feat(site-runtime): script scheduler gauges — queue depth, busy threads, oldest-busy age (S2/UA5)

2026-07-08 23:35:09 -04:00
parent b83d1ed19c
commit 474ec8a221
2 changed files with 85 additions and 3 deletions
@@ -44,4 +44,34 @@ public class ScriptExecutionSchedulerTests
        var b = ScriptExecutionScheduler.Shared(options);
        Assert.Same(a, b);
    }
+
+    // SiteRuntime-S2/UA5: the scheduler exposes observability gauges so a stuck /
+    // saturated script-execution pool is visible to operators via site health.
+    [Fact]
+    public async Task Gauges_ReflectBusyThreadAndQueueDepth()
+    {
+        using var scheduler = new ScriptExecutionScheduler(1);
+        using var gate = new ManualResetEventSlim(false);
+
+        var blocking = Task.Factory.StartNew(() => gate.Wait(),
+            CancellationToken.None, TaskCreationOptions.None, scheduler);
+        var queued = Task.Factory.StartNew(() => { },
+            CancellationToken.None, TaskCreationOptions.None, scheduler);
+
+        await WaitUntilAsync(() => scheduler.BusyThreadCount == 1);
+        Assert.Equal(1, scheduler.QueueDepth);          // second task waiting
+        Assert.True(scheduler.OldestBusyAge > TimeSpan.Zero);
+
+        gate.Set();
+        await Task.WhenAll(blocking, queued);
+        await WaitUntilAsync(() => scheduler.BusyThreadCount == 0);
+        Assert.Null(scheduler.OldestBusyAge);
+    }
+
+    private static async Task WaitUntilAsync(Func<bool> condition)
+    {
+        for (var i = 0; i < 100 && !condition(); i++)
+            await Task.Delay(50);
+        Assert.True(condition(), "condition not met within timeout");
+    }
 }