skip_callbacks.rb

require 'active_record'

ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: 'db.sqlite3')

ActiveRecord::Schema.define do
  create_table :users, force: true do |t|
  end
end

class ActiveRecord::Base
  cattr_accessor :skip_callbacks
end

class User < ActiveRecord::Base
  after_create :send_greeting_email, unless: :skip_callbacks

  private

  def send_greeting_email
    puts 'Sending greeting email..'
  end
end

ActiveRecord::Base.skip_callbacks = true
User.create
# => Sending greeting email..
ActiveRecord::Base.skip_callbacks = false
User.create
# Will output nothing