feat(sitestream): validate live-alarm-cache options + active-aggregator/reconnect telemetry (plan #10 T6)

Extend CommunicationOptionsValidator with eager bounds for the four T4 live-alarm-cache options (linger >= 0, reconcile > 0, seed concurrency 1..64, subscribers-per-site >= 1). Enforce the per-site viewer cap fail-safe in SiteAlarmLiveCacheService.Subscribe (reject excess viewers with a no-op disposable rather than growing the list or throwing into the Blazor render path). Surface two telemetry instruments on the existing ScadaBridgeTelemetry meter: an active-aggregator observable gauge and a reconnect counter, wired from the aggregator actor's PreStart/PostStop and its NodeA<->NodeB flip / reconcile-driven reopen. Claude-Session: https://claude.ai/code/session_01MtdgwpEeCUn6cUA5f1LMPj
2026-07-10 12:33:40 -04:00
parent b91ed3c840
commit c4f97d0e87
8 changed files with 263 additions and 5 deletions
@@ -0,0 +1,94 @@
+using System.Diagnostics.Metrics;
+using ZB.MOM.WW.ScadaBridge.Commons.Observability;
+
+namespace ZB.MOM.WW.ScadaBridge.Communication.Tests;
+
+/// <summary>
+/// Telemetry guards for the aggregated live alarm cache (plan #10, Task 6): the
+/// active-aggregator observable gauge reflects Started/Stopped, and the reconnect
+/// counter increments on each recorded reconnect. Mirrors the MeterListener read
+/// pattern used by <c>SiteStreamGrpcServerTests.SiteConnectionUpGauge_*</c>; reads are
+/// relative to a baseline so the process-wide static instruments are robust to any
+/// parallel test interleaving.
+/// </summary>
+public class SiteAlarmLiveCacheTelemetryTests
+{
+    private static long ReadGauge(string instrumentName)
+    {
+        long observed = 0;
+        using var listener = new MeterListener();
+        listener.InstrumentPublished = (instrument, l) =>
+        {
+            if (instrument.Meter.Name == ScadaBridgeTelemetry.MeterName &&
+                instrument.Name == instrumentName)
+            {
+                l.EnableMeasurementEvents(instrument);
+            }
+        };
+        listener.SetMeasurementEventCallback<long>((_, measurement, _, _) => observed = measurement);
+        listener.Start();
+        listener.RecordObservableInstruments();
+        return observed;
+    }
+
+    private static long ReadCounter(string instrumentName, Action act)
+    {
+        long delta = 0;
+        using var listener = new MeterListener();
+        listener.InstrumentPublished = (instrument, l) =>
+        {
+            if (instrument.Meter.Name == ScadaBridgeTelemetry.MeterName &&
+                instrument.Name == instrumentName)
+            {
+                l.EnableMeasurementEvents(instrument);
+            }
+        };
+        listener.SetMeasurementEventCallback<long>((_, measurement, _, _) => delta += measurement);
+        listener.Start();
+        act();
+        return delta;
+    }
+
+    [Fact]
+    public void ActiveAggregatorGauge_ReflectsStartAndStop()
+    {
+        const string gauge = "scadabridge.site.alarm_cache.aggregators.active";
+        var baseline = ReadGauge(gauge);
+
+        ScadaBridgeTelemetry.LiveAlarmAggregatorStarted();
+        try
+        {
+            Assert.Equal(baseline + 1, ReadGauge(gauge));
+
+            ScadaBridgeTelemetry.LiveAlarmAggregatorStarted();
+            try
+            {
+                Assert.Equal(baseline + 2, ReadGauge(gauge));
+            }
+            finally
+            {
+                ScadaBridgeTelemetry.LiveAlarmAggregatorStopped();
+            }
+
+            Assert.Equal(baseline + 1, ReadGauge(gauge));
+        }
+        finally
+        {
+            ScadaBridgeTelemetry.LiveAlarmAggregatorStopped();
+        }
+
+        Assert.Equal(baseline, ReadGauge(gauge));
+    }
+
+    [Fact]
+    public void ReconnectCounter_IncrementsOnEachRecordedReconnect()
+    {
+        var delta = ReadCounter("scadabridge.site.alarm_cache.reconnects", () =>
+        {
+            ScadaBridgeTelemetry.RecordLiveAlarmStreamReconnect();
+            ScadaBridgeTelemetry.RecordLiveAlarmStreamReconnect();
+        });
+
+        Assert.Equal(2, delta);
+    }
+}