Files
lmxopcua/docs/HistoricalDataAccess.md
Joseph Doherty 71339307fa Doc refresh (task #203) — driver docs split + drivers index + IHistoryProvider-aware HistoricalDataAccess
Restructure the driver-facing docs to match the OtOpcUa v2 multi-driver
reality (Galaxy, Modbus, S7, AB CIP, AB Legacy, TwinCAT, FOCAS, OPC UA Client
— 8 drivers total; Galaxy ships as three projects) and the capability-interface
architecture where every driver opts into IDriver + whichever of IReadable /
IWritable / ITagDiscovery / ISubscribable / IHostConnectivityProbe /
IPerCallHostResolver / IAlarmSource / IHistoryProvider / IRediscoverable it
supports. Doc scope follows the code: one-driver-specific docs scoped to that
driver, cross-driver concerns live once at the top level, per-driver specs
cross-link to docs/v2/driver-specs.md rather than duplicate.

What changed per file:

- docs/MxAccessBridge.md -> docs/drivers/Galaxy.md (git mv + rewrite): retitled
  "Galaxy Driver", reframed as one of seven drivers. Added Project Split table
  (Shared .NET Standard 2.0 / Host .NET 4.8 x86 / Proxy .NET 10) and Why
  Out-of-Process section citing both the MXAccess bitness constraint and Tier C
  stability isolation per docs/v2/plan.md section 4. Added IPC Transport
  section covering pipe naming, MessagePack framing, DACL that denies Admins,
  shared-secret handshake, heartbeat, and CallAsync<TReq,TResp> dispatch.
  Moved file paths from src/ZB.MOM.WW.LmxOpcUa.Host/MxAccess/* to
  src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Host/Backend/MxAccess/* and added the
  Shared + Proxy key-file tables. Added CapabilityInvoker + OTOPCUA0001
  analyzer callout. Cross-linked to drivers/README.md, Galaxy-Repository.md,
  HistoricalDataAccess.md.

- docs/GalaxyRepository.md -> docs/drivers/Galaxy-Repository.md (git mv +
  rewrite): retitled "Galaxy Repository — Tag Discovery for the Galaxy
  Driver", opened with a comparison table showing how every driver's
  ITagDiscovery source is different (AB CIP @tags walker, TwinCAT
  SymbolLoaderFactory, FOCAS CNC queries, OPC UA Client Session.Browse, etc).
  Repositioned GalaxyRepositoryService as the Galaxy driver's
  ITagDiscovery.DiscoverAsync implementation. Updated paths to
  Driver.Galaxy.Host/Backend/GalaxyRepository/*. Added IRediscoverable section
  covering the on-change-redeploy IPC path.

- docs/drivers/README.md (new): index with ground-truth driver table —
  project path, stability tier, wire library, capability-interface list, and
  one notable quirk per driver. Verified against the driver csproj files and
  class declarations on focas-pr3-remaining-capabilities (the most recent
  branch containing every driver). Galaxy gets its own dedicated docs; the
  other seven drivers cross-link to docs/v2/driver-specs.md. Lists the full
  Core.Abstractions capability surface, DriverTypeRegistry, CapabilityInvoker,
  and OTOPCUA0001 analyzer.

- docs/HistoricalDataAccess.md (rewrite): reframed around IHistoryProvider as
  a per-driver optional capability interface. Replaced v1 HistorianPluginLoader
  / AvevaHistorianPluginEntry plugin architecture with the v2 story —
  Historian.Aveva was merged into Driver.Galaxy.Host/Backend/Historian/ and
  IPC-forwarded through GalaxyProxyDriver. Documented all four IHistoryProvider
  methods (ReadRawAsync / ReadProcessedAsync / ReadAtTimeAsync /
  ReadEventsAsync), CapabilityInvoker wrapping with DriverCapability.HistoryRead,
  and the per-driver coverage matrix (Galaxy + OPC UA Client implement; the
  six protocol drivers don't and return BadHistoryOperationUnsupported). Kept
  the cluster-failover + health-counter + quality-mapping detail for the
  Galaxy Historian implementation. Flagged one gap: Proxy forwards all four
  history message kinds but the Host-side HistoryAggregateType -> AnalogSummary
  column mapping may surface GalaxyIpcException{Code="not-implemented"} on a
  given branch until the Phase 2 Galaxy out-of-process gate lands.

Driver list built against ground truth (src on focas-pr3-remaining-capabilities):
  Driver.Galaxy.{Shared,Host,Proxy}, Driver.Modbus, Driver.S7, Driver.AbCip,
  Driver.AbLegacy, Driver.TwinCAT, Driver.FOCAS, Driver.OpcUaClient.
Capability interface lists verified against each *Driver.cs class declaration.
Aveva Historian ported to Driver.Galaxy.Host/Backend/Historian/; no separate
Historian.Aveva assembly on v2 branches.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-20 01:33:53 -04:00

124 lines
11 KiB
Markdown

# Historical Data Access
OPC UA HistoryRead is a **per-driver optional capability** in OtOpcUa. The Core dispatches HistoryRead service calls to the owning driver through the `IHistoryProvider` capability interface (`src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/IHistoryProvider.cs`). Drivers that don't implement the interface return `BadHistoryOperationUnsupported` for every history call on their nodes; that is the expected behavior for protocol drivers (Modbus, S7, AB CIP, AB Legacy, TwinCAT, FOCAS) whose wire protocols carry no time-series data.
Historian integration is no longer a separate bolt-on assembly, as it was in v1 (`ZB.MOM.WW.LmxOpcUa.Historian.Aveva` plugin). It is now one optional capability any driver can implement. The first implementation is the Galaxy driver's Wonderware Historian integration; OPC UA Client forwards HistoryRead to the upstream server. Every other driver leaves the capability unimplemented and the Core short-circuits history calls on nodes that belong to those drivers.
## `IHistoryProvider`
Four methods, mapping onto the four OPC UA HistoryRead service variants:
| Method | OPC UA service | Notes |
|--------|----------------|-------|
| `ReadRawAsync` | HistoryReadRawModified (raw subset) | Returns `HistoryReadResult { Samples, ContinuationPoint? }`. The Core handles `ContinuationPoint` pagination. |
| `ReadProcessedAsync` | HistoryReadProcessed | Takes a `HistoryAggregateType` (Average / Minimum / Maximum / Total / Count) and a bucket `interval`. Drivers that can't express an aggregate throw `NotSupportedException`; the Core translates that into `BadAggregateNotSupported`. |
| `ReadAtTimeAsync` | HistoryReadAtTime | Default implementation throws `NotSupportedException` — drivers without interpolation / prior-boundary support leave the default. |
| `ReadEventsAsync` | HistoryReadEvents | Historical alarm/event rows, distinct from the live `IAlarmSource` stream. Default throws; only drivers with an event historian (Galaxy's A&E log) override. |
Supporting DTOs live alongside the interface in `Core.Abstractions`:
- `HistoryReadResult(IReadOnlyList<DataValueSnapshot> Samples, byte[]? ContinuationPoint)`
- `HistoryAggregateType` — enum `{ Average, Minimum, Maximum, Total, Count }`
- `HistoricalEvent(EventId, SourceName?, EventTimeUtc, ReceivedTimeUtc, Message?, Severity)`
- `HistoricalEventsResult(IReadOnlyList<HistoricalEvent> Events, byte[]? ContinuationPoint)`
## Dispatch through `CapabilityInvoker`
All four HistoryRead surfaces are wrapped by `CapabilityInvoker` (`Core/Resilience/CapabilityInvoker.cs`) with `DriverCapability.HistoryRead`. The Polly pipeline keyed on `(DriverInstanceId, HostName, DriverCapability.HistoryRead)` provides timeout, circuit-breaker, and bulkhead defaults per the driver's stability tier (see [docs/v2/driver-stability.md](v2/driver-stability.md)).
The dispatch point is `DriverNodeManager` in `ZB.MOM.WW.OtOpcUa.Server`. When the OPC UA stack calls `HistoryRead`, the node manager:
1. Resolves the target `NodeHandle` to a `(DriverInstanceId, fullReference)` pair.
2. Checks the owning driver's `DriverTypeMetadata` to see if the type may advertise history at all (fast reject for types that never implement `IHistoryProvider`).
3. If the driver instance implements `IHistoryProvider`, wraps the `ReadRawAsync` / `ReadProcessedAsync` / `ReadAtTimeAsync` / `ReadEventsAsync` call in `CapabilityInvoker.InvokeAsync(... DriverCapability.HistoryRead ...)`.
4. Translates the `HistoryReadResult` into an OPC UA `HistoryData` + `ExtensionObject`.
5. Manages the continuation point via `HistoryContinuationPointManager` so clients can page through large result sets.
Driver-level history code never sees the continuation-point protocol or the OPC UA stack types — those stay in the Core.
## Driver coverage
| Driver | Implements `IHistoryProvider`? | Source |
|--------|:------------------------------:|--------|
| Galaxy | Yes — raw, processed, at-time, events | `aahClientManaged` SDK (Wonderware Historian) on the Host side, forwarded through the Proxy's IPC |
| OPC UA Client | Yes — raw, processed, at-time, events (forwarded to upstream) | `Opc.Ua.Client.Session.HistoryRead` against the remote server |
| Modbus | No | Wire protocol has no time-series concept |
| Siemens S7 | No | S7comm has no time-series concept |
| AB CIP | No | CIP has no time-series concept |
| AB Legacy | No | PCCC has no time-series concept |
| TwinCAT | No | ADS symbol reads are point-in-time; archiving is an external concern |
| FOCAS | No | Default — FOCAS has no general-purpose historian API |
## Galaxy — Wonderware Historian (`aahClientManaged`)
The Galaxy driver's `IHistoryProvider` implementation lives on the Host side (`.NET 4.8 x86`) in `src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Host/Backend/Historian/`. The Proxy's `GalaxyProxyDriver.ReadRawAsync` / `ReadProcessedAsync` / `ReadAtTimeAsync` / `ReadEventsAsync` each serializes a `HistoryRead*Request` and awaits the matching `HistoryRead*Response` over the named pipe (see [drivers/Galaxy.md](drivers/Galaxy.md#ipc-transport)).
Host-side, `HistorianDataSource` uses the AVEVA Historian managed SDK (`aahClientManaged.dll`) to query historical data via a cursor-based API through `ArchestrA.HistorianAccess`:
- **`HistoryQuery`** — raw historical samples (timestamp, value, OPC quality)
- **`AnalogSummaryQuery`** — pre-computed aggregates (Average, Minimum, Maximum, ValueCount, First, Last, StdDev)
The SDK DLLs are pulled into the Galaxy.Host project at build time; the Server and every other driver project remain SDK-free.
> **Gap / status note.** The raw SDK wrapper (`HistorianDataSource`, `HistorianClusterEndpointPicker`, `HistorianHealthSnapshot`, etc.) has been ported from the v1 `ZB.MOM.WW.LmxOpcUa.Historian.Aveva` plugin into `Driver.Galaxy.Host/Backend/Historian/`. The **IPC wire-up** — `HistoryReadRequest` / `HistoryReadResponse` message kinds, Proxy-side `ReadRawAsync` / `ReadProcessedAsync` / `ReadAtTimeAsync` / `ReadEventsAsync` forwarding — is in place on `GalaxyProxyDriver`. What remains to close on a given branch is Host-side **mapping of `HistoryAggregateType` onto the `AnalogSummaryQuery` column names** (done in `GalaxyProxyDriver.MapAggregateToColumn`; the Host side must mirror it) and the **end-to-end integration test** that was held by the v1 plugin suite. Until those land on a given driver branch, history calls against Galaxy may surface `GalaxyIpcException { Code = "not-implemented" }` or backend-specific errors rather than populated `HistoryReadResult`s. Track the remaining work against the Phase 2 Galaxy out-of-process gate in `docs/v2/plan.md`.
### Aggregate function mapping
`GalaxyProxyDriver.MapAggregateToColumn` (Proxy-side) translates the OPC UA Part 13 standard aggregate enum onto `AnalogSummaryQuery` column names consumed by `HistorianDataSource.ReadAggregateAsync`:
| `HistoryAggregateType` | Result Property |
|------------------------|-----------------|
| `Average` | `Average` |
| `Minimum` | `Minimum` |
| `Maximum` | `Maximum` |
| `Count` | `ValueCount` |
`HistoryAggregateType.Total` is **not supported** by Wonderware `AnalogSummary` and raises `NotSupportedException`, which the Core translates to `BadAggregateNotSupported`. Additional OPC UA aggregates (`Start`, `End`, `StandardDeviationPopulation`) sit on the Historian columns `First`, `Last`, `StdDev` and can be exposed by extending the enum + mapping together.
### Read-only cluster failover
`HistorianConfiguration.ServerNames` accepts an ordered list of cluster nodes. `HistorianClusterEndpointPicker` iterates the list in configuration order, marks failed nodes with a `FailureCooldownSeconds` window, and re-admits them when the cooldown elapses. One picker instance is shared by the process-values connection and the event-history connection (two SDK silos), so a node failure on one silo immediately benches it for the other. `FailureCooldownSeconds = 0` disables the cooldown — the SDK's own retry semantics are the sole gate.
Host-side cluster health is surfaced via `HistorianHealthSnapshot { NodeCount, HealthyNodeCount, ActiveProcessNode, ActiveEventNode, Nodes }` and forwarded to the Proxy so the Admin UI Historian panel can render a per-node table. `HealthCheckService` flips overall service health to `Degraded` when `HealthyNodeCount < NodeCount`.
### Runtime health counters
`HistorianDataSource` maintains per-read counters — `TotalQueries`, `TotalSuccesses`, `TotalFailures`, `ConsecutiveFailures`, `LastSuccessTime`, `LastFailureTime`, `LastError`, `ProcessConnectionOpen`, `EventConnectionOpen` — so the dashboard can distinguish "backend loaded but never queried" from "backend loaded and queries are failing". `LastError` is prefixed with the read path (`raw:`, `aggregate:`, `at-time:`, `events:`) so operators can tell which silo is broken. `HealthCheckService` degrades at `ConsecutiveFailures >= 3`.
### Quality mapping
The Historian SDK returns standard OPC DA quality values in `QueryResult.OpcQuality` (UInt16). The low byte flows through the shared `QualityMapper` pipeline (`MapFromMxAccessQuality``MapToOpcUaStatusCode`):
| OPC Quality Byte | OPC DA Family | OPC UA StatusCode |
|------------------|---------------|-------------------|
| 0-63 | Bad | `Bad` (with sub-code when an exact enum match exists) |
| 64-191 | Uncertain | `Uncertain` (with sub-code when an exact enum match exists) |
| 192+ | Good | `Good` (with sub-code when an exact enum match exists) |
See `Domain/QualityMapper.cs` and `Domain/Quality.cs` in `Driver.Galaxy.Host` for the full table.
## OPC UA Client — upstream forwarding
The OPC UA Client driver (`Driver.OpcUaClient`) implements `IHistoryProvider` by forwarding each call to the upstream server via `Session.HistoryRead`. Raw / processed / at-time / events map onto the stack's native HistoryRead details types. Continuation points are passed through — the Core's `HistoryContinuationPointManager` treats the driver as an opaque pager.
## Historizing flag and AccessLevel
During variable node creation, drivers that advertise history set:
```csharp
if (attr.IsHistorized)
accessLevel |= AccessLevels.HistoryRead;
variable.Historizing = attr.IsHistorized;
```
- **`Historizing = true`** — tells OPC UA clients that the node has historical data available.
- **`AccessLevels.HistoryRead`** — enables the `HistoryRead` access bit. The OPC UA stack checks this bit before routing history requests to the Core dispatcher; nodes without it are rejected before reaching `IHistoryProvider`.
The `IsHistorized` flag originates in the driver's discovery output. For Galaxy it comes from the repository query detecting a `HistoryExtension` primitive (see [drivers/Galaxy-Repository.md](drivers/Galaxy-Repository.md)). For OPC UA Client it is copied from the upstream server's `Historizing` property.
## Configuration
Driver-specific historian config lives in each driver's `DriverConfig` JSON blob, validated against the driver type's `DriverConfigJsonSchema` in `DriverTypeRegistry`. The Galaxy driver's historian section carries the fields exercised by `HistorianConfiguration``ServerName` / `ServerNames`, `FailureCooldownSeconds`, `IntegratedSecurity` / `UserName` / `Password`, `Port` (default `32568`), `CommandTimeoutSeconds`, `RequestTimeoutSeconds`, `MaxValuesPerRead`. The OPC UA Client driver inherits its timeouts from the upstream session.
See [Configuration.md](Configuration.md) for the schema shape and validation path.