json_file_gz codec for Logstash, to handle gzipped json files handled to it as file names in the input stream. Details: http://speakmy.name/2014/01/13/gzipped-json-files-and-logstash/

## json_file_gz.rb
# encoding: utf-8
require 'logstash/codecs/base'

class LogStash::Codecs::JsonFileGz < LogStash::Codecs::Base
  config_name 'json_file_gz'
  milestone 1

  public
  def register
    require 'zlib'
  end

  def decode(path)
    begin
      json_data = Zlib::GzipReader.open(path) { |f| f.read }
    rescue Zlib::GzipFile::Error => e
      @logger.info('Gzip failure, skipped', :error => e, :data => json_data)
    end

    begin
      yield LogStash::Event.new(JSON.parse(json_data)) if json_data
    rescue JSON::ParserError => e
      @logger.info('JSON parse failure. Falling back to plain-text', :error => e, :data => json_data)
      yield LogStash::Event.new('message' => json_data)
    end
  end # def decode

  def encode(data)
    raise NotImplementedError
  end # def encode

end # class LogStash::Codecs::JsonFileGz