fix(snapd): ubuntu do not snap refresh when snap absent

[blackboxsw]

Proposed Commit Message

fix(snapd): ubuntu do not snap refresh when snap absent

No longer call snap refresh when cloud-config user-data specifies upgade_packages:true and custom Ubuntu images do not have snapd package installed

LP: #2064300

Additional Context

My commit a6f7577 attempted to fix this issue, but the validation of the fix only looked at
update_packages: true config not upgrade_packages: true

During SRU validation we discovered that this former patch was not successful in closing the upgrade patches case.
https://bugs.launchpad.net/ubuntu/+source/cloud-init/+bug/2064132

Test Steps

#!/bin/bash
set -ex
SERIES=$1

cat > pkg-upgrade.yaml <<EOF
#cloud-config
package_upgrade: true
EOF

#for SERIES in "focal" "jammy" "mantic"; do
for SERIES in "focal"; do
echo "---------- SRU verification: $SERIES"
name=test-no-snap-$SERIES
if [ "$SERIES" = "focal" ]; then
  LXC_CFG_KEY="user.user-data"
else
  LXC_CFG_KEY="cloud-init.user-data"
fi
lxc launch ubuntu-daily:$SERIES $name -c $LXC_CFG_KEY="$(cat pkg-upgrade.yaml)"
sleep 6
lxc exec $name -- cloud-init status --wait && echo "SUCCESS: upgrade success on system  with snapd" || echo "FAILED: package_upgrade error on system with snapd"

# assert snap refresh is called on system with snapd
lxc exec $name -- egrep 'snap.*refresh' /var/log/cloud-init.log && echo "SUCCESS: found snap refresh on system with snapd" || echo "FAILED: did not file snap refresh on system with snapd"

lxc exec $name -- apt-get remove snapd -y
lxc exec $name -- cloud-init clean --logs --reboot
sleep 6

lxc exec $name -- cloud-init status --wait || true # expect failure here because we aren't using the fixed version
lxc exec $name -- egrep 'snap.*refresh' /var/log/cloud-init.log && echo "SUCCESS: found snap refresh on failed system without snapd" || echo "FAILED: did not find snap refresh on failed system with snapd"

echo --- upgrade to proposed fix
lxc file push cloudinit/distros/ubuntu.py $name/usr/lib/python3/dist-packages/cloudinit/distros/
lxc exec $name -- cloud-init clean --logs --reboot
sleep 6

# expect no warnings/errors
lxc exec $name -- cloud-init status --wait --format=yaml || echo "FAILED: errors or warning found"

# ensure no calls to snap refresh
lxc exec $name -- egrep 'snap.*refresh' /var/log/cloud-init.log && echo "FAILED: found snap refresh system without snapd" || echo "SUCCESS: did not find snap refresh on system without snapd"

done

Checklist

• My code follows the process laid out in the documentation
• I have updated or added any unit tests accordingly
• I have updated or added any documentation accordingly

Merge type

• Squash merge using "Proposed Commit Message"
• Rebase and merge unique commits. Requires commit messages per-commit each referencing the pull request number (#<PR_NUM>)

[TheRealFalcon]

We'll handle all of the cases one of these days!

Looks good once lints are fixed