Appinsights Instrumentation

Auto-instrument app

Use Azure Portal to auto-instrument a webapp hosted in Azure App Service for App Insights without making any code changes. Only the following types of app can be auto-instrumented. See supported environments and resource providers.

• ASP.NET Core app hosted in Azure App Service
• Node.js app hosted in Azure App Service

Construct a url to bring the user to the Application Insights blade in Azure Portal for the App Service App.

https://portal.azure.com/#resource/subscriptions/{subscription_id}/resourceGroups/{resource_group_name}/providers/Microsoft.Web/sites/{app_service_name}/monitoringSettings

Use the context or ask the user to get the subscription_id, resource_group_name, and the app_service_name hosting the webapp.

Modify code

Make these necessary changes to the app.

• Install client library

dotnet add package Azure.Monitor.OpenTelemetry.AspNetCore

• Configure the app to use Azure Monitor

An ASP.NET Core app typically has a Program.cs file that "builds" the app. Find this file and apply these changes.

• Add using Azure.Monitor.OpenTelemetry.AspNetCore; at the top
• Before calling builder.Build(), add this line builder.Services.AddOpenTelemetry().UseAzureMonitor();.

Note: since we modified the code of the app, the app needs to be deployed to take effect.

Configure App Insights connection string

The App Insights resource has a connection string. Add the connection string as an environment variable of the running app. You can use Azure CLI to query the connection string of the App Insights resource. See scripts/appinsights.ps1 for what Azure CLI command to execute for querying the connection string.

After getting the connection string, set this environment variable with its value.

"APPLICATIONINSIGHTS_CONNECTION_STRING={your_application_insights_connection_string}"

If the app has IaC template such as Bicep or terraform files representing its cloud instance, this environment variable should be added to the IaC template to be applied in each deployment. Otherwise, use Azure CLI to manually apply the environment variable to the cloud instance of the app. See scripts/appinsights.ps1 for what Azure CLI command to execute for setting this environment variable.

Important: Don't modify appsettings.json. It was a deprecated way to configure App Insights. The environment variable is the new recommended way.

MIT License

Copyright 2025 (c) Microsoft Corporation.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE

Modify code

Make these necessary changes to the app.

• Install client library

npm install @azure/monitor-opentelemetry

• Configure the app to use Azure Monitor

A Node.js app typically has an entry file that is listed as the "main" property in package.json. Find this file and apply these change