manual correlation in ASP.NET MVC apps

Jan 5, 2017 · 2 min read

I already wrote that correlation is not working well in ASP.NET MVC applications. Here is how you can fix it manually.

Assuming you are using Microsoft.ApplicationInsights.Web nuget package - you will have access to the RequestTelemetry stored in HttpContext.Current. You can store it in AsyncLocal (for FW 4.5 you can use CallContext) so it will ba available for all telemetry - sync and async run inside the action.

This is an example implementation that uses the same class as Action Filter and Telemetry Initializer.

namespace ApmTips
{
    public class ApplicationInsightsCorrelationActionFilter : ActionFilterAttribute, ITelemetryInitializer
    {
        private static AsyncLocal<RequestTelemetry> currentRequestTelemetry = new AsyncLocal<RequestTelemetry>();

        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            var request = HttpContext.Current.GetRequestTelemetry();
            currentRequestTelemetry.Value = request;

            base.OnActionExecuting(filterContext);
        }

        public override void OnActionExecuted(ActionExecutedContext filterContext)
        {
            currentRequestTelemetry.Value = null;

            base.OnActionExecuted(filterContext);
        }

        public override void OnResultExecuting(ResultExecutingContext filterContext)
        {
            var request = HttpContext.Current.GetRequestTelemetry();
            currentRequestTelemetry.Value = request;

            base.OnResultExecuting(filterContext);
        }

        public override void OnResultExecuted(ResultExecutedContext filterContext)
        {
            currentRequestTelemetry.Value = null;

            base.OnResultExecuted(filterContext);
        }

        public void Initialize(ITelemetry telemetry)
        {
            var request = currentRequestTelemetry.Value;

            if (request == null)
                return;

            if (string.IsNullOrEmpty(telemetry.Context.Operation.Id) && !string.IsNullOrEmpty(request.Context.Operation.Id))
            {
                telemetry.Context.Operation.Id = request.Context.Operation.Id;
            }

            if (string.IsNullOrEmpty(telemetry.Context.Operation.ParentId) && !string.IsNullOrEmpty(request.Id))
            {
                telemetry.Context.Operation.ParentId = request.Id;
            }

            if (string.IsNullOrEmpty(telemetry.Context.Operation.Name) && !string.IsNullOrEmpty(request.Name))
            {
                telemetry.Context.Operation.Name = request.Name;
            }

            if (string.IsNullOrEmpty(telemetry.Context.User.Id) && !string.IsNullOrEmpty(request.Context.User.Id))
            {
                telemetry.Context.User.Id = request.Context.User.Id;
            }

            if (string.IsNullOrEmpty(telemetry.Context.Session.Id) && !string.IsNullOrEmpty(request.Context.Session.Id))
            {
                telemetry.Context.Session.Id = request.Context.Session.Id;
            }
        }
    }
}

Here is how you’d register it in Global.asax.cs:

var filter = new ApplicationInsightsCorrelationActionFilter();
GlobalFilters.Filters.Add(filter);
TelemetryConfiguration.Active.TelemetryInitializers.Add(filter);

You can always use one of community-supported MVC monitoring NuGets which will be doing a similar things to enable this correlation.

manual correlation in ASP.NET MVC apps

Comments