Set a nested field with a variable

[dwatbmc]

Can't find a way to do this with Mutate, so I am attempting it in Ruby, but still failing:

I have two fields:
[log][group] = "panos"
[log][type] = "threat"

Based on these two field values, I want to copy the JSON Object from [labels][group] to a new field [panos][threat], using the values in log.group and log.type, as they can change.

With Mutate:

mutate {  add_field => {"[%{[log][group]}][%{[log][type]}]" => "%{[labels][group]}"} }

This results in a JSON String, rather than the nested object structure. So using Ruby:

code => '
                    mygroup = event.get("[log][group]").to_s
                    mytype = event.get("[log][type]").to_s
                    myvalue = event.get("[labels][group]")
                    event.set("[mygroup][mytype]",myvalue)
                '

The last line with event.set - I can't figure out the syntax to reference the two variables to create the nested field.

Ideas?

[dwatbmc]

Found my own answer. For anyone else, the correct syntax:

event.set("[#{mygroup}][#{mytype}]",myvalue)