36 lines
977 B
Python
36 lines
977 B
Python
from __future__ import annotations
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import os
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import fcntl
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from typing import Optional
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_LOCK_FD: Optional[int] = None # keep fd open for process lifetime
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def should_start_scheduler() -> bool:
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"""Return True in exactly one process (the scheduler owner).
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Under gunicorn --workers N, code is imported in N processes. If APScheduler
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starts at import time, you get N schedulers => N× API calls.
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We prevent that by taking a non-blocking exclusive lock on a lockfile.
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"""
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global _LOCK_FD
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if _LOCK_FD is not None:
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return True
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lock_path = os.environ.get("LAIR_SCHED_LOCK", "/tmp/lair-scheduler.lock")
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fd = os.open(lock_path, os.O_CREAT | os.O_RDWR, 0o644)
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try:
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fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
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_LOCK_FD = fd
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return True
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except BlockingIOError:
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os.close(fd)
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return False
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except Exception:
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try:
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os.close(fd)
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finally:
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return False
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