54 lines
1.5 KiB
Python
54 lines
1.5 KiB
Python
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from __future__ import annotations
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import json
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import os
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import tempfile
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from typing import Any, Optional, Tuple
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def cache_dir() -> str:
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"""Directory where the scheduler owner writes shared cache JSON files."""
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d = os.environ.get("LAIR_CACHE_DIR", "/tmp/lair-cache")
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os.makedirs(d, exist_ok=True)
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return d
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def cache_file(name: str) -> str:
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return os.path.join(cache_dir(), f"{name}.json")
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def atomic_write_json(path: str, payload: dict) -> None:
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"""Write JSON atomically so readers never observe partial content."""
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parent = os.path.dirname(path) or "."
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fd, tmp = tempfile.mkstemp(prefix=".tmp-", dir=parent)
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try:
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with os.fdopen(fd, "w", encoding="utf-8") as f:
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json.dump(payload, f, ensure_ascii=False, separators=(",", ":"))
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os.replace(tmp, path)
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finally:
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try:
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if os.path.exists(tmp):
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os.unlink(tmp)
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except Exception:
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pass
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def load_json_if_newer(path: str, last_mtime: float) -> Tuple[Optional[dict], float]:
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"""Load JSON only if the file exists and has mtime newer than last_mtime."""
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try:
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st = os.stat(path)
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except FileNotFoundError:
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return None, last_mtime
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except Exception:
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return None, last_mtime
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mtime = float(st.st_mtime)
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if mtime <= float(last_mtime):
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return None, last_mtime
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try:
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with open(path, "r", encoding="utf-8") as f:
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return json.load(f), mtime
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except Exception:
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return None, last_mtime
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