Rollback does not work: undefined method `metadata`

[webmatze]

Rollback does not work for me at the moment.

bundle exec kuby -e production rollback

Results in:

error: undefined method `metadata' for #<Kuby::Docker::Spec:0x00007fe87030b168>
bundler: failed to load command: kuby (/Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/bin/kuby)
Traceback (most recent call last):
	25: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/bin/bundle:23:in `<main>'
	24: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/bin/bundle:23:in `load'
	23: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/bundler-2.3.7/exe/bundle:36:in `<top (required)>'
	22: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/bundler-2.3.7/lib/bundler/friendly_errors.rb:103:in `with_friendly_errors'
	21: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/bundler-2.3.7/exe/bundle:48:in `block in <top (required)>'
	20: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/bundler-2.3.7/lib/bundler/cli.rb:25:in `start'
	19: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/bundler-2.3.7/lib/bundler/vendor/thor/lib/thor/base.rb:485:in `start'
	18: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/bundler-2.3.7/lib/bundler/cli.rb:31:in `dispatch'
	17: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/bundler-2.3.7/lib/bundler/vendor/thor/lib/thor.rb:392:in `dispatch'
	16: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/bundler-2.3.7/lib/bundler/vendor/thor/lib/thor/invocation.rb:127:in `invoke_command'
	15: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/bundler-2.3.7/lib/bundler/vendor/thor/lib/thor/command.rb:27:in `run'
	14: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/bundler-2.3.7/lib/bundler/cli.rb:484:in `exec'
	13: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/bundler-2.3.7/lib/bundler/cli/exec.rb:23:in `run'
	12: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/bundler-2.3.7/lib/bundler/cli/exec.rb:58:in `kernel_load'
	11: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/bundler-2.3.7/lib/bundler/cli/exec.rb:58:in `load'
	10: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/bin/kuby:23:in `<top (required)>'
	 9: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/bin/kuby:23:in `load'
	 8: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/kuby-core-0.18.0/bin/kuby:6:in `<top (required)>'
	 7: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/kuby-core-0.18.0/lib/kuby/commands.rb:35:in `run'
	 6: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/gli-2.21.0/lib/gli/app_support.rb:85:in `run'
	 5: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/gli-2.21.0/lib/gli/app_support.rb:311:in `call_command'
	 4: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/gli-2.21.0/lib/gli/app_support.rb:298:in `block in call_command'
	 3: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/gli-2.21.0/lib/gli/command_support.rb:131:in `execute'
	 2: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/kuby-core-0.18.0/lib/kuby/commands.rb:187:in `block (2 levels) in <class:Commands>'
	 1: from /Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/kuby-core-0.18.0/lib/kuby/tasks.rb:144:in `rollback'
/Users/mathiaskarstaedt/.asdf/installs/ruby/2.7.4/lib/ruby/gems/2.7.0/gems/kuby-core-0.18.0/lib/kuby/kubernetes/spec.rb:184:in `rollback': undefined method `metadata' for #<Kuby::Docker::Spec:0x00007fe87030b168> (NoMethodError)

It looks like instead of docker.metadata.previous_tag it should be docker.image.previous_version or something different (/lib/kubernetes/spec.rb:183)?

If you want I can try to provide a PR with a fix.

[camertron]

Woops! Yes, a PR would be greatly appreciated :)