Logical Friday

Consider a fairly normal pattern in a user model in Rails, sending a welcome email when a user signs up. If you’re interested in keeping your controller actions quick whilst you do this, you would probably queue the email to be sent later, like this:

class User < ActiveRecord::Base
  
  after_save :queue_welcome_email, :on => :create
  private
  def queue_welcome_email
    Resque.enqueue(WelcomeEmailJob, self.id)
  end
end

class WelcomeEmailJob
  @queue = :normal

  def self.perform(user_id)
    user = User.find(user_id)
    UserMailer.welcome_email(user).deliver
  end
end

Straightforward, right? You’d think so, but if you implemented this and ran it in a live system, you would find a small number of ActiveRecord::RecordNotFound errors cropping up in Resque.

« Read the rest of this entry »