Using Ruby filter in logstash to sum values of a field everytime that event appears

Question

I'm trying to sum the value of a specific field every time it shows, the field is in this format: [cdr][Service-Information][PS-Information][Service-Data-Container][Accounting-Output-Octets] and its value is a numeric field (it shows the number of bits consumed).

What I'm trying to do is the following:

a = event.get("[cdr][Service-Information][PS-Information][Service-Data-Container][Accounting-Output-Octets]")
if a
    sum = 0
    a.each_index { |x|
        sum += a["amount"]
    }
    event.set("amount-sum", sum)
end

I'm getting the following error:

Ruby exception occurred: undefined method `each_index' for Integer

I am a newbie in Ruby, so I've got no idea if this code serves for this type of field too.

Answer 1

If a is integer You can use something like this:

a = 123456789
a = a.to_s.split("").map(&:to_i)
sum = 0
a.each do |x|
  sum += x
end
p sum #=> 45

And please DO NOT USE brace if block is not in one line. Here I did it with do end just to show how it must be. If You want to use one line block - You must write like that:

a.each {|x| sum += x} 

if block > 1 lines than use do/end | else { }