In order to be able to trigger ubuntu-core image builds in response to an update to the set of snaps on the relevant channel, we would need to be able to query the snap store for cross-architecture information about the revisions on a channel.
$ snap info --arch armhf core
error: unknown flag `arch’
$
I understand from @mvo that there is currently no way to do this.
Yes, I think that is a valid workaround for now. I still think its worthwhile to provide a way via the “snap” command to get that data so that there is only a single implementation that talks to the store. I was thinking something like snap debug querty-store --arch armhf snap-name as the interfaces.