A mallow-bend Function should run only for blobs under /orders, not for every blob in the storage account. How should Event Grid narrow delivery?
Select an answer to reveal the explanation.
Short Explanation
Specialize the handler with filters. Event type and subject (begins-with, and friends) keep /orders events on this Function and leave the rest alone.
Full Explanation
Event Grid subscriptions can filter by event type and by subject (and advanced filters) so a mallow-bend Function runs only for the blobs it cares about—for example event type Microsoft.Storage.BlobCreated and subject begins-with /orders. Filtering at the subscription keeps unused subjects from waking the Function.
Using a Service Bus SQL filter on a queue even though the source is Event Grid fails the control point: if Event Grid is delivering, narrow delivery with Event Grid subscription filters first; a Service Bus filter only helps after you have redirected into Service Bus.
Deleting the system topic and polling every container from a timer fails because it abandons eventing for inefficient listing and removes the built-in Azure event source.
Sending all blobs to every Function and ignoring unused subjects fails cost and correctness: every create still invokes the Function, which is the opposite of narrowing delivery.
Exam caveat: subject filters depend on the subject shape the publisher emits (for blobs, the subject includes the blob path)—test the prefix against real events. Operational check: configure begins-with /orders (or equivalent), upload blobs under /orders and under another prefix, and confirm only /orders creates invoke the Function.