The prior change to pre-seed the correct base added a case to handle
installation of the core snap. When that was added it created a case
where the $core_snap variable would not be defined when we reach the
end of the _snap_preseed function and evaluate if $core_snap is defined
by empty. Previous if the snap to preseed was core or core18 then
$core_snap would be "" so this patch addresses that by ensuring the
variable exists and is empty by default.
With the removal of snap-tool failures are seen in image builds that do
not have the 'core' snap included by the seed. This is the case for the
minimized subproject of the ubuntu-cpc project where lxd/core is removed.
In that subproject, any binary hook which adds a snap that is based
on 'core' will not add 'core' and fail 'snap debug validate-seed'.
snap-tool included the following logic in the 'snap-tool info' when
determining snap bases:
# Have "base" initialized to something meaningful.
if self.is_core_snap():
snap_data["snap"]["base"] = ""
elif snap_data["snap"].get("base") is None:
snap_data["snap"]["base"] = "core"
The snap store does not return a base if the base is core which makes
this necessary. This patch looks for the base in 'snap info' output
and if none is found (and the snap is not snapd or core) it assumes the
base is 'core' and installs it. This restores the behavior lost in the
migration from snap-tool to snap cli.
snap-tool was added to support a deprecate cohort-key feature of the
snap store. Recent changes in snap assertions have added additional
fields which snap-tool is not retrieving. This resulted in snap install
failures on first boot.
This patch removes snap-tool and returns to using the snap cli.
This ensures snap downloads will function without odd incompatibilities.
When we encounter a failure in 'lb binary' the launchpad builders can
only surface the build output from stdout. If the binary hook failure
implicates the archive we can not determine fault without the apt
proxy log. This patch will dump the proxy log to stdout to aid in
debugging these failures.
