Implementing Application Insight to Azure Function App - azure

Question

Anyone know of any god guide for this?
First i created an Application Insight Resource and put:
APPINSIGHTS_INSTRUMENTATIONKEY = "INSTRUMENTATION KEY"
in the Function Apps Application Settings.
I have tried implementering the nuget package for the funtion app like this.
Createing a project.json file and pasting this:
{
"frameworks": {
"net46":{
"dependencies": {
"Microsoft.ApplicationInsights": "2.1.0"
}
}
}
}
It installed the nuget package (i could see it in the log, everything went well).
After that i put these snippets in my code to use the telemetry.TrackException(exception) functionality:
First...
using Microsoft.ApplicationInsights;
using Microsoft.ApplicationInsights.Extensibility;
Then:
var telemetry = new TelemetryClient(new TelemetryConfiguration("INSTRUMENTATION KEY"));
and in my catch:
telemetry.TrackException(e);
and when i try to save my Function app i get this error:
error CS1729: 'TelemetryConfiguration' does not contain a constructor that takes 1 arguments

Answer 1

You don't need to use reference the Application Insights library to use it with Functions. If you've already set the APPINSIGHTS_INSTRUMENTATIONKEY application setting, you can simply add the ILogger interface as a parameter to your function and it will automatically send the log data to your Application Insights instance.
Full documentation can be found here: https://learn.microsoft.com/en-us/azure/azure-functions/functions-monitoring

Answer 2

Addition to #ChrisGillum answer for .Net Core 3.1 Azure Function:
If you create a new Azure Function with Http trigger from Visual Studio the following line will exist in the example:
log.LogInformation("C# HTTP trigger function processed a request.");
Add "APPINSIGHTS_INSTRUMENTATIONKEY" to local.settings.json Values.
{
"IsEncrypted": false,
"Values": {
"AzureWebJobsStorage": "UseDevelopmentStorage=true",
"FUNCTIONS_WORKER_RUNTIME": "dotnet",
"APPINSIGHTS_INSTRUMENTATIONKEY": "<YOUR_GUID>"
},
}
Note that the key must be in an app setting named APPINSIGHTS_INSTRUMENTATIONKEY and nothing else.
Logging is then added automatically:
Complete guide for hosted values:
https://learn.microsoft.com/en-us/azure/azure-functions/functions-monitoring?tabs=cmd#enable-application-insights-integration