Problem with turn off dead-lettering

[romankiss]

I have successful turn on a dead-lettering using a REST API update (PATCH). Everything is working well. I can update (PATCH) any part of the deadLetterDestination property.

The problem is to turn off dead-lettering.
Removing a "deadLetterDestination":null doesn't work with REST API Update call.

Note, that the other property, for instance "labels":null can be succesfful removed.

Thanks
Roman

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Document Details

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• ID: 2ad5c953-fa75-9944-5539-111bfc52e892
• Version Independent ID: 00d37a17-4f7d-779e-8243-786c1d4dba7d
• Content: Manage delivery settings for Azure Event Grid subscriptions
• Content Source: articles/event-grid/manage-event-delivery.md
• Service: event-grid
• GitHub Login: @tfitzmac
• Microsoft Alias: tomfitz

[vasivara-MSFT]

@romankiss Thanks for the feedback. We are actively investigating and will get back to you soon.

[asergaz]

Hello @romankiss can you be more specific about the

REST API update (PATCH)

and the error seen when setting

"deadLetterDestination":null

? I can't see it being used on this doc where you opened the issue at.

The examples we provide on this doc are using Event Grid extension for Azure CLI.

storagename=demostorage
containername=testcontainer

storageid=$(az storage account show --name $storagename --resource-group gridResourceGroup --query id --output tsv)

az eventgrid event-subscription create \
  -g gridResourceGroup \
  --topic-name <topic_name> \
  --name <event_subscription_name> \
  --endpoint <endpoint_URL>
  --deadletter-endpoint $storageid/blobServices/default/containers/$containername

storagename=demostorage
containername=testcontainer

storageid=$(az storage account show --name $storagename --resource-group gridResourceGroup --query id --output tsv)

az eventgrid event-subscription create \
  -g gridResourceGroup \
  --topic-name <topic_name> \
  --name <event_subscription_name> \
  --endpoint <endpoint_URL>
  --deadletter-endpoint $storageid/blobServices/default/containers/$containername

Thank you!

[romankiss]

Thanks for prompt response.

The above document described how can be enabled a new feature of the subscription such as delivery a dead-letter to the blob storage destination.

This feature is declared by new property such as deadLetterDestination in the subscription properties. As the above document mentioned, the _deadLetterDestination_property (by default) doesn't exist it in the subscription, it must be turn on (added).

The document shows an example for creating a new subscription with a deadLetterDestination property using an Azure CLI.

Note, that the Azure CLI is based on the REST API calls. I am using a REST API (2018-05-01-preview) for turn on a dead-letter feature in the event grid subscription ( https://docs.microsoft.com/en-us/rest/api/eventgrid/eventsubscriptions/update).

As I mentioned, there is no problem to turn on a dead-lettering feature in the subscription, also there is no problem to update it.

The problem is to make turn off (removing) a dead-lettering in the subscription. The document shows how to turn on it, but it missing a way how to turn off a dead-lettering in the subscription. In other words, make a disable for dead-lettering in the subscription such as a default case.

Using an Azure CLI it should be the following:
az eventgrid event-subscription update --resource-id "xxxx" --name mySubscription --remove deadLetterDestination

it should be remove a deadLetterDestination property from the subscription, but this update doesn't have any effect on the subscription properties, in other words, we can not remove (turn off) the dead-lettering in the subscription when once it has been turn on or created.

I think, this is a bug and it should be fix it to allow turn on/off a dead-lettering in the subscription.

In the above document is missing an info with an example how to turn off a dead-lettering feature in the event grid subscription.

Thanks

[asergaz]

Hello @romankiss and thank you for the clarification. I also did some tests on my own and I also couldn't
set deadLetterDestination null again (Azure CLI or REST). Since this is still in preview I believe there should be some work in progress to address that, but I will get a confirmation from the Product Group and let you know.

As a workaround can you please remove the subscription and recreate it with the same name? That would set deadLetterDestination to null again.

1. Delete:

az eventgrid event-subscription delete -g rg1 --topic-name topic1 --name es1

2. Recreate:

az eventgrid event-subscription create \
  -g rg1 \
  --topic-name topic1 \
  --name es1 \
  --endpoint <endpoint_URL>
  --deadletter-endpoint $storageid/blobServices/default/containers/$containername

Truly appreciate your feedback!

[tfitzmac]

@romankiss - thanks for this feedback. We are looking into this issue. The suggestion from @sergaz-msft is a good option for now. Hopefully, we will soon know if there is another way to turn off deadlettering or a fix on the way.

[romankiss]

Thanks for responses. I hope, that this bug will be resolved. There is no good option for replacing a patching (updating) a portion of the event subscription. The above suggestion requires to make multiple calls such as:

• get the event subscription
• get the full endpointUrl
• delete subscription
• creating a new subscription without the deadLetterDestination

Note, that the patching of the deadLetterDestination property is working, just the problem is to remove it (such as "deadLetterDistination":null)

Thanks

[tfitzmac]

@romankiss - you can remove the dead letter destination by just re-running the create command without deadletter-endpoint. You don't need to delete it first.

[romankiss]

@tfitzmac - for "just re-running" the create command without deadletter-endpoint means to get in prior all values of the event subscription, such as:

• get the event subscription
• get the full endpointUrl

so, in other words, instead of the single PATCH call, we have to call GET, GET, PUT + some necessary coding for properties. That's done in the REST API today, when the deadLetterDestination property must be removed from the event subscription.
It is definitely a bug.

[tfitzmac]

@romankiss - I have forwarded your feedback, but you should also add it to feedback forum.