51 lines
1.9 KiB
Python
51 lines
1.9 KiB
Python
"""
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db_snapshot.py — WAL-safe snapshot / restore helpers for seismo_relay.db and
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the waveform store, backing the /db/snapshot, /db/waveforms/recent.zip and
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/db/restore endpoints in server.py. Kept out of server.py so the logic is
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unit-testable without HTTP.
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"""
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from __future__ import annotations
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import sqlite3
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import zipfile
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from pathlib import Path
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def snapshot_db(src_path: Path, dest_path: Path) -> Path:
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"""WAL-safe copy of a live SQLite DB via the SQLite online backup API.
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Consistent even while the source is being written under WAL, and never
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blocks the source's writers."""
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src = sqlite3.connect(str(src_path))
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dest = sqlite3.connect(str(dest_path))
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try:
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with dest:
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src.backup(dest)
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finally:
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src.close()
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dest.close()
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return Path(dest_path)
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def build_recent_waveforms_zip(db, store, n: int, dest_path: Path) -> dict:
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"""Zip every on-disk file (event file + .h5/.a5.pkl/.sfm.json siblings) for
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the n most-recent events, arcname '<serial>/<filename>'. Events with no
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resolvable files on disk are skipped. Returns {'events': int, 'files': int}."""
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rows = db.query_events(limit=n, offset=0)
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events = 0
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files = 0
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with zipfile.ZipFile(dest_path, "w", compression=zipfile.ZIP_DEFLATED) as zf:
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for row in rows:
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serial = row.get("serial")
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fn = row.get("blastware_filename")
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if not serial or not fn:
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continue
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serial_dir = store.root / serial
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matched = sorted(serial_dir.glob(f"{fn}*")) if serial_dir.is_dir() else []
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matched = [p for p in matched if p.is_file()]
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if not matched:
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continue
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events += 1
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for p in matched:
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zf.write(p, arcname=f"{serial}/{p.name}")
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files += 1
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return {"events": events, "files": files}
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