Added 502.3 response for timed out requests and logging for requests exceeding timeout threshold.

Author: rhamlett_microsoft

src/PerfProblemSimulator/Controllers/AdminController.cs

@@ -1,3 +1,4 @@
+using Microsoft.AspNetCore.Http.Timeouts;
 using Microsoft.AspNetCore.Mvc;
 using PerfProblemSimulator.Models;
 using PerfProblemSimulator.Services;
@@ -25,6 +26,7 @@ namespace PerfProblemSimulator.Controllers;
 /// </remarks>
 [ApiController]
 [Route("api/[controller]")]
+[RequestTimeout("NoTimeout")] // Admin endpoints must always respond
 public class AdminController : ControllerBase
 {
     private readonly ISimulationTracker _simulationTracker;

src/PerfProblemSimulator/Controllers/HealthController.cs

@@ -1,3 +1,4 @@
+using Microsoft.AspNetCore.Http.Timeouts;
 using Microsoft.AspNetCore.Mvc;
 using PerfProblemSimulator.Services;
 
@@ -23,6 +24,7 @@ namespace PerfProblemSimulator.Controllers;
 [ApiController]
 [Route("api/[controller]")]
 [Produces("application/json")]
+[RequestTimeout("NoTimeout")] // Health endpoints must always respond, never timeout
 public class HealthController : ControllerBase
 {
     private readonly ISimulationTracker _simulationTracker;

src/PerfProblemSimulator/Controllers/MetricsController.cs

@@ -1,3 +1,4 @@
+using Microsoft.AspNetCore.Http.Timeouts;
 using Microsoft.AspNetCore.Mvc;
 using PerfProblemSimulator.Models;
 using PerfProblemSimulator.Services;
@@ -25,6 +26,7 @@ namespace PerfProblemSimulator.Controllers;
 /// </remarks>
 [ApiController]
 [Route("api/[controller]")]
+[RequestTimeout("NoTimeout")] // Metrics endpoints must always respond
 public class MetricsController : ControllerBase
 {
     private readonly IMetricsCollector _metricsCollector;

src/PerfProblemSimulator/Controllers/SlowRequestController.cs

@@ -1,3 +1,4 @@
+using Microsoft.AspNetCore.Http.Timeouts;
 using Microsoft.AspNetCore.Mvc;
 using PerfProblemSimulator.Models;
 using PerfProblemSimulator.Services;
@@ -34,6 +35,7 @@ namespace PerfProblemSimulator.Controllers;
 [Route("api/[controller]")]
 [Produces("application/json")]
 [Tags("Slow Request Simulation")]
+[RequestTimeout("SlowRequest")] // Extended 120s timeout for intentionally slow requests
 public class SlowRequestController : ControllerBase
 {
     private readonly ISlowRequestService _slowRequestService;

src/PerfProblemSimulator/Program.cs

@@ -169,6 +169,37 @@
     });
 });
 
+// -----------------------------------------------------------------------------
+// Request Timeouts (Kestrel)
+// -----------------------------------------------------------------------------
+// Add request timeouts for local development to match IIS behavior (web.config).
+// This ensures slow requests timeout after 30 seconds, consistent with the UI threshold.
+// Educational Note: In Azure App Service, the web.config requestTimeout handles this.
+// For local Kestrel development, we use the RequestTimeouts middleware instead.
+builder.Services.AddRequestTimeouts(options =>
+{
+    // Default 30-second timeout for all endpoints (matches web.config and UI threshold)
+    options.DefaultPolicy = new Microsoft.AspNetCore.Http.Timeouts.RequestTimeoutPolicy
+    {
+        Timeout = TimeSpan.FromSeconds(30),
+        TimeoutStatusCode = StatusCodes.Status504GatewayTimeout
+    };
+    
+    // Extended timeout for slow request simulation endpoint
+    // This endpoint intentionally runs 20-35s requests, so it needs more time
+    options.AddPolicy("SlowRequest", new Microsoft.AspNetCore.Http.Timeouts.RequestTimeoutPolicy
+    {
+        Timeout = TimeSpan.FromSeconds(120),
+        TimeoutStatusCode = StatusCodes.Status504GatewayTimeout
+    });
+    
+    // No timeout for health/admin endpoints - they must always respond
+    options.AddPolicy("NoTimeout", new Microsoft.AspNetCore.Http.Timeouts.RequestTimeoutPolicy
+    {
+        Timeout = null // Disable timeout
+    });
+});
+
 var app = builder.Build();
 
 // -----------------------------------------------------------------------------
@@ -195,6 +226,10 @@
 // CORS must be called before UseRouting
 app.UseCors();
 
+// Request timeouts middleware (Kestrel) - matches web.config requestTimeout for IIS
+// Educational Note: This must be placed before UseRouting so timeouts apply to all requests.
+app.UseRequestTimeouts();
+
 // Serve static files from wwwroot (for the SPA dashboard)
 app.UseDefaultFiles(); // Enables default document (index.html)
 app.UseStaticFiles();

src/PerfProblemSimulator/web.config

@@ -10,6 +10,10 @@
         
         When hosting model is "outofprocess", the app runs in a separate dotnet.exe process,
         and Azure Crash Monitoring (which monitors w3wp.exe) won't capture crashes.
+        
+        requestTimeout="00:00:30" - 30 second timeout matches the UI threshold.
+        Requests exceeding this will fail with HTTP 502.3 (Bad Gateway - timeout).
+        This demonstrates realistic timeout behavior for educational purposes.
       -->
       <handlers>
         <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" />
@@ -18,7 +22,8 @@
                   arguments=".\PerfProblemSimulator.dll" 
                   stdoutLogEnabled="false" 
                   stdoutLogFile=".\logs\stdout" 
-                  hostingModel="inprocess">
+                  hostingModel="inprocess"
+                  requestTimeout="00:00:30">
         <environmentVariables>
           <!-- Enable detailed errors for diagnostics -->
           <environmentVariable name="ASPNETCORE_DETAILEDERRORS" value="true" />

src/PerfProblemSimulator/wwwroot/js/dashboard.js

@@ -558,6 +558,11 @@ function handleSlowRequestLatency(data) {
             msg += ` [Queue Time: ${queueSec}s]`;
         }
         logEvent('error', msg);
+    } else if (isTimeout) {
+        // Request completed but exceeded the 30s timeout threshold
+        // In IIS with requestTimeout="00:00:30", this would have been terminated with HTTP 502.3
+        let msg = `⏱️ Slow request #${data.requestNumber} TIMEOUT: ${durationSec}s exceeded 30s threshold (${scenario}) [Queue Time: ${queueSec}s]`;
+        logEvent('error', msg);
     } else {
         let msg = `🐌 Slow request #${data.requestNumber} completed: ${durationSec}s (${scenario}) [Queue Time: ${queueSec}s]`;
         logEvent('warning', msg);