How can we send response to Custom Event Grid Topic publisher from subscriber

Question

As Event grid custom topic is an http endpoint which is used by the publisher to raise an event, whereas the event grid custom topic having a webhook endpoint of a subscriber. How can I can send response back to the publisher from subscriber via event grid custom topic routing back ?

For request/reply scenarios Azure Service Bus might be more suitable for some scenarios. You can have pub/sub and replies can be sent directly to the destination supplied to the address supplied to the subscribers via ReplyTo of the messages. — Sean Feldman

Roman Kiss Roman Kiss · Accepted Answer · 2020-08-01T10:00:12

The Azure Event Grid (AEG) is the Pub/Sub loosely decoupled model. In other words, the publisher doesn't have any glue about the subscriber(s), such as how many subscribed, who subscribed, etc., it's a full decoupled eventing model. The same decoupling is also between the subscribers.

During the publisher posting an event to the AEG, the response is sent back to the publisher, see more details here. Basically, this response code indicated if the request with an event payload is accepted for delivery, that's the code=200 or the request failed (no event delivery).

Note, that there is no way in the present version of AEG for custom handling the response code to the publisher, in other words, the publisher can successful fired an event to the AEG without any subscriber on its topic.

However, the subscriber can be also a publisher of the event message to the AEG and the same, the publisher can be also a subscriber, so based on the data object of the event message, the subscriber can notify a publisher in the loosely decoupled manner via the AEG model, see the following sequential diagram:

How can we send response to Custom Event Grid Topic publisher from subscriber

1 Answers