Files
hermes-agent/utils.py
teknium1 d63b363cde refactor: extract atomic_json_write helper, add 24 checkpoint tests
Extract the duplicated temp-file + fsync + os.replace pattern from
batch_runner.py (1 instance) and process_registry.py (2 instances) into
a shared utils.atomic_json_write() function.

Add 12 tests for atomic_json_write covering: valid JSON, parent dir
creation, overwrite, crash safety (original preserved on error), no temp
file leaks, string paths, unicode, custom indent, concurrent writes.

Add 12 tests for batch_runner checkpoint behavior covering:
_save_checkpoint (valid JSON, last_updated, overwrite, lock/no-lock,
parent dirs, no temp leaks), _load_checkpoint (missing file, existing
data, corrupt JSON), and resume logic (preserves prior progress,
different run_name starts fresh).
2026-03-06 05:50:12 -08:00

42 lines
1.2 KiB
Python

"""Shared utility functions for hermes-agent."""
import json
import os
import tempfile
from pathlib import Path
from typing import Any, Union
def atomic_json_write(path: Union[str, Path], data: Any, *, indent: int = 2) -> None:
"""Write JSON data to a file atomically.
Uses temp file + fsync + os.replace to ensure the target file is never
left in a partially-written state. If the process crashes mid-write,
the previous version of the file remains intact.
Args:
path: Target file path (will be created or overwritten).
data: JSON-serializable data to write.
indent: JSON indentation (default 2).
"""
path = Path(path)
path.parent.mkdir(parents=True, exist_ok=True)
fd, tmp_path = tempfile.mkstemp(
dir=str(path.parent),
prefix=f".{path.stem}_",
suffix=".tmp",
)
try:
with os.fdopen(fd, "w", encoding="utf-8") as f:
json.dump(data, f, indent=indent, ensure_ascii=False)
f.flush()
os.fsync(f.fileno())
os.replace(tmp_path, path)
except BaseException:
try:
os.unlink(tmp_path)
except OSError:
pass
raise