Azure function app's signalr_extension is not populated to use in signalR upstreams when creating a 'non-consumption plan' function app by Bicep

[Arash-Sabet]

Bicep version
v0.6.18

Describe the bug
The title of this issue states the issue.

To Reproduce
I created an Azure Function App by Bicep and tried to get the signalr_extension's value to use in the "upstream" configuration section of a serverless Azure SignalR Service. This code illustrates how to obtain this value in Bicep:

var signalRKey = listKeys(resourceId('Microsoft.Web/sites/host', funcAppName, 'default'), '2022-03-01').systemkeys.signalr_extension

The signalR service's upstream configuration:

urlTemplate: 'https://${funcAppName}.azurewebsites.net/runtime/webhooks/signalr?code=${signalRKey}'

Running the bicep templates leads to the failure below:

Encountered an error (ServiceUnavailable) from host runtime.

When I remove the {signalRKey} from urlTemplate and replace it with a fictitious hard-coded value, the signalR is provisioned successfully.

The other thing that I noticed was that the singalr_extension key value was not populated after the function app was provisioned.

What am I missing in this exercise?

Additional context
This Stackoverflow post has comprehensive information including the bicep template on duplicating this issue. Apparently, signalr_extension is populated only when the function app is provisioned to be on the consumption plan. Using app service plans like B1, B2, or S1, etc., causes the bicep template to fail to have signalr_extension created and populated.

[alex-frankel]

This does not look to be a bicep specific issue. Someone in this repo may know the answer, but you may also need to open up a support case to get a more direct answer from the Azure Functions team.

[Arash-Sabet]

Will do. Thanks.

[thomasmendicino]

Hi, was there a resolution for this issue that you brought up? I am encountering the same problem and would like to know if there is a solution. Thank you

[Arash-Sabet]

Azure cannot support this feature.

[Arash-Sabet]

Azure App Service plan does not support this feature even though the bicep script may seem legitimate.