Field reference for Numbers

[redX]

Can I use field references for number fields?

For example I have an aggregate filter with a timeout. The timeout configuration expects a number. I have:

if [type] == "start" {     
	aggregate {
		task_id => "%{filename}"
		code => "[...]"
		map_action => "create"
	}
}

if [type] == "end" {
	aggregate {
		task_id => "%{filename}"
		code => "[...]"
		map_action => "update"
		end_of_task => true
		push_map_as_event_on_timeout => true
		timeout => 7200
		timeout_code => "[...]"
	}
}

The timout is hardcoded to 7200 seconds. I would like to set it via a field reference.
It is documented for strings here: https://www.elastic.co/guide/en/logstash/current/event-dependent-configuration.html#logstash-config-field-references
Is it possible to do this for numbers? I tried:

• timeout => "[timeout]" (timeout was a field on the event)
• timeout => "%{timeout} (I pushed the timout to the map beforehand)

But for both variants I get:

• This setting must be a number. Expected number, got "[timeout]" (type [timeout])
• or This setting must be a number. Expected number, got "%{timeout}" (type %{timeout})

It is documented to work for environment variables: https://www.elastic.co/guide/en/logstash/current/environment-variables.html

Is it possible to use field references in place of an expected number?