Is Rails's "delayed_job" for cron task really?

Question

delayed_job is at http://github.com/collectiveidea/delayed_job

Can delayed_job have the ability to do cron task? Such as running a script every night at 1am. Or run a script every 1 hour.

If not, what are the suitable gems that can do that? And can it be monitored remotely using a browser, and have logging of success and error?

Answer 1

I think cron is a better tool for this than delayed_job. I've used it in a project before, and it really excels at running at task in the background or at a particular time. But, for recurring tasks that happen at regular times, I think cron is the best tool.

Check out whenever (and its Railscast) to easily schedule cron jobs that can run rake tasks (or thor, or shell scripts, or anything else.) You can use the rake tasks to update your models and then have some sort of dashboard controller that looks at the various statuses.

Answer 2

I worked on a project that tried to use DelayedJob to schedule future items. It sucked.

Instead I recommend you use the whenever gem:

http://github.com/javan/whenever

Whenever is a Ruby gem that provides a clear syntax for defining cron jobs. It outputs valid cron syntax and can even write your crontab file for you. It is designed to work well with Rails applications and can be deployed with Capistrano. Whenever works fine independently as well.

Code looks like this (from github)

  every 3.hours do
    runner "MyModel.some_process"
    rake "my:rake:task"
    command "/usr/bin/my_great_command"
  end

  every 1.day, :at => '4:30 am' do
    runner "MyModel.task_to_run_at_four_thirty_in_the_morning"
  end

  every :hour do # Many shortcuts available: :hour, :day, :month, :year, :reboot
    runner "SomeModel.ladeeda"
  end

  every :sunday, :at => '12pm' do # Use any day of the week or :weekend, :weekday
    runner "Task.do_something_great"
  end

Here's a RailsCast video on how to use it.

And the corresponding ASCIICast.

Answer 3

Whenever works great.

I also like rufus-scheduler

/config/initializers/task_scheduler.rb

scheduler = Rufus::Scheduler.start_new  

scheduler.every("1m") do  
   DailyDigest.send_digest!  
end 

I originally found this posted here

I've tried it and it works well.

Answer 4

I run multiple cron delayed_jobs for nightly statistic and report generating and also for data scrapping at certain intervals. Here's how I do it:

http://aaronvb.com/blog/2010/10/27/recurring-delayed_job-with-cron