Request: CUPS Snap (“cups”) auto connection to of cups:cups-control to cups:admin and also of the network-manager-observe interface

[jamesh]

slots-per-plug is something that would go in the snap declaration published by the store. It is not something you can control from your snapcraft.yaml file. This is the last time I made a request for such a declaration:

Auto-connect and greedy plug behaviour for for gtk-common-themes and gtk-theme-traditionalhumanized snaps

I’m making this request in relation to testing automatic theme installation. I’d like two changes: allow any snap to auto connect to gtk-theme-traditionalhumanized's gtk-2-themes and gtk-3-themes slots. update the declaration for gtk-common-themes and gtk-theme-traditionalhumanized snaps to allow greedy connection for their gtk-2-themes and gtk-3-themes slots. I believe the snap declaration syntax I’m requesting is as follows: slots: content: allow-auto-connection: - plu…

Back then, there was no policy for granting this type of request, so it was handled in an ad-hoc fashion. I’m not sure what the status is now.

Now for some other questions:

1. You’ve got both plugs and slots for the cups and cups-control interfaces, with the plugs taking the default name, and the slots named printing and admin respectively. Given that Most other snaps will generally be dealing with the CUPS snap’s slots, might it make more sense to give the slots the default names?

   With things like it is, it seems likely that people will try commands like sudo snap connect app:cups-control cups:cups-control and then get confused about them not working.

2. Does your snap actually need a cups plug? I would have thought the utility commands would have enough access to the CUPS socket through the cups-control slot.

3. I can see the cups-control plug as being necessary in order for the snapctl is-connected checks to pass and allow administrative commands like lpadmin to do their thing.

   I wonder if we could solve this by adding one more exit code to the is-connected command representing “not connected, but from the same snap”. That might be enough to get the bundled admin utilities to function without the plug. What do you think?