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Question

So I'm using Delayed::Job workers (on Heroku) as an after_create callback after a user creates a certain model.

A common use case, though, it turns out, is for users to create something, then immediately delete it (likely because they made a mistake or something).

When this occurs the workers are fired up, but by the time they query for the model at hand, it's already deleted, BUT because of the auto-retry feature, this ill-fated job will retry 25 times, and definitely never work.

Is there any way I can catch certain errors and, when they occur, prevent that specific job from ever retrying again, but if it's not that error, it will retry in the future?

Answer 1

Abstract the checks into the function you call with delayed_job. Make the relevant checks wether your desired job can proceed or not and either work on that job or return success.

Answer 2

To expand on David's answer, instead of doing this:

def after_create
   self.send_later :spam_this_user
end

I'd do this:

# user.rb

def after_create
   Delayed::Job.enqueue SendWelcomeEmailJob.new(self.id)
end

# send_welcome_email_job.rb

class SendWelcomeEmailJob <  Struct(:user_id)
   def perform
      user = User.find_by_id(self.user_id)
      return if user.nil?  #user must have been deleted

      # do stuff with user
   end
end