JSON output is not generated in case of traceback.

[phracek]

The command was:
$ colin check --json fedora.json -r fedora fedora:27

The code is here:

$ colin check --json fedora.json -r fedora fedora:27
LABELS:
nok:failed:maintainer_label_required
   -> Label 'maintainer' has to be specified.
   -> The name and email of the maintainer (usually the submitter).
   -> https://fedoraproject.org/wiki/Container:Guidelines#LABELS
nok:failed:name_label_required
   -> Label 'name' has to be specified.
   -> Name of the Image or Container.
   -> https://fedoraproject.org/wiki/Container:Guidelines#LABELS
nok:failed:com_redhat_component_label_required
   -> Label 'com.redhat.component' has to be specified.
   -> The Bugzilla component name where bugs against this container should be reported by users.
   -> https://fedoraproject.org/wiki/Container:Guidelines#LABELS
[..snip..]
nok:warning:io.openshift.expose-services_label
   -> Label 'io.openshift.expose-services' has to be specified.
   -> port:service pairs separated with comma, e.g. "8080:http,8443:https"
   -> ?????
Failed to mount OverlayFS device.
mount: only root can use "--options" option

16:38:17.688 colin.py          ERROR  An error occurred: ColinException("Problem with mounting filesystem with atomic. (Command '['atomic', 'mount', 'fedora:27', '/tmp/conuwzyyvd3g']' returned non-zero exit status 1.)",)
Error: Problem with mounting filesystem with atomic. (Command '['atomic', 'mount', 'fedora:27', '/tmp/conuwzyyvd3g']' returned non-zero exit status 1.)

[phracek]

Test is import for this case.

[TomasTomecek]

I propose to provide the image content not via mount, instead using docker create -name c $image; docker export c | tar -xf) so that we don't need root.

[phracek]

JSON output is already generated even if mounting file system fails.

[lachmanfrantisek]

Yes, I've corrected it as a side effect in #90 ...;-)