Failing dependency call in Azure Durable Functions

Question

Backgound

I have a set of Durable Azure Functions and they are written using the Async pattern, as described here.

Problem

After studying the logs in app insights I have spotted a recurring failure across all my functions.

It's a GET call to the DurableFunctionsHubInstances table. The below call results in a 404 response.

https://mydomain.table.core.windows.net:443/DurableFunctionsHubInstances(PartitionKey='f6eb7829ab6f4020af0431ab0115164a',RowKey='')?$select=ExecutionId,Name,Version,Output,CustomStatus,CreatedTime,LastUpdatedTime,RuntimeStatus,PartitionKey,RowKey,Timestamp,ETag

Question

Is this dependency failure normal? I'm guessing it is probably an initial call to the log table to check if there is a pre-existing instance that is needs to pick up and continue.

However I don't know this for a fact and would love to have this cleared up.

Screenshots

Lineup

I believe that's how table.CreateIfNotExists() actually works (Azure Storage SDK), (it asks the Storage API for the table and makes the POST request to create it if 404). – Septate

Answer 1

This does look like a normal dependency failure caused by the Azure Storage SDK checking for a pre-existing instance of a table. I've opened an issue in our GitHub repo to track suppressing dependency tracking of expected failed internal storage calls like this.

Counterpoint