invalid yaml produces cryptic error

[jpcarey]

Should improve the error thrown when an invalid yaml file is read from logstash.yml.

Current error:
ERROR: Failed to load settings file from "path.settings". Aborting... path.setting=/etc/logstash/, exception=Psych::SyntaxError, message=>(<unknown>): expected <block end>, but found BlockMappingStart while parsing a block mapping at line 155 column 2

• Version: 5.1.1
• Operating System: Cetos 7
• Steps to Reproduce:
  • Install RPM
  • In /etc/logstash/logstash.yml, uncomment line 155, leaving the space at the beginning of the line.
  • Start logstash, and you will get the error pasted above.

[jsvd]

We're limited to what the ruby's yaml parser gives us:

jruby-1.7.25 :017 > YAML.parse("teste:\n    teste.tet:\n  hey: - 1\n")
Psych::SyntaxError: (<unknown>): expected <block end>, but found BlockMappingStart while parsing a block mapping at line 3 column 3

The only option is to create a user friendly component that parses these messages, but it seems like a big time investment ..

[jpcarey]

I think if the error was more descriptive - that YAML.parse failed, and which file - that would be more than sufficient (along with the raw exception, which does contain the line number and character).

Maybe something like:
ERROR: Failed to parse YAML file: {{path.to.file}}. Aborting... path.setting=/etc/logstash/, exception=Psych::SyntaxError, message=>(<unknown>): expected <block end>, but found BlockMappingStart while parsing a block mapping at line 155 column 2

[jsvd]

@jpcarey makes sense, thank you for the suggestion

[suyograo]

Fixed in #6546