About Event Grid System Topic dead-lettering

Question

Hi,

I have a Event Grid Sytem Topic that forwards "Blob Created" events to Event Hub. Everything is well so far.

When configuring dead lettering, I set up an Storage Account as destination. When proven, events are store in json format in this Storage Account.

However, when setting up a Function to pick the event from the Storage Account and send it back to Event Grid, I read that that System Topics don't support API or SDK for publishing. This makes sense to me, since Azure services should be the only ones allowed to publish them.

I don't know how to re-send those events to Event Grid, so that the can have a ful event delivery cycle again. ¿what is the recommended architecture in this case?, ¿Should I create other Event Grid resource like Custom Topics that fordwards events to Event Hubs?

Regards

Answer 1

Hi @Jona Greetings! Thank you for posting this question here.

As you stated in the question, we cannot explicitly send a message/event to a System Topic in Event grid. There are a couple of options you can try here.

1. Create a custom topic in the event grid and route the events from the Storage account to this queue. You would need to subscribe to this topic and create a same flow to process the Blob
2. Alternatively, if the time of the blob creation event is not a priority, you can leverage the Blob Storage SDK to delete the blob and reupload it. This would trigger a Blob created event which would then be processed by your Event Grid System Topic.

You can choose either approach that suits your needs.

---

If the response helped, please do click Accept Answer and Yes for the answer provided. Doing so would help other community members with similar issue identify the solution. I highly appreciate your contribution to the community.