audit-core/workplans/AUDIT-WP-0005-postgres-store-and-production-deployment.md

---
id: AUDIT-WP-0005
type: workplan
title: "Deploy audit-core on Railiance with durable Postgres custody"
domain: infotech
repo: audit-core
status: proposed
owner: codex
topic_slug: netkingdom
created: "2026-08-10"
updated: "2026-08-10"
depends_on:
  - AUDIT-WP-0004
  - RAPP-POSTGRES-WP-0002
  - NK-WP-0024
state_hub_workstream_id: "7b24a844-c9f2-4d2d-ac7d-20978bdf6b38"
---

# AUDIT-WP-0005 - Postgres store and production deployment

## Goal

Put audit-core into production on Railiance with PostgreSQL as the custody
store, and prove the delivery path end to end.

This is first on the critical path: email-connect delivery, OpenBao sender
credentials, the user-engine runtime integrations, and the live failure matrix
all sit downstream of a receiver that actually holds evidence.

## Dependencies

- **AUDIT-WP-0004** — the receiver must route through the backend contract and
  return deliberate status codes before a Postgres backend is worth writing
  behind it, and before a failure matrix can distinguish a correct refusal
  from a crash.
- **RAPP-POSTGRES-WP-0002** — the database, the tenancy model, and the
  credential lane. T01 below can be drafted against the model as soon as
  RAPP-POSTGRES-WP-0002-T01 settles it; T02 needs a provisioned database.

## Boundaries

This workplan owns the Postgres backend implementation, audit-core's
deployment, and the live verification. It does not own the database platform,
its tenancy model, or its backup machinery — those belong to rapp-postgres.
Where audit-core needs a guarantee from the platform, it states the
requirement and consumes it; it does not implement it here.

## T01 - Implement the Postgres audit backend

```task
id: AUDIT-WP-0005-T01
status: done
priority: high
state_hub_task_id: "b1601d0b-922a-40f7-92c0-ea06af6c4468"
```

Implement `AuditBackend` against PostgreSQL, declaring an honest
`RetentionPolicy` — the custody class, retention window, and whether
immutability and tamper evidence are genuinely provided rather than aspired
to. If the schema does not prevent an operator from silently editing a
recorded event, the policy must not claim `immutable`.

Push idempotency into the database rather than a read-then-write in
application code: an insert conflicting on event ID must resolve atomically
into duplicate-accepted or conflict, with no window where two concurrent
identical events both write. Store the payload hash for conflict detection.

Handle connection lifecycle properly — pooling, reconnection after a database
restart, and a bounded statement timeout so a stalled write surfaces as
unavailable instead of hanging the request.

Own the migrations. The consuming service owns its schema; rapp-postgres owns
the space it runs in.

Done when the backend passes the same contract tests as the existing backends,
concurrent duplicate submissions produce exactly one record, and a database
restart mid-write does not produce an acknowledged-but-absent event.

Done 2026-08-10, built and verified against PostgreSQL 16 locally in Docker —
the Railiance cluster was not needed for any of it.

`tests/test_backend_conformance.py` is a single suite run against every
backend, so "the Postgres backend is done" means it satisfies the same
contract SQLite already does rather than having its own tests that happen to
be green. It skips cleanly when no server is reachable; `make pg-test-up` and
`make test-pg` run it. Suite 50 -> 71.

`RetentionPolicy` declares `immutable=True`, and that is earned: migration
0002 installs a trigger rejecting UPDATE and DELETE on the events table, so a
leaked runtime credential can append but cannot rewrite or erase the trail.
This materially narrows the residual risk ADR-0001 §5 called out — a leaked
credential could previously forge the audit record. `tamper_evidence` stays
False, because nothing here would *prove* a database owner had dropped the
trigger; hash-chaining or external anchoring would be needed and is not
implemented.

Migrations are ordered, recorded in `schema_migrations`, and idempotent.
Replay reconciles rather than duplicating — the piece deferred out of
WP-0004-T05 — and is tested to leave exactly one custody record.

Backend selection is by `AUDIT_CORE_DATABASE_URL`; falling back to SQLite logs
a warning, so a deployment that lost its URL is visible rather than quietly
running on the wrong store. End-to-end smoke through waitress against Postgres
confirmed accept, duplicate, cross-tenant refusal, read/write privilege
separation, visible redaction, secret-finding counters, and readiness
reporting `custody_class=archive`.

Also fixed: `audit_core.ingestion` had no `__main__` guard, so `python -m
audit_core.ingestion` silently did nothing.

Not covered here: behaviour across a real database failover, which needs the
cluster and belongs to T05.

## T02 - Provision storage through the platform lane

```task
id: AUDIT-WP-0005-T02
status: todo
priority: high
state_hub_task_id: "831b2472-0d80-4369-a5e3-eb08ef3526b1"
```

Declare audit-core's database requirement against rapp-postgres and take
delivery of a least-privilege runtime role through the OpenBao lane. The
runtime role connects; a separate role runs migrations; neither owns more than
it needs.

Verify audit-core's side of the isolation model: the runtime credential
reaches audit-core's data and nothing else, and rotation completes without a
delivery gap.

Done when audit-core runs against a provisioned database using a credential it
never received as a literal, and rotating that credential does not drop
events.

## T03 - Deploy the receiver

```task
id: AUDIT-WP-0005-T03
status: todo
priority: high
state_hub_task_id: "598af2ac-e772-4a4e-9a65-dde9d4ca167f"
```

Publish an immutable image — base pinned by digest, not a mutable tag, and
labelled with the build commit — and deploy on railiance01 with a Service,
health and readiness probes wired to the checks from WP-0004-T01, resource
requests and limits, a restricted security context, and a default-deny
NetworkPolicy admitting only user-engine as sender and the operator path for
reads.

State the rollback position: which image digest and which schema version the
deployment can return to, and whether the migration in T01 is reversible. A
rollback plan that assumes reversible migrations without checking is not a
plan.

The container currently runs as uid 10001 and expects a writable `/data`; once
custody is in Postgres that path should carry no durable state at all. Confirm
nothing of value is left on the pod filesystem.

Done when the receiver is reachable only by its declared peers, survives pod
restart and rescheduling without loss, and has a tested path back to the
previous version.

## T04 - Migrate existing SQLite records

```task
id: AUDIT-WP-0005-T04
status: todo
priority: medium
state_hub_task_id: "9010fb4a-a1b8-4ef7-b143-e33ca7cc0619"
```

Any events accepted by the pre-production SQLite receiver are audit records
and cannot simply be dropped. Move them into the Postgres store with their
original identifiers, timestamps, and payload hashes intact, or record an
explicit decision that they are development artifacts with no custody value.

Whichever holds, it must be written down — silently discarding accepted audit
events is the exact failure this service is meant to make impossible.

Done when the disposition of every pre-production record is either migrated
and verified, or explicitly and justifiably discarded.

## T05 - Run the live failure matrix

```task
id: AUDIT-WP-0005-T05
status: todo
priority: high
state_hub_task_id: "1da30fec-b9f1-4be0-b42c-15797a8c4392"
```

Exercise the deployed path: successful delivery; receiver timeout and
unavailability; bounded user-engine retry against each documented status code;
dead-letter visibility; operator replay and duplicate replay; redaction; and
correlation lookup. Include a database failover or restart during active
ingestion, and a credential rotation during active ingestion.

The controlling assertion is that one source outbox event produces exactly one
durable normalized event across retries, replay, and infrastructure
disruption — no loss, no duplication.

Hand non-secret evidence back to NK-WP-0024.

Done when the matrix has been run against the deployed system and each
outcome recorded, including any case where behaviour differed from the
documented contract.

## T06 - Operational handover

```task
id: AUDIT-WP-0005-T06
status: todo
priority: medium
state_hub_task_id: "0856c80d-abe1-4bff-ba8d-87295cf76819"
```

Document what an operator needs: how to look up an event by correlation ID,
how to inspect and replay dead-lettered events, how to rotate the sender
credential, what the alert conditions mean, and how to restore audit data from
a rapp-postgres backup.

Verify audit-core's recovery requirement against what rapp-postgres actually
provides — the retention window audit-core declares must not exceed the
retention the platform guarantees.

Done when the runbook exists and the restore path has been walked once.