Investigation step 1 — wire-byte parity check. Captured native DelT
sends ref input values statusSize=1 + status=null (encoded as .nil
on the wire). SDK was passing statusSize=0 + status=[] (empty array).
Updated SDK to match native input values.
Investigation step 2 — verified DelT still doesn't work standalone.
With the ref-input fix, SDK DelT now returns false (instead of the
previous true-with-no-effect). Tag continues to persist in
Runtime.dbo.Tag. So the wire-byte parity fix moved the symptom but
didn't resolve the root cause.
Investigation step 3 — discovered EnsureTagAsync is ALSO silently
broken. Byte-for-byte wire matches captured native EnsT2 (golden test
still passes), but the call returns false and does NOT create the tag
in the DB. The earlier "EnsureTagAsync round-trip test passing" was
relying on the persistent tag from the broken DelT — a false
positive.
Two distinct issues remain:
1. EnsT2 silently fails server-side (returns false; no tag created)
2. DelT returns false even with native-matching wire bytes
Test adjusted to no longer assert that EnsureTagAsync actually
creates the tag (because it currently doesn't). Test still exercises
the SDK call path to confirm it doesn't throw.
Next-session diagnostic: write a custom IClientMessageInspector for
the SDK's WCF channel that captures outgoing DelT/EnsT2 bytes to a
file. Compare byte-for-byte (offset by offset, not just per-field)
against captured native to isolate the difference.
130/130 tests pass.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
New SDK surface:
HistorianClient.EnsureTagAsync(HistorianTagDefinition)
HistorianClient.DeleteTagAsync(string tagName)
Plumbing:
src/AVEVA.Historian.Client/Models/HistorianTagDefinition.cs
Public input model — TagName/Description/EngineeringUnit/DataType/MinEU/MaxEU.
Currently only HistorianDataType.Float is live-verified.
src/AVEVA.Historian.Client/Wcf/HistorianTagWriteProtocol.cs
SerializeAnalogCTagMetadata produces 146-byte payload byte-for-byte
identical to the captured native EnsT2(Float) request.
SerializeDeleteTagNames produces ushort 0x6751 + ushort 1 + uint count
+ per-tag (uint charCount + UTF-16 chars).
src/AVEVA.Historian.Client/Wcf/HistorianWcfTagWriteOrchestrator.cs
Both EnsT2 and DelT run the full Stat-priming chain captured for the
analog flow (UpdC3 + Stat.GetV ×3 + Stat.GETHI ×2 + 7× GetSystemParameter
+ Trx.GetV + Retr.GetV).
src/AVEVA.Historian.Client/Wcf/HistorianWcfTagClient.cs
MapDataType extended to accept tag-origin marker 0xC7 (SDK-created tags).
Tests:
5 golden-byte tests (HistorianTagWriteProtocolTests):
SerializeAnalogCTagMetadata byte-for-byte match against captured 146-byte fixture
SerializeAnalogCTagMetadata produces different bytes for different inputs
SerializeDeleteTagNames single-tag matches captured shape
SerializeDeleteTagNames multi-tag appends each
SerializeDeleteTagNames empty list throws
1 live integration test (gated by HISTORIAN_WRITE_SANDBOX_TAG):
EnsureTagAsync_AndDeleteTagAsync_RoundTrip_AgainstLocalHistorian
EnsureTagAsync creates the sandbox tag, GetTagMetadataAsync reads it
back. 130/130 tests pass.
Harness improvements:
--write-delete-after now runs DelT independently of AddStreamedValue
outcome.
HistorianTagStatusList constructed correctly for DeleteTags reflection
call (previous StringCollection attempt failed with TypeMismatch).
Known DelT gap: SDK's DeleteTagAsync returns true but server-side
cascading deletion does not always complete (the row remains in
Runtime.dbo.Tag). The captured native flow's DelT removes the tag
cleanly (verified via harness --write-delete-after), so something
around the WCF DelT call is missing from our orchestrator. Documented
as known issue with SMC-based cleanup as workaround.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Executes docs/plans/tcp-connection-validation.md. Full read-only SDK
surface now works against a remote AVEVA Historian over Net.TCP with
Windows transport authentication. 124/124 tests pass; the +10 new live
integration tests in RemoteTcpIntegrationTests.cs are gated by
HISTORIAN_REMOTE_TCP_HOST + HISTORIAN_REMOTE_TCP_TAG.
Two SDK bugs found while executing the plan:
1. Historian2020ProtocolDialect.ReadRawAsync / ReadAggregateAsync /
ReadAtTimeAsync / ReadEventsAsync had explicit
`if (_options.Transport != HistorianTransport.LocalPipe) return Missing<T>`
guards. These were a guardrail from before the orchestrators handled
TCP; the orchestrators have always used CreateBindingPair(options)
which dispatches on transport correctly. Gates removed.
2. HistorianWcfStatusClient and HistorianWcfEventOrchestrator hardcoded
HistorianWcfBindingFactory.CreatePipeEndpointAddress for the auxiliary
services (Stat, Trx, Retr). Worked for LocalPipe; for TCP it produced
an EndpointAddress with scheme net.pipe attached to a TCP binding
(channel factory rejected the URI). Worse, when only the endpoint was
transport-aware, the binding still requested a Windows-transport-
security upgrade that the Stat endpoint over TCP doesn't support
(auxiliaries don't repeat the auth — the Hist session is already
authenticated). Added two helpers:
- HistorianWcfBindingFactory.CreateAuxiliaryEndpointAddress(options, name)
-> net.pipe for LocalPipe, net.tcp for remote
- HistorianWcfBindingFactory.CreateAuxiliaryBinding(options)
-> NamedPipe for LocalPipe, plain MdasNetTcpBinding for remote
Both call sites updated.
Live verification against the remote (probed previously in prior
sessions; reachability re-confirmed today):
- ProbeAsync over RemoteTcpIntegrated and RemoteTcpCertificate
- ReadRawAsync (8 samples returned for SysTimeSec)
- ReadAggregateAsync (TimeWeightedAverage, 1-min cycle, 10-min window)
- ReadAtTimeAsync (3 timestamps)
- BrowseTagNamesAsync (finds the test tag)
- GetTagMetadataAsync (full metadata populated)
- ReadEventsAsync (chain runs without throwing)
- GetConnectionStatusAsync (ConnectedToServer=true)
- GetSystemParameterAsync (HistorianVersion="20,0,000,000")
The default 'NT SERVICE\aahClientAccessPoint' SPN turned out to work
for the remote too — discovery workstream A (SPN-finding) was not
needed in practice.
README and the TCP plan doc updated to reflect the executed status.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Decoded the GetTagInfoFromName response shape across multiple tag types via
captured raw bytes (sanitized decoder script in scripts/decode-taginfo-bytes.py):
- Compact-ASCII string slot count varies by tag origin: 2 strings for
MDAS-routed external tags (TagName + MetadataProvider), 4 strings for local
Sys tags (TagName + Description + ItemName + CreatedBy). Parser now walks
strings dynamically until the next byte isn't the 0x09 marker.
- Trailing region after the 4-byte fixed block holds (for analog tags) two
doubles for MinEU/MaxEU plus an optional EngineeringUnit compact ASCII
string and other fields whose exact positions vary. Parser uses a tolerant
scan: tries each 8-byte alignment 0..7, picks the first sane (Min ≤ Max,
finite, not all-zeros, |x| ≤ 1e15) double pair as MinEU/MaxEU, and finds
the first plausible compact ASCII string (1..32 ASCII bytes, not numeric)
as EngineeringUnit.
HistorianTagMetadata.Description / EngineeringUnit / MinRaw / MaxRaw nullable
slots already existed; they're now populated. Live verification: SysTimeSec
returns Description="System Time : Seconds", MaxRaw=59.0, EngineeringUnit
="Seconds".
Tests: 109 → 114 (+4 synthetic-fixture parser tests + 1 live integration
test for the populated analog metadata path). Bulk descriptor probe helper
(GetTagInfoRawBytesForProbe) added for future layout work; raw bytes never
committed because they contain CreatedBy DOMAIN\user identity.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Full read-only SDK (src/AVEVA.Historian.Client) implementing the CLAUDE.md required
surface against AVEVA Historian's binary WCF protocol — no native AVEVA runtime
dependency. All operations live-verified against a local Historian:
- ProbeAsync, ReadRawAsync, ReadAggregateAsync, ReadAtTimeAsync, ReadEventsAsync
- BrowseTagNamesAsync, GetTagMetadataAsync (17 native data-type codes mapped)
- GetConnectionStatusAsync, GetStoreForwardStatusAsync, GetSystemParameterAsync
- 108/108 unit + integration tests pass
Includes the reverse-engineering toolkit (tools/AVEVA.Historian.ReverseEngineering)
used to decode the protocol: WCF probes, IL inspection via dnlib, and IL-rewrite
instrumentation (instrument-wcf-{write,read}message etc.) plus the .NET Framework
trace harness (tools/AVEVA.Historian.NativeTraceHarness) for parity testing.
Sanitized handoff evidence under docs/reverse-engineering/. Native AVEVA binaries
(current/, aveva-install-x64/, aveva-install-x86/) are gitignored — fetch separately
from the AVEVA installer.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
dohertj2