Class: LogStash::Filters::Redis

Inherits:
Base
  • Object
show all
Defined in:
lib/logstash/filters/redis.rb

Overview

A general search and replace tool which queries replacement values from a redis instance.

This is actually a redis version of a translate plugin. <www.elastic.co/guide/en/logstash/current/plugins-filters-translate.html>

Operationally, if the event field specified in the “field” configuration matches the EXACT contents of a redis key, the field’s value will be substituted with the matched key’s value from the redis GET <key> command.

By default, the redis filter will replace the contents of the matching event field (in-place). However, by using the “destination” configuration item, you may also specify a target event field to populate with the new translated value.

Alternatively, for simple string search and replacements for just a few values you might consider using the gsub function of the mutate filter.

Instance Method Summary collapse

Instance Method Details

#filter(event) ⇒ Object 



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# File 'lib/logstash/filters/redis.rb', line 77

def filter(event)
  return unless event.include?(@field)
  return if event.include?(@destination) and not @override

  source = event.get(@field).is_a?(Array) ? event.get(@field).first.to_s : event.get(@field).to_s
  @redis ||= connect
  val = @redis.get(source)
  if val
    begin
      event.set(@destination, JSON.parse(val))
    rescue JSON::ParserError => e
      event.set(@destination, val)
      #event.set("redis-error", "Cannot parse JSON: " + e.to_s)
    end
  elsif @fallback
    event.set(@destination, @fallback)
  end
    
  # filter_matched should go in the last line of our successful code
  filter_matched(event)
end

#register ⇒ Object 



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# File 'lib/logstash/filters/redis.rb', line 70

def register
  require 'redis'
  require 'json'
  @redis = nil
end