Error in parameter yaml is very hard to track down

[andrewjhumphrey]

I had an error in a parameter YAML file:

ami:
  latest_ami:
    owners: <SNIP>
      filters:
        name: not-for-public-consumption-*

Note the extra spaces in front of the filters element.

The error that stack_master produces does not reference the file that cause it at all, making it somewhat of a pain to track down.

 sm apply us-west-2 not-for-public-consumption --trace
Executing apply on not-for-public-consumption  in us-west-2
/usr/local/var/rbenv/versions/2.2.4/lib/ruby/2.2.0/psych.rb:370:in `parse': (<unknown>): mapping values are not allowed in this context at line 4 column 13 (Psych::SyntaxError)
    from /usr/local/var/rbenv/versions/2.2.4/lib/ruby/2.2.0/psych.rb:370:in `parse_stream'
    from /usr/local/var/rbenv/versions/2.2.4/lib/ruby/2.2.0/psych.rb:318:in `parse'
    from /usr/local/var/rbenv/versions/2.2.4/lib/ruby/2.2.0/psych.rb:245:in `load'

Would be nice if there was something in the trace that told you the file that went boom, to avoid having to manually call YAML.load_file on each yaml file in turn to find the culprit.

[simpsora]

I'm also running into the same problem. In my case it was a very similar problem of incorrect indentation, but in stack_master.yml rather than a parameters file.

[rbayerl]

We run a style test suite that consists of rubocop (for Sparkleformation templates), flake8 (for Lambda code), and yamllint (for stack_master configuration and parameter files). Perhaps incorporating something similar in your workflow or CI would be more useful than adding a YAML linter to stack_master.