show build backend used on --debug

[anatoly techtonik]

snapcraft is slow and I can't check why. It probably ignores my LXD and uses some heavy-weight VM mechanism. It would be useful to get some info which VM backend is used when debug flag is specified.

$ snapcraft --debug
Using 'snap/snapcraft.yaml': Project assets will be searched for from the 'snap' directory.
Launching a VM.
Retrieving image: 6%^C
Aborted!

[mase (i-lp-f)]

From https://snapcraft.io/docs/build-on-lxd

As of version 3.4+ it's possible to request building with LXD using either
snapcraft --use-lxd

or

$ export SNAPCRAFT_BUILD_ENVIRONMENT=lxd

The latter appears to work in snapcraft, version 2.43.1+18.4

[anatoly techtonik (techtonik)]

It still doesn't solve the problem of detecting which backend is actually used.