dj_migrate_format.rb

require 'active_record'

# Migrating from http://github.com/tobi/delayed_job to http://github.com/collectiveidea/delayed_job
# and with some jobs pending resulted in execution failure due to handler format incompatibility.
#
# This rake task loops through your delayed_jobs table and updates the handler of each job to comply with
# collectiveidea's delayed_job.
#
# Hope this can be useful to someone.
# 
# Convert
#
# http://github.com/tobi/delayed_job
# Job handler format:
#
# --- !ruby/struct:Delayed::PerformableMethod 
# object: CLASS:Notifier
# method: :deliver_activation_confirmation
# args: 
# - AR:User:20
#
# to
#
# http://github.com/collectiveidea/delayed_job
# Job handler format:
#
# --- !ruby/struct:Delayed::PerformableMethod 
# object: !ruby/class Notifier
# method: :deliver_activation_confirmation
# args: !ruby/ActiveRecord:User 
#   attributes: 
#     id: "20"
#     created_at: 2009-04-03 01:12:28
#     state: active
#     etc ...

namespace :dj_migrate_format do

  task :start_task => :environment do

    Delayed::Job.all.each do |job|

      handler_yaml = YAML.load(job.handler)

      object = handler_yaml[:object].split(":")[1].constantize
      method = handler_yaml[:method]

      args_model = handler_yaml[:args].first.split(":")[1]
      args_id = handler_yaml[:args].first.split(":")[2]
      args = args_model.constantize.find args_id

      new_handler = Delayed::PerformableMethod.new object, method, args
      new_handler_yaml = new_handler.to_yaml

      job.handler = new_handler_yaml
      job.save
    end
  end
end