Allow specifying a default EntityPath for Azure Event Hubs / Azure Service Bus connection string

[oising]

Is there an existing issue for this?

• I have searched the existing issues

Is your feature request related to a problem? Please describe the problem.

Can we add support for setting an EntityPath in the connection string now that the application model is stable. Having to set the EventHubName via the settings callback for integrations is bothersome.

Describe the solution you'd like

An API extension like the following seems the least intrusive:

builder.AddAzureEventHubs("ns").WithHub("hub", configure => configure.IsDefaultEntity = true);

...would result in the following connectionstring being available to integrations:

Endpoint=sb://<NamespaceName>.servicebus.windows.net/;SharedAccessKeyName=<KeyName>;SharedAccessKey=<KeyValue>;EntityPath=hub

Not setting a default entity should result in a connection string for the namespace only. The builder should throw [on build?] if more than one hub is set as default. I presume this should also work the same for ASB queues etc.

Additional context

No response

[eerhardt]

cc @sebastienros

[oising]

I just threw up an initial PR for this -- have at it, @davidfowl @mitchdenny

I know this requires an API review officially, but I get the feeling you've had a dozen on this already internally. Maybe since the work is done, it will make the decision easier...