The retry will happen even when the event was delivered successfully.

[foolisheep]

This is unexpected. Can we only send the event when the delivery was failed?

[tonesandtones]

I've just hit this problem too. When used with Azure Functions, the az func core tools runtime responds with 202 Accepted instead of 200 OK. Returning anything other than 200 OK causes the emulator to retry the message even though it doesn't need to.

This comes from SubscriberConstants.NonRetriableStatusCodes

wl-eventgrid-emulator/src/EventGridEmulator/Network/SubscriberConstants.cs

Lines 11 to 21 in 2650953

	public static readonly HashSet<HttpStatusCode> NonRetriableStatusCodes = new HashSet<HttpStatusCode>
	{
	// Of course we let HTTP 200 pass through
	HttpStatusCode.OK,
	// Those cannot be retried based on Event Grid's documentation
	// https://learn.microsoft.com/en-us/azure/event-grid/delivery-and-retry#retry-schedule
	HttpStatusCode.BadRequest,
	HttpStatusCode.RequestEntityTooLarge,
	HttpStatusCode.Unauthorized,
	};

I know https://github.com/gsoft-inc/wl-eventgrid-emulator/blob/main/CONTRIBUTING.md says you don't accept external PRs, but I've forked and fixed the problem for my own use at https://github.com/tonesandtones/wl-eventgrid-emulator/tree/81-prevent-retry-on-2xx-status. I'm happy to put up a PR if you're interested.