Logstash 2.4.0: Ruby exception occurred: undefined method `/'

[AlessandroC985]

I'm trying to modify the value of a numeric field (type long) with logstash 2.4.0 using the ruby filter.

This is my filter configuration:

ruby {
    code => "event.set('myField', event.get('myField') / 1000)"
}

I have the following error:

{:timestamp=>"2017-11-09T16:17:38.511000+0000", :message=>"Ruby exception occurred: undefined method `/' for "414886000":String", :level=>:error}

The "myField" field is correctly stored in elasticsearch, but it's not divided.

What's wrong?
Thanks.

[magnusbaeck (Magnus Bäck)]

The myField field is a string. Replace event.get('myField') with event.get('myField').to_i.

[AlessandroC985]

Perfect! That has solved the issue!

Just a curiosity: "myField" is stored as a "long" field in elasticsearch.
This means that in logstash is still a "String" type (before being pushed to Elasticsearch) ?

Thanks!

[magnusbaeck (Magnus Bäck)]

Yes. The type of the field in ES and the type of the corresponding field in the JSON document don't have to be equal, but a string value in the document can definitely be mapped as an integer (as long as the string can be parsed as an integer obviously).