
except Exception as e:
|
|
log.error(
|
|
"scheduler_lock_heartbeat_error",
|
|
error=str(e),
|
|
message="Unexpected error during heartbeat update.",
|
|
)
|
|
|
|
|
|
async def _update_heartbeat(app: FastAPI) -> None:
|
|
await _update_heartbeat_with_resources(get_effective_settings(app))
|
|
|
|
|
|
def register(app: FastAPI) -> None:
|
|
"""Add (or replace) the scheduler lock heartbeat job.
|
|
|
|
Must be called after the scheduler has been started (i.e., inside the
|
|
lifespan handler, after ``scheduler.start()``).
|
|
|
|
Args:
|
|
app: The :class:`fastapi.FastAPI` application instance whose
|
|
``app.state.scheduler`` will receive the job.
|
|
"""
|
|
settings = get_effective_settings(app)
|
|
app.state.scheduler.add_job(
|
|
_update_heartbeat_with_resources,
|
|
trigger="interval",
|
|
seconds=SCHEDULER_LOCK_HEARTBEAT_INTERVAL,
|
|
kwargs={"settings": settings},
|
|
id=JOB_ID,
|
|
replace_existing=True,
|
|
)
|
|
log.info(
|
|
"scheduler_lock_heartbeat_scheduled",
|
|
interval_seconds=SCHEDULER_LOCK_HEARTBEAT_INTERVAL,
|
|
)
|