create_table.rb

#!/usr/bin/env ruby
$:.unshift File.dirname(__FILE__) + '/../../lib/'
require 'rubygems'
require 'q4m'

database = "test_q4m"
table = "example_json_queue_monitor"
sql = "CREATE TABLE IF NOT EXISTS #{table} (v TEXT NOT NULL) ENGINE=QUEUE;"

begin
  dbh = DBI.connect "DBI:Mysql:database=#{database}", "root", ""
  dbh.do sql
rescue
  p "ERROR: #{$!}"
end

enqueue.rb

$:.unshift File.dirname(__FILE__) + '/../../lib/'
require 'rubygems'
require 'q4m'
require 'json'

q = Q4M.connect :connect_info => ['DBI:Mysql:database=test_q4m', 'root', '']
table = 'example_json_queue_monitor'

puts '[client] write message:'
input = gets
data = {:message => input, :time => Time.now}
q.insert(table, :v => data.to_json)

monitor.rb

# 適当にjsonでしまっとくサンプル
$:.unshift File.dirname(__FILE__) + '/../../lib/'
require 'rubygems'
require 'q4m'
require 'json'

Signal.trap(:INT) do
  Q4M.disconnect
  p 'END'
  exit
end

q = Q4M.connect :connect_info => ['DBI:Mysql:database=test_q4m', 'root', '']
table = 'example_json_queue_monitor'
while q.next(table, 5)
  v = q.fetch(table)[0]
  data = JSON.parse(v)
  p "[DATA] time = #{data['time']}, message = #{data['message']}"
  p "...waiting..."
  sleep 1
end

Q4M.disconnect