Oleksandr Kozachuk
81 lines
2.4 KiB
Python
81 lines
2.4 KiB
Python
#!/usr/bin/env python3
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"""Consistent, rotated bot.db backups (SPEC-012 OPS-13).
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Run from cron on each host. Uses the sqlite3 online-backup API so the
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snapshot is consistent even while the bot writes (WAL-safe), gzips it,
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and keeps the newest N. Stdlib only.
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Usage: python3 backup_db.py <bot.db> <backup-dir> [keep]
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"""
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import gzip
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import os
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import shutil
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import sqlite3
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import sys
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import tempfile
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import time
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from pathlib import Path
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DEFAULT_KEEP = 14
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BACKUP_GLOB = "bot-*.db.gz"
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def snapshot(src: Path, dest_gz: Path) -> None:
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"""Write a consistent gzipped snapshot of src to dest_gz (OPS-13)."""
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fd, tmp_path = tempfile.mkstemp(suffix=".db", dir=str(dest_gz.parent))
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os.close(fd)
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tmp = Path(tmp_path)
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try:
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source = sqlite3.connect(str(src))
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try:
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target = sqlite3.connect(str(tmp))
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try:
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source.backup(target) # atomic, WAL-safe online backup
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finally:
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target.close()
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finally:
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source.close()
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with open(tmp, "rb") as raw, gzip.open(str(dest_gz), "wb") as gz:
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shutil.copyfileobj(raw, gz)
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os.chmod(dest_gz, 0o600) # conversation data
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finally:
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tmp.unlink(missing_ok=True)
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def victims(existing: list, keep: int) -> list:
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"""Given backup paths (any order), return the ones to delete, oldest first (OPS-14)."""
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ordered = sorted(existing) # timestamped names sort chronologically
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return ordered[: max(0, len(ordered) - keep)]
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def rotate(backup_dir: Path, keep: int) -> int:
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removed = 0
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for path in victims(list(backup_dir.glob(BACKUP_GLOB)), keep):
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Path(path).unlink(missing_ok=True)
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removed += 1
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return removed
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def main() -> int:
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if len(sys.argv) < 3:
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print("usage: backup_db.py <bot.db> <backup-dir> [keep]", file=sys.stderr)
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return 2
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src = Path(sys.argv[1]).expanduser()
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backup_dir = Path(sys.argv[2]).expanduser()
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keep = int(sys.argv[3]) if len(sys.argv) > 3 else DEFAULT_KEEP
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if not src.exists():
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print(f"backup: source {src} missing", file=sys.stderr)
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return 1
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backup_dir.mkdir(parents=True, exist_ok=True)
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stamp = time.strftime("%Y%m%d-%H%M%S", time.gmtime())
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dest = backup_dir / f"bot-{stamp}.db.gz"
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snapshot(src, dest)
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removed = rotate(backup_dir, keep)
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print(f"backup: wrote {dest.name} ({dest.stat().st_size} bytes), rotated {removed} old")
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return 0
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if __name__ == "__main__":
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sys.exit(main())
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