The D2 storage-engine-pipe wall is WCF-transport-specific. On the 2023 R2 gRPC
front door, TransactionService is a first-class service AND the gateway to the
storage engine, so the Open2 storage-session GUID (uppercase) is accepted
directly as strHandle with no legacy pipe.
Live-verified against the real 2023 R2 server over a write-enabled (0x401) gRPC
session: AddNonStreamValuesBegin returns a real strTransactionId, and
AddNonStreamValuesEnd(bCommit=false) discards it cleanly (no data written). On
2020 WCF the same op returns UnknownClient(51) for every handle + priming chain.
- HistorianGrpcRevisionProbe + grpc-revision-probe CLI command + gated test
NonStreamedWriteTransaction_OverGrpc_BeginsAndDiscards (live pass).
- HistorianGrpcHandshake.OpenSession gains an optional connectionMode param
(default read-only 0x402; pass 0x401 for write-enabled) — non-breaking.
- Docs: revision-write-path.md "the wall is gone" section; roadmap M3 section,
R3.1-R3.3 rows, one-glance table, and status note updated honestly.
Not yet shipped: the AddNonStreamValues btInput VTQ buffer is uncaptured (never
guess wire bytes), so no value-commit is implemented. Scope is non-streamed
ORIGINAL backfill; revision EDITS (R4.2) remain pipe-only even on gRPC.
272 unit tests pass; sanitization scan clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Routes HistorianClient.GetTagMetadataAsync over gRPC when Transport==RemoteGrpc,
via the new Grpc/HistorianGrpcTagClient calling RetrievalService.GetTagInfosFromName
(the plural string-handle metadata op).
- String handle = the Open2 storage-session GUID formatted uppercase (the format
that resolves the native string-handle path); threaded out of the shared handshake
via a new HistorianGrpcHandshake.Session { ClientHandle, StorageSessionId, StringHandle }.
- Request btTagNames = uint count + per-name(uint charCount + UTF-16LE) — golden-byte
unit-tested (BuildTagNamesBuffer).
- Response btTagInfos = uint count + CTagMetadata records — decoded by the existing
HistorianTagQueryProtocol.ParseGetTagInfoResponse; data type via the shared MapDataType.
The 2020 WCF string-handle wall does NOT apply on the gRPC front door, as the
string-handle-wall RE note predicted. LIVE-VERIFIED against a real 2023 R2 server:
GetTagMetadataAsync returns the requested tag with a valid decoded data type.
216 unit tests pass. Captured framing confirmed live then discarded; no tag names
or identities committed.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Roadmap docs/plans/hcal-roadmap.md, milestone M0 (gRPC parity for the DONE
surface). Now unblocked for live verification by a reachable 2023 R2 server.
- R0.4 Probe over gRPC: new HistorianGrpcProbe calls History/Retrieval/Status
GetInterfaceVersion (unauthenticated). ProbeAsync routes over gRPC when
Transport==RemoteGrpc. LIVE-VERIFIED against a real 2023 R2 server — needs no
credentials (runs before the auth loop), so it works despite the auth blocker.
- R0.3 System parameter over gRPC: new HistorianGrpcStatusClient calls
StatusService.GetSystemParameter over the authenticated session; routed in the
dialect. Built + unit-tested (request/response field mapping pinned).
Live-verification pending an auth fix (see below).
- Extracted the proven auth handshake from HistorianGrpcReadOrchestrator into
shared Grpc/HistorianGrpcHandshake (reused by read + status + future
browse/metadata). Repointed the IL structural guardrail test to it.
- Diagnostics: round-failure now decodes the native server error + hex/ASCII
preview (HistorianNativeHandshake.DescribeError). This surfaced the live auth
blocker as SEC_E_LOGON_DENIED (0x8009030C) at NTLM round 1 — framing is correct,
the credential did not validate. Probable cause: stale file password or NAM-domain
NTLM restriction (Kerberos/RDP works, NTLM denied; no SPN path over the tunnel).
216 unit tests pass; live gRPC probe passes. Sanitization scan clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC
Joseph Doherty