udp_logger.rb

require "socket"
require "time"
require "syslog/logger"

module Syslog
  class UDPLogger < Logger
    attr_reader :socket

    def initialize(tag, host = "127.0.0.1", port = 514)
      @host = host
      @port = port
      @tag = tag
      @level = ::Logger::DEBUG
      @formatter = Formatter.new
      @socket = UDPSocket.new
    end

    private

    def add(severity, message = nil, progname = nil, &block)
      severity ||= ::Logger::UNKNOWN
      if @level <= severity
        level = LEVEL_MAP[severity]
        message = formatter.call(severity, Time.now, progname, (message || block.call))
        socket.send("<1#{level}>#{syslog_time} #{hostname} #{@tag}[#{Process.pid}]: #{message}", 0, @host, @port)
      end
      true
    end

    def hostname
      @hostname ||= Kernel.send(:`, "hostname").strip
    end

    def syslog_time
      now.utc.iso8601(6).gsub(/Z$/, "+00:00") # just did not know how to get zone +00:00 with ruby
    end

    def now
      Time.now
    end
  end
end