Phase 4 of the ClusterClient -> gRPC migration deleted the Akka transports
but left the naming behind: `ClusterClientSiteAuditClient` was transport-
agnostic and worked unchanged, so it survived the deletion under a name
that now describes a transport the repo no longer has. Same for a scatter
of doc-comments still framing gRPC as "the new transport" beside an Akka
one that is gone.
Renames it to `SiteCommunicationAuditClient` (and its test file) and
rewrites the stale comments to describe the single transport that exists.
Also tightens CLAUDE.md: drops the self-describing directory listing and
the 27-component enumeration in favour of the non-obvious parts only.
Behaviour-neutral: names and prose only. Recorded as the Phase 4
follow-up in docs/plans/2026-07-22-clusterclient-to-grpc-plan.md.
Central now ALSO listens for the seven site→central control messages over
gRPC, alongside the existing ClusterClient path. Nothing flips to gRPC yet —
sites keep CentralTransport=Akka (T1A.3's job); central simply starts also
accepting.
- CentralControlGrpcService (Communication.Grpc): decodes each RPC onto the
SAME in-process message the ClusterClient path carries, Asks the existing
CentralCommunicationActor (zero handler-logic changes), encodes the reply via
the T1A.1 mapper. Readiness-gated like SiteStreamGrpcServer.SetReady —
Unavailable until AkkaHostedService hands the actor over. Heartbeat stays
fire-and-forget (Tell, always-OK, never gated on readiness). Ingest reuses the
shared SiteStreamGrpcServer.AuditIngestAskTimeout constant. Fault→status
mapping is retry-aware: Unavailable (never dispatched, safe to cross-node
retry) vs DeadlineExceeded/Internal (it ran, do not re-send elsewhere).
- CentralControlAuthInterceptor (Host): a SEPARATE interceptor class, not a
variant constructor on ControlPlaneAuthInterceptor. Central's model is per-site
(verify the Bearer token against the key for the site in the required
x-scadabridge-site header, via ISitePskProvider) where a site verifies its one
own-key — a genuinely different model. Fail-closed on every branch: missing or
blank header, unresolvable key, and mismatched token all → PermissionDenied,
never pass-through. One public constructor only (the explicit-prefix ctor is
internal), pinned by a reflection test — a second public ctor makes
Grpc.AspNetCore's GetFactory() throw per-call and silently disables the gate.
- Explicit Kestrel h2c listener on new option ScadaBridge:Node:CentralGrpcPort
(default 8083, symmetric with sites), mirroring the Site branch. Additive to
central's :5000 HTTP/1 surface, which is untouched — gRPC does NOT go through
Traefik (HTTP/1 only). Registered by type on AddGrpc; service mapped with
MapGrpcService. Port range-validated by NodeOptionsValidator.
- Rig: publish the central gRPC port 9013:8083 / 9014:8083 on both central nodes
so a later task can exercise it.
Tests: CentralControlEndToEndTests (Host.Tests, TestServer + real interceptor +
real service over a stub actor) proves auth positives/negatives are
distinguishable and covers unary + the ingest bridge shapes; the interceptor is
registered BY TYPE, never in DI. CentralControlAuthInterceptorTests pins the
per-site gate + one-public-ctor invariant. CentralControlGrpcServiceTests
(Communication.Tests, TestKit) covers the readiness gate, fire-and-forget
heartbeat, and the DeadlineExceeded-vs-Unavailable status mapping. No active
<Protobuf> item. Communication.Tests (356) + Host.Tests (384) green.
Joseph Doherty