How to check if a field exists in the Ruby plugin?

Elastic Stack Logstash
1

Hi,

I am trying to find how to check if a field exist in the ruby filter.

To check the existence of a field in Ruby, I tried the following three, seems that none of them work

if event['duration']['time'] =~ /.+/
if event['duration']['time'] != nil
if(event['duration']['time'])

Any suggestions?

My code is like:

filter {
json {
source => "message"
}
if [profiling][method] =~ /.+/ {
ruby {
code => "
if(event['duration']['time'])
event['timeStart'] = event['timeEnd'] - event['duration']['time']
end"
}
}
}