Web API + Azure App Insights pass the data from ActionFilter to ITelemetryProcessor

Question

I'd like to customize my Application Insights logging behavior. So I'd like to set some sort of flag in my ActionFilter and then read that flag in ITelemetryProcessor.

public class MyCustomFilterAttribute: ActionFilterAttribute
{
    public override void OnActionExecuting(HttpActionContext filterContext)
    {
        //perform some logic and set the flag here
    }
}

and then

public class TelemetryFilter : ITelemetryProcessor
{
    public void Process(ITelemetry item)
    {
        var request = item as RequestTelemetry;
        //read the flag here and terminate processing
    }
}

Is that possible ? Is there some sort of TempData that's shared between those two types ? I'd like to avoid kind of hacks like setting temporary header and so on. Thanks in advance.

score 3 · Accepted Answer · answered Jul 09 '18 at 08:00

3

I'm not sure this will be useful. But I hope will be.

Using Activity.Current

    public void Initialize(ITelemetry telemetry)
    {
        Activity current = Activity.Current;

        if (current == null)
        {
            current = (Activity)HttpContext.Current?.Items["__AspnetActivity__"];
//put your code here
        }
}

Refer this SO

answered Jul 09 '18 at 08:00

Jayendran

9,638
8
60
103

1

yes it could be a solution, thank you. I was wondering if there is something built-in in Azure AI but `HttpContext.Current` can solve this problem – mickl Jul 09 '18 at 08:22

cijothomas · Answer 2 · 2018-07-09T23:26:51.427

Write a TelemetryInitializer where you have access to HttpContext.

//TelemetryInitializer

public void Initialize(ITelemetry telemetry)
    {
     var ctx = HttpContext.Current; // Telemetry Initialzer runs in same thread as the request.
     var request = item as RequestTelemetry;
     req.Properties.Add("MyActionFilter", "MyActionFilterValue")
     ...
    }

//TelemetryProcessor

public void Process(ITelemetry item)
    {
        var request = item as RequestTelemetry;
        //read the flag here and terminate processing
        if(req.Properties["MyActionFilter"] == "somthing")
        {
        ...
        }
    }

https://learn.microsoft.com/en-us/azure/application-insights/app-insights-api-filtering-sampling#itelemetryprocessor-and-itelemetryinitializer

For Asp.Net Core, injecting IHttpContextAccessor to the TelemetryInitializer constructor can get you context, as done here: https://github.com/Microsoft/ApplicationInsights-aspnetcore/blob/develop/src/Microsoft.ApplicationInsights.AspNetCore/TelemetryInitializers/TelemetryInitializerBase.cs

Thanks, it looks like something I'm looking for. The thing is that I'm not using .NET Core and currently installed NuGet package ( `version="2.4.0" targetFramework="net452"`) is not able to recognize `IHttpContextAccessor` is it something .NET Core specific ? — mickl, Jul 09 '18 at 07:37
For regular (non .net core) you can access `HttpContext.Current`, from a `TelemetryInitializer` as they are run in the same thread as the request. You can inspect the context and set some properties on the Telemetry from the initializer. And later use a `TelemetryProcessor` to take action based on the property set by Initializer. — cijothomas, Jul 09 '18 at 23:18

Web API + Azure App Insights pass the data from ActionFilter to ITelemetryProcessor

2 Answers2