HttpContext and TelemetryInitializer

Question

I want to attach the user\'s \"client_id\" claim as a property to every request sent to Application Insights.

From what I\'ve read, I should be implementing IT

Answer 1

I wish this were designed into AppInsights but you can directly use the static HttpContext.Current. You can use it's per-request Items dictionary as a short term (near stateless) storage space to deliver your custom values to the custom telemetry handler.

So try

class AppInsightCustomProps : ITelemetryInitializer
{
    public void Initialize(ITelemetry telemetry)
    {
        var requestTelemetry = telemetry as RequestTelemetry;
        // Is this a TrackRequest() ?
        if (requestTelemetry == null) return;

        var httpCtx = HttpContext.Current;
        if (httpCtx != null)
        {
            var customPropVal = (string)httpCtx.Items["PerRequestMyCustomProp"];
            if (!string.IsNullOrWhiteSpace(customPropVal))
            {
                requestTelemetry.Properties["MyCustomProp"] = customPropVal;
            }
        }
    }
}

And to program the desired custom property, anywhere in your request pipeline have something like

if (HttpContext.Current != null)
{
    HttpContext.Current.Items["PerRequestMyCustomProp"] = myCustomPropValue;
}