persistable delayed tasks in ruby on rails

Question

I am running a ruby on rails application, and as part of a certain process, i need to send a mail to a user after 10 minutes from a certain operation if a specific condition occurs.

I saw that a gem called rufus can be used to implement this ( https://github.com/jmettraux/rufus-scheduler/blob/two/README.rdoc ), and it looks great to just do something like :

scheduler.in '3s' do puts 'Hello... Rufus' end

from what i understand, it runs in a background in-process in-memory thread and fires the proc at a desired time. But, from what I understood, it is not persistent which creates a big problem for us, since we continuously deploy, and a deploy will kill the existing process thus killing the thread and the desired action to occur.

Can someone suggest a working approach for this, maybe another framework that supports persistence or maybe use an existing gem with some tweaks?

thanks a lot, Alex

Answer 1

Use sidekiq, it's basically a job queue and persists jobs into a Redis DB, also has a nice web interface, retries etc. etc.

For running scheduled jobs take a look at https://github.com/mperham/sidekiq/wiki/Scheduled-Jobs

YourAfterJobWorker.perform_in 10.minutes, user.id

The implementation of your worker would look like

# app/workers/your_after_job_worker.rb
class YourAfterJobWorker
  include Sidekiq::Worker

  def perform(user_id)
    user = User.find(user_id)
    TheAfterJobMailer.some_email(user).deliver if user.matches_your_condition?
  end
end

Answer 2

If you don't want another operational dependency (Sidekiq requires Redis), there's always DelayedJob which works with a new table in your SQL environment (they support other backends now too), albeit less efficiently than Sidekiq/Redis.

The syntax is nearly identical to Sidekiq and other ActiveJob implementations.