<riveting introduction drawing you into the blog followed by useless facts about facebook’s growth and reach that you won’t remember five minutes after leaving this page>

<mild segue discussing the power of facebook’s new open graph API>

<well balanced discussion indicating target audience of rails developers and all the power derived therein>

<short intro to facebooker2 and mogli>

<link to my facebooker2 fork on github.. oh wait. you really need that.>

http://github.com/wallace/facebooker2

Steps I had to take on the git repos:

verify that rake version is 0.8.4 and rubygems is 1.3.1
rm -rf vendor/rails
gem update rails rack
cd vendor && git clone git://github.com/rails/rails.git
cd rails && grb track 2-3-stable
git checkout 2-3-stable
rm -rf .git
cd ~/
modify environment.rb to user rails 2.3.2
rake rails:update
git add -A

Upgrade issues I ran into:

# check plugins/gems that need to be updated
# mocha
5076 rollbook:master+! % rake test:units
rake aborted!
can't activate mocha (= 0.9.4, runtime), already activated mocha-0.9.5
# move "require 'mocha'" from test/test_helper.rb into config/environments/test.rb
# http://gist.github.com/111060 -- solution: remove "require 'ar-extensions" from config/initializers/.rb
# remove all references to Test::Unit http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/f90ecdba834c2ef8/f204e834e5e0303c?lnk=raot in test dir
# replace Test::Unit w/ActiveRecord or ActionController as appropriate
# replace CGI::Session.generate_unique_id w/ActiveSupport::SecureRandom.hex(16)
# updated hoptoad and shoulda
# add xmlsimple to be required
# updated new_relic agent
# install country_select plugin

Steps to be take on the production server:

# update passenger 2.2.2
# gem update rails rack

The other day on our staging server, I noticed that the BackgrounDRb queue worker had died. As it turned out, the queue worker had died over 3 months ago!!

There was no cause for alarm as the staging server isn’t critical but this did start me to worrying. We needed to implement a monitoring solution which not only verified that BackgrounDRb was running but also that particular workers were running.

As we had just implemented god monitoring with a custom condition for another issue, its a slam dunk to do the same again. (Thanks to Jesse Newland and his god tutorial at AtlRUG.)

Here’s the configuration file that got it done for us.

#run on command line with 'god -c backgroundrb.god -D'
RAILS_ROOT = '/var/www/rails/rollbook/current'

#load required rails and backgroundrb files
require File.dirname(__FILE__) + '/../boot'
require File.dirname(__FILE__) + '/../environment'
require 'erb'
$LOAD_PATH << "#{RAILS_ROOT}/vendor/plugins/backgroundrb/lib"
require "#{RAILS_ROOT}/vendor/plugins/backgroundrb/lib/backgroundrb.rb"

#create custom condition for checking that QueryProcessingWorker is running
MiddleMan = BackgrounDRb::ClusterConnection.new
module God
  module Conditions
    class Backgroundrb < PollCondition
      def initialize; super; end
      def valid?; true; end 

      def test
        begin
          queue_worker = MiddleMan.all_worker_info.values.flatten.select { |w| :queue_processing_worker == w[:worker] }
          queue_worker.empty?
        rescue #if all_worker_info raises exception, then bdrb isn't running and we were unable to connect
          true
        end
      end
    end
  end
end

God.watch do |w|
  w.name      = 'backgroundrb'
  w.interval  = 1.minute
  w.restart   = "cd #{RAILS_ROOT} && #{RAILS_ROOT}/script/backgroundrb -e production stop && #{RAILS_ROOT}/script/backgroundrb -e production start"
  w.stop      = "cd #{RAILS_ROOT} && #{RAILS_ROOT}/script/backgroundrb -e production stop"
  w.start     = "cd #{RAILS_ROOT} && #{RAILS_ROOT}/script/backgroundrb -e production start"
  w.grace     = 1.minute
  w.pid_file  = "#{RAILS_ROOT}/tmp/pids/backgroundrb_11000.pid"

  w.start_if do |start|
    start.condition(:process_running) do |c|
      c.running  = false
    end
  end 

  w.restart_if do |restart|
    restart.condition(:backgroundrb) do |c|
      #just restart it
    end
  end
end 

In the select call on line 21, you can modify the condition to access :job_key or :status as well. Obviously, you need to modify RAILS_ROOT for your situation.

If you have suggestions for improvement or questions, hit me up in the comments. Enjoy!

There’s two ways to install listed over at ack; I chose the CPAN route (since I never know when I’ll need to install some more perl goodies).

How to install ack on Mac OS X leopard in 3 easy steps.

1. install mac ports
2. sudo port install perl5.8
3. sudo cpan -i App::Ack