42 lines
1.2 KiB
Python
42 lines
1.2 KiB
Python
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"""Shared utility functions for hermes-agent."""
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import json
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import os
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import tempfile
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from pathlib import Path
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from typing import Any, Union
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def atomic_json_write(path: Union[str, Path], data: Any, *, indent: int = 2) -> None:
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"""Write JSON data to a file atomically.
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Uses temp file + fsync + os.replace to ensure the target file is never
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left in a partially-written state. If the process crashes mid-write,
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the previous version of the file remains intact.
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Args:
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path: Target file path (will be created or overwritten).
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data: JSON-serializable data to write.
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indent: JSON indentation (default 2).
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"""
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path = Path(path)
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path.parent.mkdir(parents=True, exist_ok=True)
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fd, tmp_path = tempfile.mkstemp(
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dir=str(path.parent),
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prefix=f".{path.stem}_",
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suffix=".tmp",
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)
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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(data, f, indent=indent, ensure_ascii=False)
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f.flush()
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os.fsync(f.fileno())
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os.replace(tmp_path, path)
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except BaseException:
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try:
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os.unlink(tmp_path)
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except OSError:
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pass
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raise
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