Disable application insights in debug

Question

You can try to use TelemetryConfiguration.DisableTelemetry Property Something like this way..

#if DEBUG
            TelemetryConfiguration.Active.DisableTelemetry = true;
#endif

As an addition to the other solutions I would suggest to add the following let's say to the Global.asax:

protected void Application_Start()
{    
    DisableApplicationInsightsOnDebug();
    // do the other stuff
}

/// <summary>
/// Disables the application insights locally.
/// </summary>
[Conditional("DEBUG")]
private static void DisableApplicationInsightsOnDebug()
{
    TelemetryConfiguration.Active.DisableTelemetry = true;
}

The advantage of this is, that it needs no change to the configs and it works better with some tools like ReSharper which will understand it better than #-directives.

For ASP.NET Core projects the App Insights are ON by default, which actually logs a ton of info into debug window.

To disable it go to "TOOLS --> Options --> Projects and Solutions --> Web Projects" and check "Disable local Application Insights for Asp.Net Core web projects."

Below is the image for disabling local app insights.

For more info on the issue you can see the official github issue here

As explained in the question not deploying or deploying an ApplicationInsights.config without <instrumentationkey>key</instrumentationkey> block events from being generated. You can then put the instrumentation key in code (only on release in my case)

#if !DEBUG
    Microsoft.ApplicationInsights.Extensibility.TelemetryConfiguration.Active.InstrumentationKey = "instrumentation key";
#endif

Every TelemetryClient created after this call will have the correct key and will track events so you don't have to change the code in all places. Not calling the method above or leaving the parameter empty will block events because there isn't a key configured.

Basically the ApplicationInsights.config file overrides any code that set the instrumentation key, removing the <instrumentationkey>key</instrumentationkey> inside it will let you use code to configure the key. If you remove the file completely it doesn't work.

Here is the confirm: "If you want to set the key dynamically - for example if you want to send results from your application to different resources - you can omit the key from the configuration file, and set it in code instead."

Reference: https://azure.microsoft.com/en-us/documentation/articles/app-insights-configuration-with-applicationinsights-config/#_instrumentationkey

Running an ASP.NET Core 2.1 web application with Visual Studio 2017 (15.9.2) the "Disable local Application Insights for Asp.Net Core web projects" did not clear up the output in my Debug window.

However adding the following to Configure() in Startup.cs did the job;

if (_env.IsDevelopment())
{
    app.UseDeveloperExceptionPage();
    TelemetryConfiguration.Active.DisableTelemetry = true;
    TelemetryDebugWriter.IsTracingDisabled = true;
}

Note that the IsTracingDisabled was the key solution, but I left in DisableTelemetry for good measure! Plus having both lines next to one another is helpful when searching for similar references between .NET Framework & .NET Core projects in the same solution.

I have decided to use both approaches. I have moved the InstrumentationKey to the Web.config and it will be replaced by the transformation from Web.Release.config or Web.Debug.config. (don't forget to remove it from the ApplicationInsights.config file). Then I have called this method from the Application_Start()

public static void RegisterTelemetryInstrumentationKey()
{
    if (string.IsNullOrWhiteSpace(WebConfigurationManager.AppSettings["TelemetryInstrumentationKey"])
    {
        TelemetryConfiguration.Active.DisableTelemetry = true;
    }
    else
    {
        TelemetryConfiguration.Active.InstrumentationKey = AppSettings.TelemetryInstrumentationKey;
    }
}

As of ASP.NET Core 3.1:

• To disable logging any App Insights telemetry to Azure:

public void Configure(IApplicationBuilder app, IHostingEnvironment env,
    TelemetryConfiguration configuration)
{
    configuration.DisableTelemetry = true;
}

• To disable logging telemetry events to the Output window:

TelemetryDebugWriter.IsTracingDisabled = true;

(the above can be called from anywhere, but the sooner in your application's lifecycle, the better).

Both can be used together to suppress all Application Insights activity in your code. I guard with an #if DEBUG directive to ensure that AppInsights does nothing on my local machine, but does emit events when published to our dev server in the Azure cloud:

public void Configure(IApplicationBuilder app, IHostingEnvironment env,
    TelemetryConfiguration configuration)
{
    if (env.IsDevelopment())
    {
#if DEBUG
        configuration.DisableTelemetry = true;

        TelemetryDebugWriter.IsTracingDisabled = true;
#endif
    }
}