logstash config loop through fields

Question

ruby/logstash noob here using ELK stack.

I got a bunch of fields

[Message][Detail][Readout][Value1]

[Message][Detail][Readout][Value2]

[Message][Detail][Readout][Value3]

which I want to loop through using ruby in the logstash config.

Then I want to perform a simple operation on each, for example change them from hex to decimal e.g.

event.set('[currField]', event.get('[currField]').to_s.hex);

but I cant find the correct syntax using google.. any help appreciated.

I know the names of the fields, so worst case I'll have to hard code them, but I'd like to avoid that if possible.

EDIT: i have not tested my config yet, so i dont know if "Readout" will be a hash map; im using grok filter to add the values in the config

"(?<[Message][Detail][Readout][Value1]>(?<=0x.{8})([A-F0-9]{2}))",
"(?<[Message][Detail][Readout][Value2]>(?<=0x.{8})([A-F0-9]{2}))" 

etc

Pseudo:

event.get('[Message][Detail][Readout]') each { |k, v|
  event[k] = newValue;
}

Answer 1

You would use .each to iterate over the [Message][Detail][Readout] hash. Your pseudo-code would set the values at the top-level. To overwrite them use

ruby {
    code => '
        readout = event.get("[Message][Detail][Readout]")
        if readout
            readout.each { |k, v|
                event.set("[Message][Detail][Readout][#{k}]", v.to_s.hex)
            }
        end
    '
}