snapcraft --use-lxd should have message about requring sudo

[Hayden Barnes]

Running $ snapcraft --use-lxd will set up LXD but it will not connect:

hayden@ubuntu:~/ghost-desktop$ snapcraft --use-lxd
Support for 'LXD' needs to be set up. Would you like to do that it now? [y/N]: y
snapd is not logged in, snap install commands will use sudo
lxd 3.21 from Canonical✓ installed
Error: LXD still not running after 30s timeout (Get http://unix.socket/1.0: dial unix /var/snap/lxd/common/lxd/unix.socket: connect: permission denied)
Timeout reached waiting for LXD to start.

Then, naturally, you try $ sudo snapcraft --use-lxd but get this:

hayden@ubuntu:~/ghost-desktop$ sudo snapcraft --use-lxd
The LXD provider is offered as a technology preview for early adopters.
The command line interface, container names or lifecycle handling may change in upcoming releases.
Launching a container.
An error occurred with the instance when trying to launch with 'LXD': No storage pool found. Please create a new storage pool.
Ensure that 'LXD' is setup correctly and try again.

The fix is to $ snap remove lxd --purge and then $ sudo snapcraft --use-lxd.

Because using snapcraft --use-lxd without sudo leaves it in an unusable state, perhaps it should fail and exit if --use-lxd is enabled without sudo.

[Chris Patterson (cjp256)]

`sudo` shouldn't be required when invoking snapcraft. As you can see in the log, snapcraft invokes sudo on your behalf when installing LXD.

However, I think we may need to add/check that the user is in the "lxd" group if not run as sudo? Can you verify that your user is not in the "lxd" group?