Logging of function key for calls to Azure Function

Question

Hello,

I have an Azure Function that I configured with a number of function keys (API keys). This all works very well and allows access only to those users that provide the key I gave them.

Now I was trying to find out which of the keys was used for a specific call to my API, but wasn't able to find it in the logs. I've looked all over the internet but haven't found anything about this topic.

Could anybody point me to the location in the logs where I could identify which API key was used?

Thanks!

Answer 1

Hi @ak-3792

Welcome to Microsoft Q&A! Thanks for posting the question.

By default, this information will not be logged. You need to customize your code to log this information and in the Traces table of application insight, you can get this information.

    const string key_Claim = "http://schemas.microsoft.com/2017/07/functions/claims/keyid";  
    var claim = req.HttpContext.User.Claims.FirstOrDefault(c => c.Type == key_Claim);  
    if(claim != null)  
    {  
        log.LogInformation( "The call was made using {0} named key", claim.Value);  
    }  

In Application Insights:

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