# Wonderware Historian Backend — RETIRED

> **This backend has been retired.** The bespoke Wonderware TCP/ArchestrA historian sidecar
> (`OtOpcUaWonderwareHistorian`) and its `Driver.Historian.Wonderware*` projects — plus the vestigial
> `Historian.Wonderware` driver type — were removed. **HistorianGateway is now the sole historian
> backend** for OtOpcUa (read, alarm-write, and continuous historization).

## What replaced it

OtOpcUa now consumes the **`ZB.MOM.WW.HistorianGateway`** sidecar through the Gitea-feed
**`ZB.MOM.WW.HistorianGateway.Client`** gRPC package (`historian_gateway.v1`), behind the
`IHistorianGatewayClient` seam in `ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway`:

- **HistoryRead** → `GatewayHistorianDataSource` over the `ServerHistorian` appsettings section.
- **Alarm history** → `GatewayAlarmHistorianWriter` (the gateway `SendEvent` path) behind the durable
  `SqliteStoreAndForwardSink`; alarm-history `ReadEvents` needs the gateway running
  `RuntimeDb:EventReadsEnabled=true`.
- **Continuous historization** → a crash-safe FasterLog outbox + `ContinuousHistorizationRecorder`
  draining to the gateway's `WriteLiveValues` (`ContinuousHistorization` section); needs the gateway
  running `RuntimeDb:Enabled=true`.
- **Tag provisioning** → `AddressSpaceApplier` fires a non-blocking `IHistorianProvisioning` `EnsureTags`
  hook for added historized tags.

The gateway API key must carry the scopes `historian:read`, `historian:write`, `historian:tags:write`.

## Where to read now

- **[../Historian.md](../Historian.md)** — the full historian guide (read path, alarm path, continuous
  historization, config keys, migration note).
- **[README.md](README.md)** — driver / back-end overview.
- **[../ServiceHosting.md](../ServiceHosting.md)** — deployment (the historian backend is the external
  HistorianGateway, not an installed sidecar).

## Migration

Deployments that carried the old `ServerHistorian` Wonderware keys must rename them:

| Old (Wonderware) key | New (gateway) key |
|---|---|
| `ServerHistorian:Host` + `:Port` | `ServerHistorian:Endpoint` (`https://host:5222`) |
| `ServerHistorian:SharedSecret` | `ServerHistorian:ApiKey` (supply via env `ServerHistorian__ApiKey`) |
| `ServerHistorian:ServerCertThumbprint` | `ServerHistorian:CaCertificatePath` (+ `UseTls` / `AllowUntrustedServerCertificate`) |

The `AlarmHistorian` section's old Wonderware connection keys (`Host`/`Port`/`UseTls`/`ServerCertThumbprint`/`SharedSecret`)
were pruned — remove them; the SQLite store-and-forward knobs are retained and the downstream connection is
now sourced from `ServerHistorian`.