How to add custom data on exception handling using azure webjobs SDK? - azure

Question

I have a simple Azure Function which returns to a queue:
private readonly TelemetryClient _telemetryClient;
[return: Queue("%ReturnQueue%")]
public async Task<string> Run([QueueTrigger("%RequestQueue%")] string msg, ILogger log)
{
try
{
//Some dependency calls
}
catch(Exception ex)
{
var dic = new Dictionary<string,string>();
dic.Add("Id", someId);
dic.Add("CustomData", cusomData);
_telemetryClient.TrackException(ex, dic);
}
}
I obviously get a compilation error saying that not all code paths returns a value.
The problem is that if I add a throw at the end of the catch block the Azure Functions runtime replicate the excpetion on the appinsights portal. How can I add custom data to my exceptions like this?

Answer 1

You can create your own Exception type:
public class MyCustomException : Exception
{
public string Id {get;set;}
public string CustomData {get;set;}
public Exception RootException {get;set;}
public MyCustomException(string id, string customData, Exception ex)
{
Id = id;
CustomData = customData;
RootException = ex;
}
}
private readonly TelemetryClient _telemetryClient;
[return: Queue("%ReturnQueue%")]
public async Task<string> Run([QueueTrigger("%RequestQueue%")] string msg, ILogger log)
{
try
{
//Some dependency calls
}
catch(Exception ex)
{
//var dic = new Dictionary<string,string>();
//dic.Add("Id", someId);
//dic.Add("CustomData", cusomData);
var customEx = new MyCustomException(someId, cusomData, ex);
_telemetryClient.TrackException(customEx);
}
finally
{
return "";
}
}
PS: inside MyCustomException you can actually have Dictionary rather than string properties.