After making the suggested upgrade to .NET 8 and isolated worker functions, my blob storage event grid webhook no longer fires.
You need to add new querystring parameters to your storage account event webhook subscription to authenticate properly:
?functionName=Host.Functions.YourFunctionName
&code=zzzzzzzxxxxxxxxyyyyyyyyyyyyyy==
You need to add the name of your function in the format “Host.Functions.YourFunctionName“.
You need to add the blob extension key (code) which can be found in the Azure Portal for your function, under App Keys, called blobs_extension.
So the webhook should look something like this: https://<FUNCTION_APP_NAME>.azurewebsites.net/runtime/webhooks/blobs?functionName=Host.Functions.BlobTriggerEventGrid&code=<BLOB_EXTENSION_KEY>
Full reference can be found here: https://learn.microsoft.com/en-us/azure/azure-functions/functions-event-grid-blob-trigger?pivots=programming-language-csharp#build-the-endpoint-url