How to exclude specific Trace from getting sampled out in AppInsights using in .net 6,7

[inishantmishra]

Our Log messages either, Info, Warning, or Error sometimes get sampled out. That's okay, but some logs are very important and we don't wanna lose them. I read multiple articles to use TelemeteryProcessor or TelemeteryInitizlizers but it doesn't help.

I want some of my logs which are important, those logs should never get sampled out. When I implemented the telemetry processors and initializers I found that these logs are now even getting more sampled out as compared to other logs.

Please help how to do that.

Here is the repo link. https://github.com/inishantmishra/TestAzureDotnetIsolatedFunction/tree/master I have an Azure Function- LoggingPOCFunction which has 3 logging. 1 should get Sample with whatever logic exists for adaptive sampling and 2 logging should never be sampled.

I created an extension method that uses those 2 Loggings. Kindly review and let me know what am i missing it here?

@kshyju @aishwaryabh @brettsam

[inishantmishra]

Can I get any reply here? @brettsam @kshyju

[RohitRanjanMS]

@inishantmishra You can add an ITelemetryProcessor to set the ProactiveSamplingDecision. https://github.com/RohitRanjanMS/ApplicationInsightsDemo/blob/main/InProcApplicationInsightsDemo/Startup.cs

using InProcApplicationInsightsDemo;
using Microsoft.ApplicationInsights.Channel;
using Microsoft.ApplicationInsights.DataContracts;
using Microsoft.ApplicationInsights.Extensibility;
using Microsoft.Azure.Functions.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection;
using System;

[assembly: FunctionsStartup(typeof(Startup))] 
namespace InProcApplicationInsightsDemo
{
    internal class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            builder.Services.AddSingleton<ITelemetryModule, MyModule>();
        }
    }

    internal class MyModule : ITelemetryModule
    {
        public void Initialize(TelemetryConfiguration configuration)
        {
            configuration.TelemetryProcessorChainBuilder.Use(next => new SamplingProcessor(next));
        }
    }

    internal class SamplingProcessor : ITelemetryProcessor
    {
        private readonly ITelemetryProcessor _next;

        public SamplingProcessor(ITelemetryProcessor next)
        {
            _next = next;
        }

        public void Process(ITelemetry item)
        {
            if (item is ISupportProperties propItem)
            {
                propItem.Properties["Processor"] = "SamplingProcessor";
            }

            // Ensure this is logged always
            if (item is TraceTelemetry trace && trace.Message.Contains("Important:"))
            {
                trace.ProactiveSamplingDecision = SamplingDecision.SampledIn;
            }
            _next.Process(item);
        }
    }
}

[inishantmishra]

@RohitRanjanMS What does SampledIn here indicates for samplingdecision? Will it be ignored???

I tried with this my logs are getting ignored. But when I used SampledOut i am getting logs. Please let me know what is correct?

[RohitRanjanMS]

SampledIn means the record would be retained and ingested. You can try running my sample code to check the behavior.