gistfile1.rb

# I use nateware/redis-objects as an easy way to implement atomic counters in my ActiveRecord models in Rails.
# But I still need counters in sql to sort models with them.

# So the CounterSyncWorker goes through the object space, selects all class that is an AR model and includes Redis::Objects,
# check for all columns that have _sql equivalents, fetches the value in redis and store into the AR attribute.

# Example:

# when uploading a photo that belongs to first user:

# user = User.first
# photo = user.photos.create
# user.photo_count # 1
# user.photo_count_sql # 0

# After scheduled counter_sync,

# user = User.first
# user.photo_count # 1
# user.photo_count_sql # 1

class CounterSyncWorker
  include Sidekiq::Worker
  sidekiq_options queue: "counter_sync"
  
  def perform()
    #http://stackoverflow.com/questions/2393697

    #select models with counters
    models = ObjectSpace.each_object(Class).select
      { |klass| klass < ActiveRecord::Base && klass.included_modules.include?(Redis::Objects) } 
    models.each do |model|
      columns = model.columns_hash.keys
      sql_counts =  model.columns_hash.keys.select { |s| s.include?('_sql') }
      if sql_counts.count > 0
        model.all.each do |instance|
          sql_counts.each do |sql_count|
            instance.send("#{sql_count}=", instance.send(sql_count[0..-5]).to_i)
          end
          instance.save
        end
      end
    end

    self.class.perform_in(30.minutes)
  end
end