Request: Printing Stack Snap auto connection to avahi-control, raw-usb, and home interfaces

I am leading the OpenPrinting project and as a part of it I am maintaining the printing-stack-snap:

This snap is working so far for printing from both snapped applications and classically installed applications.
It needs the following three interfaces and currently they need to get set up manually:
  • avahi-control: Network printers and also remote CUPS printers advertise themselves via Avahi. CUPS and cups-browsed pick up these Avahi records to automatically create print queues to point to these printers. In addition, CUPS needs access to Avahi to advertise shared local printers to remote machines.
    On classic systems the snap needs to auto-connect to the system’s avahi-control interface, on Core systems to the avahi-control interface of the avahi snap.
  • usb-raw: This interface allows CUPS and its backends to connect to USB printers (on both classic and snap-based systems).
  • home: This is to access the user’s home directory for printing files located there. By default, snaps only auto-connect to home on classic systems. the printing-stack snap also needs to auto-connect to home on Core systems.

See also the file of the snap.


1 Like

+1 for avahi-control and usb-raw

It isn’t clear to me why home needs to be auto-connected in Ubuntu Core since core devices don’t typically have user sessions where people are using, for example, cups-pdf. Can you describe this use case more?

1 Like

With home I was thinking about doing something like lp -d <file>, <file> being in the user’s home directory, if this makes sense on Core systems.

Thanks for the additional information. IMHO, this doesn’t make sense on an Ubuntu Core to have by default. -1 for auto-connecting home.

@amurray, @popey, @kyrofa, @natalia, @mvo - can one/all of you vote?

I’m inclined to agree. I don’t see a massive problem if you’re doing printing on core that you can snap connect home or put the files you want to print somwhere lp can get them?
So +1 for avahi-control and usb-raw.

2 votes for, 0 against for raw-usb and avahi-control. I’ve granted auto-connection for these. This is now live.

0 votes for, 2 votes against for home.

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