How do you configure an Event Hub KEDA scaler for Azure Container Apps?

Question

I’ve been trying to configure an Azure Container App to have a custom scale rule using the event-hub KEDA scaler, and I haven't had any success.

I always hit this error:

unable to get unprocessedEventCount for metrics: unable to get checkpoint from storage: %!w()

Unfortunately, the error doesn’t give much away about the problem it’s facing.

This is my scaler:

         {
            name: 'my-eh-keda-scaler'
            custom: {
              type: 'azure-eventhub'
              metadata: {
                connectionFromEnv: 'KEDA_EH_CONNECTION'
                storageConnectionFromEnv: 'KEDA_STORAGE_CONNECTION'
                consumerGroup: 'my-consumer-group'
                unprocessedEventThreshold: '64'
                blobContainer: 'my-container'
                checkpointStrategy: 'blobMetadata'
                activationUnprocessedEventThreshold: '1'
              }
            }
          }

The referenced connection string in the environment variable works and has full access. The event hub connection string also works and has full access.

I’ve followed the documentation here: Azure Event Hubs

How can I fix this or alternatively is there an example that works?