Try to make a custom geokit logstash filter

geocoder.rb

# encoding: utf-8
require "logstash/filters/base"
require "logstash/namespace"
require "logstash/util/geolookup"


class LogStash::Filters::Geocoder < LogStash::Filters::Base
  # Setting the config_name here is required. This is how you
  # configure this filter from your logstash config.
  #
  # filter {
  #   foo { ... }
  # }
  config_name "geocoder"

  # New plugins should start life at milestone 1.
  milestone 1

  # Replace the message with this value.
  config :source, :validate => :string

  public
  def register
    @gl = Geolookup.new
  end # def register

  public
 
  def filter(event)    
    # return nothing unless there's an actual filter event
    return unless filter?(event)
    begin
    if @message
      
      result = @gl.reverse_geocoder(@message)
      # event["lat"] = result.lat
      # event["lng"] = result.lng
      event["latlng"] = reuslt.ll
      event["full_address"] = result.full_address
    end
    rescue => e
      event.tag("_geocodeparsefailure")
      @logger.warn("Trouble parsing geocode", :source => @source,
                   :raw => event[@source], :exception => e)
    end
    # filter_matched should go in the last line of our successful code 
    filter_matched(event)
  end # def filter

 
end # class LogStash::Filters::Foo

geolookup.rb

class Geolookup 
  require "geocoder"
  require "cache_method"
  def reverse_geocoder query
    Geokit::Geocoders::secure = false # disable ssl for poc
    Geokit::Geocoders::MultiGeocoder.geocode(query)
  end
  cache_method :reverse_geocoder
end # class Glookup