AUDIT-WP-0005-T01, built and verified against PostgreSQL 16 locally in
Docker; the Railiance cluster was not needed.
tests/test_backend_conformance.py is one 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 green tests. It skips cleanly with no
server reachable; make pg-test-up and make test-pg run it. Suite 50 -> 71.
RetentionPolicy declares immutable=True and earns it: 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. That materially
narrows the residual risk ADR-0001 section 5 called out. 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.
Idempotency is one statement (INSERT ... ON CONFLICT DO NOTHING RETURNING),
verified to behave identically to the SQLite backend under 12 concurrent
submissions of the same event. Migrations are ordered, recorded 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; the SQLite fallback logs a
warning so a deployment that lost its URL is visible rather than quietly
running on the wrong store.
Also fixed: ingestion had no __main__ guard, so python -m audit_core.ingestion
silently did nothing. Found during end-to-end smoke.
Counting semantics documented: occurrences counts transmissions, not stored
events, so a retry of a secret-shaped field increments it again. That is the
sender behaviour being optimized away.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
AUDIT-WP-0004-T04, closing the workplan.
Decision (Bernd): default to redaction, allow rejection per sender. Losing an
audit record over one field is worse than storing it masked, but a
higher-assurance channel must be able to refuse rather than mask. secret_policy
is set per sender identity in AUDIT_CORE_SENDERS and defaults to redact.
Detection now covers the whole payload at any depth, including lists, rather
than only the top level of data. Under redaction the value is masked and the
key is preserved: dropping the key would hide that the sender transmitted the
field at all, which is exactly what an operator needs in order to stop it. The
stored record carries details.redaction with policy and affected paths, so a
reader never has to infer whether what they see is what was sent.
Idempotency is unaffected - the payload hash is taken over the original request
body, so redaction is deterministic and a resubmission still reconciles as a
duplicate.
Both outcomes are counted durably by sender, source, action and field path,
exposed at GET /v1/secret-findings. Per-path aggregation is the point: the
actionable unit is "stop emitting data.auth.token on membership.added", not
"there were 47 redactions". Counters survive restart because the fix they drive
lives in another service.
Contract doc updated to match. Tests 46 -> 50. WP-0004 is finished.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
