调试使用事件网格触发的 Azure Function

Question

I have an Azure Function (C#) that is triggered by an Event Grid. I am having difficulty debugging my Function locally as it can only be triggered via the Event Grid.

I'm not sure if there is a way to wire the Event Grid up to my local host address for my Function? I have tried using a Web Hook but it only support HTTPS which my localhost uses HTTP.

public static void Run([EventGridTrigger]EventGridEvent eventGridEvent, ILogger log)
{
 ID = eventGridEvent.Subject;
 log.LogInformation($"ID: {ID.ToString()}");
}

Any advice is appreciated.

Answer 1

I found this blog post that helped me resolve this when debugging event grid azure function locally: https://blog.mcilreavy.com/articles/2018-12/debug-eventgrid-triggered-azure-function

One piece that was missing in my case was the aeg-event-type header. aeg-event-type: Notification

After adding it, I was able to debug locally using this url: http://localhost:7071/runtime/webhooks/EventGrid?functionName=nameOfYourFunction

And include this event json in the request body, something like this:

[ { "id": "'1", "eventType": "yourEventType", "eventTime":"10:59:00.000", "subject": "subject1", "data":{"make": "Ducati", "model": "Monster"}, "dataVersion": "1.0" } ]

Answer 2

Actually, there is a nice and easy way of doing this using a ngrok as a tunnel. So you basically create a EventGrid Subscription that publishes your events to your ngrok tunnel (eg https://ec291dd9.ngrok.io/runtime/webhooks/EventGrid?functionName=myfunc ) and start debugging your function in Visual Studio. You don't need to change your function at all.

This approach is also well documented from Microsoft: Azure Function Event Grid Trigger Local Debugging

Answer 3

You're right. At this moment, tooling for Event Grid is being improved and there's no easy way to test it locally.

In my Event Grid Functions, I'm separating the logic from the trigger part, this way I can unit test the logic without the need of a real event in order to test it. After that, I'm capturing the event through Application Insights and a log.LogInformation(eventGridEvent.Data.ToString());