How to create a Webhook subscription for Azure Event-Grid

Question

I wanted to prototype a service using azure event-grid and used the following resources to create a custom event-grid topic. I'm trying to add a webbook subscription but there is a mandatory field (system topic name) on the Azure Portal that's not explained in the docs, and cli fails with the error below.

CLI Error: Deployment failed. Correlation ID: 9e13c3c8-4255-4a0c-b5b5-0a9419a385dd. The operation failed due to an internal server error. The initial state of the impacted resources (if any) are restored. Please try again in few minutes. If error still persists, report 698c81db-22a9-4e4a-91cf-55408b2b1486:6/2/2020 8:23:10 AM (UTC) to our forums for assistance or raise a support ticket .

Portal Error: Creation of System Topic has failed with error: System topic creation is not enabled for topic type Microsoft.EventGrid.Topics

Resources: https://docs.microsoft.com/en-us/azure/event-grid/scripts/event-grid-cli-create-custom-topic https://docs.microsoft.com/en-us/azure/event-grid/scripts/event-grid-cli-subscribe-custom-topic https://docs.microsoft.com/en-us/azure/event-grid/custom-event-quickstart-portal

I'm not sure what I'm doing wrong. Any help is much appreciated.

Thank you

Answer 1

It looks like this is a bug on the portal. Based on the System topics in Azure Event Grid document:

System topic isn't applicable to custom topic scenarios, that is, Event Grid topics and Event Grid domains.

As a workaround, you can use any value for System Topic Name property to create the Event Subscription via the portal.

The following screen snippet shows a portal notifications during a process of the Event Subscription creating and deploying.