Is it possible to set a "Delivery Header" in an Event Subscription to extract part of a dynamic header source field?

Question

Hi there,

I have an Event Subscription set up on an Event Grid Namespace Topic, with an Event Hub endpoint type. I want to create a header called PartitionKey with a value that's part of the topic name. My devices have different IDs and send various message types using the following topic scheme:

devices/<device_id>/<message_type>

What I want to do is set the PartitionKey as <device_id> to ensure message ordering for a specific device. However, I don't want to use another service. I was wondering, is it possible to set a "Delivery Header" in an Event Subscription to extract part of a dynamic header source field like this? If it's not possible to do this without another service, what is the best way to implement this in a way that is impossible to miss a single message processing?

Thank you.

Answer 1

Well, it seems that it is impossible without consuming data by an Azure function.