Application Insights RequestTelemetry not showing up in Requests after exception

Question

I have spent a while trying to RequestTelemetry to work. It did when I was first playing around with it, but then oddly just stopped working whenever an exception is thrown. I have read documentation using Application Insights for custom events and metrics as well as Custom Operations Tracking and tried to add all of the best practices to see if I could get the result to show up again. I'm using .NET Core 3.1 and Microsoft.ApplicationInsights.AspNetCore 2.14.0.

Setup for the Webapp looks like this in Startup.cs

services.AddApplicationInsightsTelemetry(new ApplicationInsightsServiceOptions { 
    EnableAdaptiveSampling = false
}); 

I have the telemetry inside of a Controller Post Action. I realize that Application Insights is already tracking it the post action, but I wanted to see if I could track the inner method. This is the code in my controller:

public MyController(IMyService myService, TelemetryClient telemetryClient, ILogger<MyController> logger) {
    _myService = myService;
    _telemetryClient = telemetryClient;
    _logger = logger;
}

[HttpPost]
[ProducesResponseType(StatusCodes.Status204NoContent)]
[ProducesResponseType(StatusCodes.Status400BadRequest)]
[ProducesResponseType(StatusCodes.Status401Unauthorized)]
public async Task<IActionResult> PostAsync([FromBody] MyModel model) {
    using var scope = _logger.BeginScope(new Dictionary<string, object> {
        { $"{nameof(PostAsync)}.Scope", Guid.NewGuid() },
        { nameof(model.Name), model.Name }
    });

    model.AuthenticatedUserId = User.GetUserIdFromClaims();

    var requestTelemetry = new RequestTelemetry { Name = nameof( _myService.MyFunctionAsync) };
    var operation = _telemetryClient.StartOperation(requestTelemetry);
    operation.Telemetry.Properties.Add("User", model.AuthenticatedUserId);

    try {
        await _myService.MyFunctionAsync(model).ConfigureAwait(false); // <-- throws exception
        operation.Telemetry.Success = true;
        return NoContent();
    } catch (Exception e) {
        operation.Telemetry.Success = false;
        throw;
    } finally {
        _telemetryClient.StopOperation(operation);
    }
}

I can see in the Visual Studio console output that the code executes, as I get the following log, but it never shows up in the Application Insights Requests.

Application Insights Telemetry: {
  "name": "AppRequests",
  "time": "2020-06-21T14:29:08.7469588Z",
  "iKey": "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX",
  "tags": {
    "ai.application.ver": "1.0.0.0",
    "ai.cloud.roleInstance": "DESKTOP-K74PNCU",
    "ai.operation.id": "0443259d660125498cf28f8f7a275dab",
    "ai.operation.parentId": "1dea6f9b27220c4c",
    "ai.operation.name": "POST EventEmitter/Post",
    "ai.location.ip": "::1",
    "ai.internal.sdkVersion": "dotnetc:2.14.0-17971",
    "ai.internal.nodeName": "DESKTOP-K74PNCU"
  },
  "data": {
    "baseType": "RequestData",
    "baseData": {
      "ver": 2,
      "id": "2b7900eedfb7c34d",
      "name": "MyFunctionAsync",
      "duration": "00:00:00.3766937",
      "success": false,
      "properties": {
        "DeveloperMode": "true",
        "User": "pobl-dev",
        "_MS.ProcessedByMetricExtractors": "(Name:'Requests', Ver:'1.1')",
        "AspNetCoreEnvironment": "Development"
      }
    }
  }
}

Answer 1

There is a simple solution, but I'm not sure of why it's necessary, due to either a lack in documentation or a bug. I found once a responseCode was provided everything works fine. There is a default responseCode of 200 which shows up on a successful call. Once I set the value on a failure everything worked fine.

public MyController(IMyService myService, TelemetryClient telemetryClient, ILogger<MyController> logger) {
    _myService = myService;
    _telemetryClient = telemetryClient;
    _logger = logger;
}

[HttpPost]
[ProducesResponseType(StatusCodes.Status204NoContent)]
[ProducesResponseType(StatusCodes.Status400BadRequest)]
[ProducesResponseType(StatusCodes.Status401Unauthorized)]
public async Task<IActionResult> PostAsync([FromBody] MyModel model) {
    using var scope = _logger.BeginScope(new Dictionary<string, object> {
        { $"{nameof(PostAsync)}.Scope", Guid.NewGuid() },
        { nameof(model.Name), model.Name }
    });

    model.AuthenticatedUserId = User.GetUserIdFromClaims();

    var requestTelemetry = new RequestTelemetry { Name = nameof( _myService.MyFunctionAsync) };
    var operation = _telemetryClient.StartOperation(requestTelemetry);
    operation.Telemetry.Properties.Add("User", model.AuthenticatedUserId);

    try {
        await _myService.MyFunctionAsync(model).ConfigureAwait(false); // <-- throws exception
        operation.Telemetry.Success = true;
        operation.Telemetry.ResponseCode = "Roses";
        return NoContent();
    } catch (Exception e) {
        operation.Telemetry.Success = false;
        operation.Telemetry.ResponseCode = "Funky"; // <-- seems to be required on a failure
        throw;
    } finally {
        _telemetryClient.StopOperation(operation);
    }
}

Answer 2

This is to add some context to the accepted answer if you're curious:

Here's the source code for RequestTelemetry

When it prepares the data to send to Azure servers it explicitly elects NOT to set a default response code unless success == true in which case the default is 200.

// Required fields
if (!this.Success.HasValue)
{
    this.Success = true;
}

if (string.IsNullOrEmpty(this.ResponseCode))
{
    this.ResponseCode = this.Success.Value ? "200" : string.Empty;
}     

If you run a simple Kusto query on the logs:

union requests | where timestamp > ago(1hr) | where customDimensions["CustomOperationCategory"] in ("Identity") | take 100

You'll only see unsuccessful results where you did set a status code:

I don't know if something ever changed, but Microsoft's examples sometimes do the same.