Add jsonhelper

[martinscholz83]

Helper lib to write json keys for an event. Also refactored #3169

[elasticmachine]

Jenkins standing by to test this. If you aren't a maintainer, you can ignore this comment. Someone with commit access, please review this and clear it for Jenkins to run.

[elasticmachine]

Jenkins standing by to test this. If you aren't a maintainer, you can ignore this comment. Someone with commit access, please review this and clear it for Jenkins to run.

[martinscholz83]

@ruflin, @andrewkroh Is there something more to do after creating a new package??

[martinscholz83]

Why i had to create a directory which has the same name like the go file to get this working??

[martinscholz83]

After chatting with @tsg, we decided to put helper into jsontransform.

[andrewkroh]

@maddin2016 Can you please add when to the list of allowed fields for the processor. Found it while testing.

Otherwise LGTM.

[martinscholz83]

Hi @andrewkroh, what when does mean?

[andrewkroh]

It's a conditional statement like:

processors:
- decode_json_fields:
    when.regexp:
      message: '^{'
    fields: message
    target: ''
- drop_fields:
    when.regexp:
      message: '^{'
    fields: message

[martinscholz83]

Ok, i asked because i don't find it at source code.

[andrewkroh]

This needs to be back ported to 5.2 to get the bug fix for the missing when condition.