stat_to_redis.rb

require 'redis'
require 'thread'

# Redis DataBase interface to save collected statistic
# new object apply any of the following parameters if needed:
# :host if you need to connect to an external host instead of the default 127.0.0.1
# :port if you need to use something other than Redis' default port of 6379
# :password if you configured Redis to require a password on connection
# :db if you want to select one of the multiple configured databases, other
#    than the default of 0 (databases are identified by a zero-based index)
# :timeout if you want a different timeout for Redis communication than the
#    default of 5 seconds
# :logger if you want the library to log activity as it works
##
# set_values() and inc_values() recieve Entry Objects array as params. Each Entry object
# has name,value and prefix attributes
# set_values() save value of database key to each Entry Object value with same "prefix+key" name
# inc_values() increment database values to a value with the same key of each Entry Object
# batch_command() build one-command-multiple-values request to Redis Database 
class StatToRedisInterface

  def initialize(params=Hash.new)
    @db = Redis.new(params)
    @semaphore = Mutex.new
  end
  
  def set_values(params=[])
    @semaphore.synchronize {
      batch_command(params){|commands,entry| commands[entry.prefix+entry.name] = entry.value}
    }
  end
  
  def inc_values(params=[])
    @semaphore.synchronize {
      batch_command(params){|commands,entry| commands.incr( entry.prefix+entry.name, entry.value)}
    }
  end
private
  def batch_command(params,&block)
    @db.pipelined do |commands|
      params.each do |entry|
        yield(commands,entry)
      end
    end
  end
  
end