83 lines
2.7 KiB
Python
83 lines
2.7 KiB
Python
# ============================================================
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# 审计 append-only 文件锁辅助 v1（moduleId: core-audit-filelock, 可重生 ✅）
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# plan.md §3.6 / 矩阵「审计 append-only」剩余项：跨进程锁强化
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# JSONL 追加写使用跨进程独占锁（Windows msvcrt；其他平台退化为进程内锁），
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# 防止多进程/多线程并发 append 行交错导致审计证据损坏；失败重试可配。
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# ============================================================
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from __future__ import annotations
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import os
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import threading
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import time
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from contextlib import contextmanager
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from pathlib import Path
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from typing import Any
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# 锁重试（秒）：拿不到锁时轮询等待，避免瞬时竞争直接失败
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_LOCK_RETRY_SECONDS = float(os.environ.get("APS_AUDIT_LOCK_RETRY_SECONDS") or "10.0")
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_LOCK_STEP = 0.02
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try: # Windows：msvcrt 文件区域锁
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import msvcrt
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_HAS_MSVCRT = True
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except ImportError: # 其他平台：仅进程内锁
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_HAS_MSVCRT = False
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_lock_registry: dict[str, threading.Lock] = {}
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_lock_registry_guard = threading.Lock()
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def _process_lock_for(path: Path) -> threading.Lock:
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key = str(path)
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with _lock_registry_guard:
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lock = _lock_registry.get(key)
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if lock is None:
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lock = threading.Lock()
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_lock_registry[key] = lock
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return lock
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@contextmanager
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def locked_append(path: Path) -> Any:
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"""跨进程安全的 JSONL 追加写上下文。
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先取进程内锁（串行化同进程线程），再取跨进程文件锁（msvcrt 区域锁），
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最后以追加模式打开文件并 yield file handle；退出时 flush+fsync。
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"""
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proc = _process_lock_for(path)
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with proc:
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path.parent.mkdir(parents=True, exist_ok=True)
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with open(path, "a", encoding="utf-8") as fh:
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if _HAS_MSVCRT:
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_acquire_msvcrt(fh)
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try:
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yield fh
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finally:
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_release_msvcrt(fh)
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else:
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yield fh
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fh.flush()
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os.fsync(fh.fileno())
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def _acquire_msvcrt(fh: Any) -> None:
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"""对文件首字节区域加独占锁（重试至超时）。"""
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deadline = time.monotonic() + _LOCK_RETRY_SECONDS
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while True:
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try:
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fh.seek(0)
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msvcrt.locking(fh.fileno(), msvcrt.LK_LOCK, 1)
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return
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except OSError:
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if time.monotonic() >= deadline:
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raise
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time.sleep(_LOCK_STEP)
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def _release_msvcrt(fh: Any) -> None:
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try:
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fh.seek(0)
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msvcrt.locking(fh.fileno(), msvcrt.LK_UNLCK, 1)
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except OSError:
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pass
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