fix(kpi-history): backlogTotal trend records the real site-backlog aggregate instead of a hardwired zero

2026-07-09 07:51:55 -04:00
parent 1dd993ec2f
commit 1b53de1933
6 changed files with 271 additions and 3 deletions
@@ -0,0 +1,33 @@
+namespace ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Kpi;
+
+/// <summary>
+/// Supplies the system-wide pending Audit Log backlog for the
+/// <c>backlogTotal</c> KPI history sample ("KPI History &amp; Trends").
+/// </summary>
+/// <remarks>
+/// <para>
+/// The append-only Audit Log repository leaves <c>AuditLogKpiSnapshot.BacklogTotal</c>
+/// at zero — the backlog is not a central-table count but the sum of the latest
+/// per-site <c>SiteAuditBacklog.PendingCount</c> health reports, which live only in
+/// the in-memory central health aggregator. The live Health-dashboard "Audit" tile
+/// already fills this in (<c>AuditLogQueryService.GetKpiSnapshotAsync</c>); this seam
+/// lets the KPI <em>history</em> sample source read the same aggregate instead of
+/// persisting a hardwired zero.
+/// </para>
+/// <para>
+/// Best-effort: sites that have not yet reported (or whose reporter is disabled)
+/// contribute zero — a missing snapshot is treated as "unknown, count as nothing",
+/// mirroring the live tile. Central-only: registered on the central node where the
+/// health aggregator lives; sites and unit tests leave it unregistered so the
+/// sample source falls back to the snapshot's own <c>BacklogTotal</c>.
+/// </para>
+/// </remarks>
+public interface IAuditBacklogProvider
+{
+    /// <summary>
+    /// Returns the current total pending (not-yet-forwarded) Audit Log backlog,
+    /// summed across every site's latest health report. Never negative; zero when
+    /// no site is reporting a backlog.
+    /// </summary>
+    long GetPendingBacklogTotal();
+}