fix(localdb): fault live sync session on cap-prune; keepalive + newest-wins sync guard (0.3.2, ScadaBridge arch-review P4-1 + P4-3)

This commit is contained in:
Joseph Doherty
2026-08-19 14:49:31 -04:00
parent dbcbc5bd41
commit f62b017cc7
13 changed files with 574 additions and 21 deletions
+26 -1
View File
@@ -10,7 +10,7 @@ Change capture uses SQLite triggers writing a single HLC-stamped oplog inside th
consumer's own write transaction (crash-consistent, non-bypassable). Convergence is
last-writer-wins over a hybrid logical clock. All timestamps are UTC.
## Packages (all `0.3.0`)
## Packages (all `0.3.2`)
| Package | Contents |
|---|---|
@@ -20,6 +20,31 @@ last-writer-wins over a hybrid logical clock. All timestamps are UTC.
> Status: **published to the Gitea feed; adopted by ScadaBridge (Phases 1+2) and OtOpcUa (Phase 1).**
>
> - `0.3.2` (2026-08-19) — two Medium findings from the ScadaBridge adversarial architecture review
> (P4-1, P4-3). Wire-compatible with every earlier peer: no proto change, no `lib_schema_version`
> bump, no on-disk schema change — the keepalive is transport-level and the rest is local policy.
> - **A live session now ends itself when a cap prune eats deltas it has not sent.** The pump reads
> `seq > sentThruSeq`, which resumes SILENTLY above a pruned hole; the peer acks the later seqs
> and the pair is durably divergent for the whole life of that session. `needs_snapshot` (set in
> the prune's own transaction) only heals a RECONNECT, and nothing forced one — so on a stable
> LAN with a slow-but-alive peer the divergence was unbounded. Every pump iteration now compares
> the oplog horizon (`MIN(seq)`, one b-tree seek) against its sent watermark and throws
> `LocalDbOplogGapException` when deltas it still owes are gone. The horizon, not the flag,
> because the flag is also raised for reasons that do not invalidate the running session.
> - **The sync stream has HTTP/2 keepalive, and the server's single-stream guard is newest-wins.**
> Neither end ever timed out on silence (a converged pair is legitimately quiet), so a hard crash
> or partition of the dialling node left the passive node's handler parked in `MoveNext` on a
> half-open stream — holding the guard, reporting itself connected, and rejecting the rebooted
> peer's reconnects with `AlreadyExists`, indefinitely on an idle pair. The initiator now dials
> with `KeepAlivePingDelay` / `KeepAlivePingTimeout` (new options, 60s/20s, `Always` policy so
> idle connections ping too), and a fresh authenticated `Sync` cancels the incumbent and waits
> for it to unwind before starting — the guard serializes sessions, it was never a fence, and an
> authenticated same-key dialler is by definition the peer. An incumbent that will not yield
> within the takeover timeout still gets `AlreadyExists`, because two live sessions over one
> database is worse than a refused dial.
> - `0.3.1` (2026-08-18) — a faulting session flushes its control lane before cancelling its writer,
> so a locally-detected handshake mismatch actually reaches the peer instead of leaving it to
> reconnect-loop against a generic disconnect.
> - `0.3.0` (2026-08-15) — **the snapshot-resync flag is per-table.** On-disk bookkeeping schema
> goes to **v3** (new `__localdb_snapshot_state`, upgraded in place on open); wire-compatible with
> `0.1.x`/`0.2.x` peers, and `lib_schema_version` deliberately stays `1` because it is compared