Filtering Exceptions in Application Insights

Oct 13, 2025 by talynt.org 38 views

Introduction

Azure Application Insights is a powerful tool for monitoring and analyzing the performance of web applications. It provides valuable insights into user behavior, application performance, and error tracking. However, with the increasing complexity of modern web applications, it's not uncommon to encounter a large number of exceptions in Application Insights, many of which may be irrelevant or caused by external factors. In this article, we'll explore how to filter exceptions sent to Application Insights from the client side, helping you to focus on the exceptions that matter most.

Understanding the Problem

When you encounter the error message "Script error: The browser's same-origin policy prevents us from..." in Azure Application Insights, it's likely due to a cross-origin request being made from your application. This can happen when your application makes a request to a different domain or protocol, triggering the browser's same-origin policy. As a result, the exception is reported in Application Insights, but it's not necessarily an error that you need to worry about.

Why Filter Exceptions?

Filtering exceptions in Application Insights is essential for several reasons:

Reduced noise: By filtering out irrelevant exceptions, you can reduce the noise in your Application Insights data, making it easier to focus on the exceptions that matter most.
Improved performance: Filtering exceptions can improve the performance of your application by reducing the number of unnecessary requests and computations.
Enhanced user experience: By filtering out exceptions that don't affect the user experience, you can provide a better experience for your users.

Filtering Exceptions in Application Insights

To filter exceptions in Application Insights, you can use the following methods:

1. Using the Application Insights SDK

You can use the Application Insights SDK to filter exceptions at the client-side. To do this, you need to create a custom exception filter that checks the exception type and message before sending it to Application Insights.

using Microsoft.ApplicationInsights;
using Microsoft.ApplicationInsights.DataContracts;
public class CustomExceptionFilter : IExceptionFilter
{
public bool IsEnabled { get; set; }
public bool ShouldSendException(Exception exception)
{
    // Check if the exception is a script error
    if (exception is ScriptError)
    {
        return false;
    }

    // Check if the exception message contains the phrase &quot;same-origin policy&quot;
    if (exception.Message.Contains(&quot;same-origin policy&quot;))
    {
        return false;
    }

    return true;
}

}

2. Using the Application Insights Configuration

You can also filter exceptions in Application Insights by configuring the Application Insights settings. To do this, you need to add a custom configuration section to your application settings.

{
  "ApplicationInsights": {
    "InstrumentationKey": "your_instrumentation_key",
    "ExceptionFilters": {
      "Enabled": true,
      "Filters": [
        {
          "Type": "ScriptError",
          "Enabled": false
        },
        {
          "Type": "SameOriginPolicy",
          "Enabled": false
        }
      ]
    }
  }
}

3. Using the Application Insights API

You can also filter exceptions in Application Insights using the Application Insights API. To do this, you need to create a custom API client that checks the exception type and message before sending it to Application Insights.

using Microsoft.ApplicationInsights;
using Microsoft.ApplicationInsights.DataContracts;
public class CustomApiClient : IApiClient
{
public bool ShouldSendException(Exception exception)
{
// Check if the exception is a script error
if (exception is ScriptError)
{
return false;
}
    // Check if the exception message contains the phrase &quot;same-origin policy&quot;
    if (exception.Message.Contains(&quot;same-origin policy&quot;))
    {
        return false;
    }

    return true;
}

}

Conclusion

Filtering exceptions sent to Application Insights from the client side is an essential step in reducing noise and improving performance. By using the Application Insights SDK, configuration, or API, you can create custom exception filters that check the exception type and message before sending it to Application Insights. This helps you to focus on the exceptions that matter most, providing a better experience for your users.

Best Practices

Here are some best practices to keep in mind when filtering exceptions in Application Insights:

Use a combination of filters: Use a combination of filters to catch different types of exceptions.
Use regular expressions: Use regular expressions to match exception messages.
Test your filters: Test your filters thoroughly to ensure they are working as expected.
Monitor your filters: Monitor your filters regularly to ensure they are not causing any issues.

Common Issues

Here are some common issues to watch out for when filtering exceptions in Application Insights:

Incorrect filter configuration: Make sure your filter configuration is correct and up-to-date.
Missing exception types: Make sure you are catching all the exception types you need to filter.
Incorrect exception message matching: Make sure you are matching the exception message correctly using regular expressions.

Future Development

In the future, we plan to enhance the Application Insights SDK and API to provide more advanced filtering capabilities. We also plan to provide more documentation and samples to help developers get started with filtering exceptions in Application Insights.

References

Here are some references to get you started with filtering exceptions in Application Insights:

Application Insights SDK: https://docs.microsoft.com/en-us/azure/azure-monitor/app/api-filtering-sampling
Application Insights Configuration: https://docs.microsoft.com/en-us/azure/azure-monitor/app/configuration
Application Insights API: https://docs.microsoft.com/en-us/azure/azure-monitor/app/api

Introduction

In our previous article, we discussed how to filter exceptions sent to Application Insights from the client side. We covered the importance of filtering exceptions, the different methods for filtering exceptions, and some best practices to keep in mind. In this article, we'll answer some frequently asked questions about filtering exceptions in Application Insights.

Q: Why do I need to filter exceptions in Application Insights?

A: Filtering exceptions in Application Insights is essential for several reasons:

Reduced noise: By filtering out irrelevant exceptions, you can reduce the noise in your Application Insights data, making it easier to focus on the exceptions that matter most.
Improved performance: Filtering exceptions can improve the performance of your application by reducing the number of unnecessary requests and computations.
Enhanced user experience: By filtering out exceptions that don't affect the user experience, you can provide a better experience for your users.

Q: How do I know which exceptions to filter?

A: To determine which exceptions to filter, you need to analyze your Application Insights data and identify the types of exceptions that are causing the most noise. You can use the Application Insights SDK, configuration, or API to filter exceptions based on their type, message, or other criteria.

Q: Can I use regular expressions to filter exceptions?

A: Yes, you can use regular expressions to filter exceptions in Application Insights. Regular expressions can help you match exception messages and filter out exceptions that don't match a specific pattern.

Q: How do I test my exception filters?

A: To test your exception filters, you can use the Application Insights SDK, configuration, or API to simulate exceptions and verify that your filters are working as expected.

Q: Can I use a combination of filters to catch different types of exceptions?

A: Yes, you can use a combination of filters to catch different types of exceptions. For example, you can use a filter to catch script errors and another filter to catch exceptions that contain a specific phrase.

Q: How do I monitor my exception filters?

A: To monitor your exception filters, you can use the Application Insights SDK, configuration, or API to track the number of exceptions that are being filtered and the types of exceptions that are being filtered.

Q: Can I use Application Insights to filter exceptions in real-time?

A: Yes, you can use Application Insights to filter exceptions in real-time. The Application Insights SDK, configuration, or API can be used to filter exceptions as they occur, reducing the noise in your Application Insights data.

Q: How do I troubleshoot issues with my exception filters?

A: To troubleshoot issues with your exception filters, you can use the Application Insights SDK, configuration, or API to track the number of exceptions that are being filtered and the types of exceptions that are being filtered. You can also use the Application Insights dashboard to view the exceptions that are being filtered and identify any issues with your filters.

Q: Can I use Application Insights to filter exceptions in a distributed environment?

A: Yes, you can use Application Insights to filter exceptions in a distributed environment. The Application Insights SDK, configuration, or API can be used to filter exceptions across multiple servers and applications, reducing the noise in your Application Insights data.