= EMJack
An attempt to wrap portions of the Beanstalk protocol with EventMachine. Every command
will return a deferrable object. That object will succeed or fail depending on the 
reply returned from Beanstalk.

The current, default, errback is to print the error message received.

One thing to keep in mind. The Beanstalk protocol executes all commands serially.
So, if you send a reserve command and there are no jobs Beanstalk _won't_ process
any of the commands that come after the reserve until the reserve completes.

This is a bit of a gotcha when sending a series of reserve, delete, etc and there
are no available jobs.

= Dependencies
 - EventMachine
 - RSpec  (to run the tests)

= Examples
  EM.run {
    jack = EMJack::Connection.new
  
    r = jack.use('mytube')
    r.callback { |tube| puts "Using #{tube}" }
  
    r = jack.reserve
    r.callback do |job|
      puts job.jobid

      r2 = jack.delete(job) { puts "Successfully deleted" }
    end
  
    r = jack.put("my message", :ttr => 300) { |jobid| puts "put successful #{jobid}" }
  
    r = jack.stats
    r.callback { |stats| puts "Server up for #{stats['uptime']} seconds" }
    
    r = jack.stats(:tube, "mytube")
    r.callback { |stats| puts "Total jobs #{stats['total-jobs']}" }
    
    r = jack.list(:used)
    r.callback { |tubes| puts "There are #{tubes.length} tubes defined" }
  }

  Each of the Jack commands allows an optional block to be provided. If the block is given
  it will be setup as the callback on the deferrable.

  EMJack#each_job is useful for scenarios where the client is a job worker 
  and intended to process jobs continuously as they become available. Once 
  the queue is empty, the client will block and wait for a new job.

  If multiple workers connect to the queue Beanstalkd will round-robin between
  the workers.
    EM.run {
      jack = EMJack::Connection.new

      jack.each_job do |job|
        puts "Got job ##{job.jobid}: #{job}"

        if process(job)
          r = jack.delete(job)
          r.callback { puts "*Deleted #{job}*" }
        else
        end
      end

      def process(job)
        # Some kind of job processing
      end
    }


= Contact
If you've got any questions, comments or bugs, please let me know. You can
contact me by email at dj2 at everburning dot com.


= Contributors
Charles Melbye (cmelbye)
Peter Kieltyka (pkieltyka)
Martyn Loughran (mloughran)