Six durability experiments of 3 October 2026: results, raw output, the two prototypes, the runner
f8975ed verified | #!/usr/bin/env python3 | |
| """sqlite-stage: a consistent copy of live SQLite databases, for the backup to take. | |
| sqlite-stage.py DEST_DIR DATABASE [DATABASE ...] | |
| A backup that copies a database file while a service writes to it can catch the file and its write-ahead log | |
| at different moments, and the copy may not open. SQLite's own backup API reads a consistent snapshot while | |
| the writer keeps writing. Each database lands in DEST_DIR under its path with slashes as underscores, written | |
| to a temporary name, checked (`quick_check`), synced and renamed: a half copy never has the final name. | |
| A missing database is skipped; a failed one is reported and makes the exit status 1, and the others still run. | |
| """ | |
| from __future__ import annotations | |
| import os | |
| import sqlite3 | |
| import sys | |
| from pathlib import Path | |
| def stage(source: Path, dest_dir: Path) -> str: | |
| name = str(source).replace(str(Path.home()), "").strip("/").replace("/", "_") | |
| final = dest_dir / name | |
| tmp = dest_dir / (name + ".tmp") | |
| tmp.unlink(missing_ok=True) | |
| try: | |
| src = sqlite3.connect(f"file:{source}?mode=ro", uri=True, timeout=30) | |
| dst = sqlite3.connect(tmp) | |
| try: | |
| src.backup(dst) | |
| ok = dst.execute("PRAGMA quick_check").fetchone()[0] | |
| finally: | |
| dst.close() | |
| src.close() | |
| if ok != "ok": | |
| raise sqlite3.DatabaseError(f"the copy does not pass quick_check: {ok}") | |
| except sqlite3.Error: | |
| tmp.unlink(missing_ok=True) # a half copy never stays, under any name | |
| raise | |
| with open(tmp, "rb") as fh: | |
| os.fsync(fh.fileno()) | |
| os.replace(tmp, final) | |
| return f"{source} -> {final} ({final.stat().st_size} bytes)" | |
| def main(argv: list[str]) -> int: | |
| if len(argv) < 2: | |
| print(__doc__.strip().splitlines()[2].strip(), file=sys.stderr) | |
| return 2 | |
| dest = Path(argv[0]) | |
| dest.mkdir(parents=True, exist_ok=True) | |
| failed = 0 | |
| for arg in argv[1:]: | |
| source = Path(arg) | |
| if not source.exists(): | |
| continue | |
| try: | |
| print(stage(source, dest)) | |
| except sqlite3.Error as e: | |
| failed = 1 | |
| print(f"sqlite-stage: {source}: {e}", file=sys.stderr) | |
| fd = os.open(dest, os.O_RDONLY) | |
| os.fsync(fd) | |
| os.close(fd) | |
| return failed | |
| if __name__ == "__main__": | |
| raise SystemExit(main(sys.argv[1:])) | |