Add Application Insights to an Existing ASP.NET Core Application

I have been using Azure’s App Service to host the web applications I am playing around with for a few years now. The service makes it simple to get an application hosted. Today I decided to try out Application Insights which is an application performance management (APM) service provided by Azure which integrates very well with App Service. In fact, you can enable Application Insights for your App Service Application without the need to make any code changes.

This post is going to cover using an existing App Service application and enabling Application Insights. This post is assuming that you already have an Azure account. If you don’t you can sign up for a free Azure account.

Sample Application and App Service Creation

In case you don’t have an existing application in Azure App Service here is a quick walkthrough of the application I used for this post. If you have an existing application you can skip to the next section.

From the .NET CLI I used the following command to create a global.json targeting .NET Core 2.2 in the directory the application is being created in. You don’t have to do this step, but I needed it because I have .NET Core 3 preview installed and I wanted this post to target the current production release of .NET Core.

dotnet new globaljson --sdk-version 2.2.105

Next, run the following command to create a new ASP.NET Core application using the React template. Any of the templates are fine so feel free to use a different one as long as it will give you a web application.

dotnet new react

Now open the new project in Visual Studio and right-click on the project file and click Publish.

Select App Service and then click Publish.

The next dialog is all about the setup of your App Service. I took the defaults for the most part, with the exception of the Resource Group which I made sure to create one just for this application to allow for easy clean up later. When you have all your options selected click Create. Note that there is an option to setup Application Insights from this screen, but we are going to handle this on the Azure side after the fact for this post.

After the deployment is done your application should open up in a browser.

Add Application Insights from the Azure Portal

Now that we have an application running in an Azure App Service we are ready to add in Application Insights. First head to the Azure Portal and select App Services from the menu.

From your list of App Services select the one you want to add Application Insights to. From the menu select Application Insights. In the details click the Turn on site extension button to update the Application Insights extension if needed.

On the next screen select the Location where you would like the Application Insights deployed. You can tweak what will be instrumented based on the language your application is built in, I just kept the defaults. When all your selections are done click Apply.

When you click apply, you will get a warning that your site will have to be restarted. For a test application, this isn’t a big deal, but if you are on a production application you might want to do this during a slow period. Click Yes to continue.

After the process is complete click the View Application Insights data link to view your Application Insights Overview.

The overview will give you a fast overview of how your application is doing with graphs of Failed request, Server response time, Server requests, and Availability.

Wrapping Up

Hopefully, this will help you get going with Application Insights. This post didn’t cover many of the features that Application Insights provides, but should get you set up so you can explore all the features the service provides.


Also published on Medium.

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