You can!!
ruby {
code => '
event.set("[file-suffix]", event.get("[file-suffix]") + 5.5)
logger.info("the file-suffix is:", "value" => event.get("[file-suffix]"))
'
}
logs this
[2018-04-18T09:34:55,590][INFO ][logstash.filters.ruby ] the file-suffix is: {"value"=>13.5}
you can use logger.error(), logger.warn(), logger.info(), logger.debug(), logger.trace()
Each of these methods has the same arguments <string>, <hash> (optional)
The hash is written as <string> => <any object>. You do not need to wrap the hash argument in the Ruby {} bracket although you can if you want.