Allow-list for server extensions?

[krassowski]

Problem

I would like to run a simple jupyter-server with a single extension and enforce that no other extensions are picked up. This does not appear to be currently possible.

--ServerApp.jpserver_extensions allows to toggle off individual extensions if these are known, but there is no way to disable all and only enable select few.

Proposed Solution

Maybe --ServerApp.jpserver_extensions_allow_list which takes precedence over --ServerApp.jpserver_extensions?

Additional context

JupyterLab has an allow list and a block list for frontend extensions.

[krassowski]

I guess the closest thing to this is load_other_extensions in ExtensionApp. My problem right now is that this does not play nicely with JupyterHub which requires a ServerApp