tidaldb/docs/planning/milestone-4/phase-3.md
jordan fe8d0c87e7 harden: restore CI verification, remove four wire-level fabrications, instrument the 401 path
Implements tmp/tidaldb-fleet-hardening (20 planned tasks + 2 found by measurement).

Ring 0 — restore verification. .woodpecker.yaml step pods ran at the namespace
default of 1500m/2Gi, which OOMKilled a prior pipeline and starved the release
gate past its budget. Both push-path steps now declare
backend_options.kubernetes.resources as two YAML anchors declared once on their
first consuming step. The values are CALIBRATED against measured free node
capacity, not against the LimitRange max: `requests: cpu 2` (this roadmap's
original figure) fits on NO node and would sit Pending forever, because
`ci-build-bounds` grants permission and the nodes supply capacity, and those are
not the same thing.

The `nightly` cron described in this file for 216 days was never created, so
tier-3 chaos, the fault classes, mTLS and the PITR test produced exactly zero
signal while reading like standing coverage. nightly-chaos and
nightly-security-ops now alias the anchors and have budgets matching the gate
(their 120/90 were TIGHTER on the same runner, so they would have failed
nightly for a budget reason, not a correctness one). nightly-soak is REMOVED,
not scheduled: it drives 1000 rps for 600s gating on p99 <= 250ms, and the best
node has 1700m free CPU, so it would fail on starvation rather than regression —
manufacturing a nightly false alarm. Its commands move verbatim to
docs/runbooks/nightly-soak.md.

Ring 1 — four fabrications removed from the wire.
- scatter_merge sorted and truncated without re-stamping rank, so /feed and
  /search returned 1,1,2 under full placement. Reuses merge_cross_shard's
  existing stamp; asserted on BOTH the multi-group merge path and the
  single-group [only] fast path that bypasses it.
- aggregate_region_row's None arm invented `applied_events: 0` plus a deficit
  derived from it. applied_events/lag_events are now Option<u64>, null on the
  wire. leader_last_seq was also unwrap_or(0), so a node that could not reach
  the LEADER computed 0 - applied = 0 for every region and reported a converged
  cluster it had never measured — a fabrication pointing the dangerous way.
- tidalctl inferred NO REPORT from `applied == 0 && lag > 0`. That heuristic was
  actively hiding the PVC-wipe shape: a measured zero with a real deficit
  rendered as "no report" instead of BEHIND. Now read off the wire; converged
  exits 0, partitioned still exits nonzero.
- /sharded/* answered 201/204 for single-copy writes with nothing anywhere
  saying so. Now requires `x-tidal-ack: local`, rejecting with 400 via the
  existing invalid_input path. Six call sites migrated, not the two this
  roadmap predicted — including docs/runbooks/cluster.md §16.3, which told
  operators to run a quorum-write probe via POST /sharded/items. That probe
  cannot verify quorum: the surface applies locally with no WAL append. It was
  used as the safety check between every step of a staged deploy earlier today.

Ring 2 — observability. JSON_LOGS was already implemented and the deployment
simply never asked for it; the StatefulSet now sets it, plus
TIDAL_SERVICE_NAME=tidaldb because enabling it silently renames the
VictoriaLogs `service` stream field and would have blinded every query keyed on
it. Adds tidaldb_usearch_replicated_vectors_total, incremented on BOTH the
origin (wal_blob_first -> Ok(Some)) and the follower apply path — counting only
the origin would mean each vector lands on exactly one node, replicas never
agree, and the alert built on it pages forever.

Found by measurement, not planned: the 401 path discarded every fact about
every rejection. Traefik has served 101,858 rejected requests to the public
ingress — 87.6% of all its traffic — with no record of who or why anywhere.
unauthorized_response now emits reason (missing_token vs invalid_token, the
distinction that separates a scanner from a rotation that missed a consumer)
and the forwarded client. The token is never logged.

Also: scripts/restore-fleet.sh --cluster started the soak monitor while
deliberately leaving its gate suspended, orphaning a watcher that has reported
"0/30 green nights" for 13 days. The pair now moves together. Doc-guard's
three-warning backlog is cleared with real backfill for M4/M6/M12.

Verified: fmt clean; clippy 5 crates 0 new warnings (74 vs 74 baseline,
counted in a detached worktree at HEAD); lib 2110 passed; cluster_sharding 5;
cluster_runbook 10; tidalctl 38; doc-guard 0 warnings. Playwright 32/34 with
the two remaining failures asserting the rank fix against the not-yet-rolled
image — they are the post-deploy proof.
2026-08-30 20:55:58 -06:00

76 lines
4.4 KiB
Markdown
Raw Permalink Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

# m4p3 — Policy Enforcement and Audit (✅ COMPLETE 2026-02-21)
Phase spec and acceptance criteria: [ROADMAP · Milestone 4 · Phase 3](../ROADMAP.md).
Milestone index: [README.md](README.md). Backfilled record.
## What shipped
1. **Policy evaluation on the write path** (`tidal/src/session/policy.rs`).
Every `session_signal` call is checked before any state mutation. The
evaluator returns a typed `PolicyViolation { kind, .. }` rather than a
stringly-typed reason. The four kinds M4 shipped:
| `PolicyViolationKind` | Trigger |
|-----------------------|---------|
| `Denied` | signal type appears in `denied_signals` |
| `NotAllowed` | `allowed_signals` is non-empty and the type is absent from it |
| `CountCap` | `signals_written` reached `max_signals_per_session` |
| `Expired` | wall clock passed `max_session_duration` |
2. **Error surface** (`tidal/src/db/sessions.rs:405-417`). `Expired` maps to
`TidalError::SessionExpired`; every other kind maps to
`TidalError::PolicyViolation` (`tidal/src/schema/error.rs:123`). A rejected
write mutates no session signal state — only the rejection counter and the
audit log advance.
3. **Bounded audit log** (`tidal/src/session/audit.rs`). `AuditEntry` carries
`timestamp_ns`, the signal type, an `accepted` flag, an `AuditKind`, and an
optional `reason`. It is a `VecDeque` capped at `MAX_AUDIT_ENTRIES = 10_000`;
past the cap the oldest entries are evicted and the snapshot's
`audit_truncated` flag is set, so a reader can tell a complete log from a
truncated one instead of silently believing a partial record.
4. **`db.session_audit(session_id)`** reads the live log for an active session;
for a closed session the log ships inside the archived `SessionSnapshot`
(`audit_log` field), so it is still readable after close and after restart.
## Evidence
| Criterion | Proof |
|-----------|-------|
| A denied signal is rejected, counted, and audited with a reason | `m4_uat.rs::step4_policy_rejects_denied_signal` — asserts `signals_rejected == 1`, `signals_written == 0`, `audit.len() == 1`, `!audit[0].accepted`, `audit[0].reason.is_some()` |
| A signal absent from a non-empty allow list is rejected | `m4_uat.rs::step5_policy_rejects_non_allowed_signal` |
| Accepted writes are audited as accepted | `m4_uat.rs::step3_session_signal_and_audit` |
| Truncation is observable, not silent | `session_durability.rs::audit_truncation_marker_set_when_cap_exceeded` |
| Audit survives close | `m4_uat.rs::step7_closed_session_snapshot`, `session_durability.rs::archived_session_readable_after_close_and_reopen` |
## Divergence from the plan
- **Typed kinds, not free-text reasons.** The ROADMAP specified
`AuditEntry = { timestamp, signal_type, outcome: Accepted | Rejected(reason) }`
and a `reason: String` on the error. Shipped design keeps the human-readable
reason but adds `PolicyViolationKind` and `AuditKind` enums, so callers branch
on a variant instead of matching on prose. This is strictly better and is what
M9/M10 later extended.
- **The `< 1 µs` policy-evaluation criterion has no recorded measurement.** The
ROADMAP marks it `[x]` "(benchmarked)". It is a `HashMap` lookup on the write
path, which makes the claim plausible, but no benchmark isolates it and no
recorded run exists. `tidal/benches/session.rs::session_signal` measures the
whole write including WAL, not policy evaluation alone. Treat the figure as
unevidenced.
- **The property test in the ROADMAP criteria is not present as a property
test.** "For any sequence of allowed and denied signal writes, the audit log
exactly matches the write outcomes and no denied signal modifies session
state" is proven by the concrete `m4_uat.rs` steps 35 and by
`session_durability.rs`, not by a `proptest`. The invariant is covered; the
stated *form* (randomized property test) was not built.
## Extended later
M9/M10 governance (`d8e4083`) added seven further `PolicyViolationKind` variants
`CommunityWriteDenied`, `CommunityWriteNotAllowed`, `ReadDenied`,
`ReadNotAllowed`, `AttributeReadDenied`, `AttributeReadNotAllowed`,
`ProfileOverrideNotAllowed` — and the matching `AuditKind` variants
(`ReadDenied`, `AttributeReadDenied`, `ProfileOverrideRejected`) plus the
`overrides_rejected` counter on `SessionSnapshot`. The M4 mechanism is the one
they extended: read-path and community policy reuse this evaluator and this
audit log rather than adding a parallel one.