feat(historian-gateway): IHistorianProvisioning + GatewayTagProvisioner (EnsureTags, non-blocking)

Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii
2026-06-26 17:30:03 -04:00
parent d3081a659f
commit 8559905e8a
3 changed files with 268 additions and 0 deletions
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+namespace ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+/// <summary>
+///     Server-side historian tag provisioning — ensures the historian knows about the tags the
+///     address space historizes before values are written. Registered alongside
+///     <see cref="IHistorianDataSource"/> and invoked by the address-space applier when historized
+///     nodes are (re)applied.
+/// </summary>
+/// <remarks>
+///     Provisioning is best-effort and <b>non-blocking</b>: an unreachable or erroring historian
+///     never fails an address-space apply. Implementations return a
+///     <see cref="HistorianProvisionResult"/> tally instead of throwing, so the applier can surface
+///     a count without taking the server down. Non-historizable types are skipped (counted in
+///     <see cref="HistorianProvisionResult.Skipped"/>), not failed.
+/// </remarks>
+public interface IHistorianProvisioning
+{
+    /// <summary>
+    ///     Ensures the supplied historian tags exist (create-or-update). Never throws; a transport or
+    ///     backend failure is reported via <see cref="HistorianProvisionResult.Failed"/>.
+    /// </summary>
+    /// <param name="requests">The tags to ensure, with their driver data type and optional metadata.</param>
+    /// <param name="ct">A cancellation token for the operation.</param>
+    /// <returns>A tally of how the requests were handled.</returns>
+    Task<HistorianProvisionResult> EnsureTagsAsync(
+        IReadOnlyList<HistorianTagProvisionRequest> requests, CancellationToken ct);
+}
+
+/// <summary>
+///     A single historian tag to ensure — the driver-agnostic shape the applier hands to
+///     <see cref="IHistorianProvisioning.EnsureTagsAsync"/>. A backend maps
+///     <see cref="DataType"/> onto its native tag type and skips types it cannot historize.
+/// </summary>
+/// <param name="TagName">The full reference / tag name to ensure in the historian.</param>
+/// <param name="DataType">The driver-agnostic data type, used to select the historian tag type.</param>
+/// <param name="EngineeringUnit">Optional engineering unit (e.g. <c>degC</c>); <c>null</c> when unknown.</param>
+/// <param name="Description">Optional human-readable description; <c>null</c> when unknown.</param>
+public sealed record HistorianTagProvisionRequest(
+    string TagName,
+    DriverDataType DataType,
+    string? EngineeringUnit,
+    string? Description);
+
+/// <summary>
+///     The tally returned by <see cref="IHistorianProvisioning.EnsureTagsAsync"/>. The buckets
+///     partition the input: <c>Requested == Ensured + Skipped + Failed</c>.
+/// </summary>
+/// <param name="Requested">Total tags submitted.</param>
+/// <param name="Ensured">Tags the historian acknowledged as created or already present.</param>
+/// <param name="Skipped">Tags whose data type is not historizable on the backend (never sent).</param>
+/// <param name="Failed">Tags that were sent but the backend did not acknowledge (incl. a swallowed transport error).</param>
+public sealed record HistorianProvisionResult(
+    int Requested,
+    int Ensured,
+    int Skipped,
+    int Failed);
+
+/// <summary>
+///     No-op <see cref="IHistorianProvisioning"/> — the applier's safe default when no historian
+///     backend is registered. Every call returns an all-zero tally and never touches a backend.
+/// </summary>
+public sealed class NullHistorianProvisioning : IHistorianProvisioning
+{
+    /// <summary>The shared singleton instance.</summary>
+    public static readonly NullHistorianProvisioning Instance = new();
+
+    private NullHistorianProvisioning() { }
+
+    /// <inheritdoc />
+    public Task<HistorianProvisionResult> EnsureTagsAsync(
+        IReadOnlyList<HistorianTagProvisionRequest> requests, CancellationToken ct) =>
+        Task.FromResult(new HistorianProvisionResult(0, 0, 0, 0));
+}