The SQLite DB is the signed append-only ledger, so a disk failure / stolen or
destroyed PC means total revenue-history loss (open-question #5). This is the first
slice of the backup-recovery design: the engine + a local/mounted target + a daily
timer + a manual route.
Engine (apps/server/src/backup.ts):
- Consistent online copy of the live WAL DB via better-sqlite3's native .backup()
(not a raw file copy, which can capture a torn WAL) — the restored copy is a
byte-identical, queryable DB.
- AES-256-GCM with a scrypt-derived key from BACKUP_KEY; self-describing header
(magic|version|salt|iv|...|authTag) so a restore tool needs only the key + file.
Zero new dependencies (Node crypto).
- The plaintext intermediate is kept in scratch (not the removable/network target)
and wiped in a finally, success or fail.
- Retention: keep-last-N + one-per-day within N days.
Wiring:
- BackupService (env config, single in-flight guard, last-success/last-error).
- routes/backup.ts: GET /api/backup/status (backup:read), POST /api/backup/run
(backup:create), 409 when unconfigured. No restore route — restore is an
out-of-band runbook action on a fresh appliance, not a console call.
- New permission resource in @parking/shared.
- server.ts: an unref'd daily timer, a no-op until BACKUP_TARGET_DIR + BACKUP_KEY
are set, deliberately not run at startup (a just-power-cut booth shouldn't write
to a possibly-unmounted disk).
- openRawDb() added to @parking/db/testing (open a file without migrating, for
restore-verification tests).
BACKUP_KEY is deliberately SEPARATE from EVENT_SIGNING_KEY (independent rotation;
backups travel, the signing key shouldn't). SMB/NFS work as mount paths; SFTP +
admin UI + restore runbook are deferred slices. Tests: round-trip byte-identical,
GCM tamper/wrong-key fail, short-key rejected, scratch cleaned, route auth/RBAC +
409. build/lint/test green (212 server tests). Wiki + open-question #5 updated.
Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V
New concept page backup-recovery.md resolving the design half of open-question #5.
Driving scenario: a stolen/destroyed PC whose LUKS+TPM disk is unrecoverable by
design — recovery stands up a NEW PC, restores a backup, and keeps signing the
SAME chain.
Settled: admin-driven encrypted full-DB backup (SQLite online-backup/VACUUM INTO,
snapshots included) to local/USB, SMB/NFS, or SFTP targets; manual button + an
in-process daily timer; keep-last-N + dailies retention; restore is admin-only /
out-of-band (operator-adversary surface). A restored copy must still verifyChain.
Key custody (the load-bearing decision, bears on #6): three independent keys —
EVENT_SIGNING_KEY kept an extractable, escrowed software key DECOUPLED from the
TPM so the ledger survives total hardware loss (the conscious trade: a TPM-sealed
signing key would be unforgeable but permanently unverifiable after the machine
dies); a NEW dedicated park_buzi_backup_key in Komodo for backup encryption,
separate from the signing key; the LUKS/TPM disk key, appliance-only and
deliberately non-recoverable. Keys are never inside the backup they unlock.
Updated open-questions #5 (design SETTLED) + #10 note; disk-os-hardening deploy
runbook (why the signing key is not sealed + park_buzi_backup_key); index catalog
+ concept count. Design only — not yet built.
Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V
julian