A cron job for rails: best practices?

I've used the extremely popular Whenever on projects that rely heavily on scheduled tasks, and it's great. It gives you a nice DSL to define your scheduled tasks instead of having to deal with crontab format. From the README:

Whenever is a Ruby gem that provides a clear syntax for writing and deploying cron jobs.

Example from the README:

every 3.hours do  runner "MyModel.some_process"         rake "my:rake:task"                   command "/usr/bin/my_great_command"endevery 1.day, :at => '4:30 am' do   runner "MyModel.task_to_run_at_four_thirty_in_the_morning"end

I'm using the rake approach (as supported by heroku)

With a file called lib/tasks/cron.rake ..

task :cron => :environment do  puts "Pulling new requests..."  EdiListener.process_new_messages  puts "done."end

To execute from the command line, this is just "rake cron". This command can then be put on the operating system cron/task scheduler as desired.

Update this is quite an old question and answer! Some new info:

• the heroku cron service I referenced has since been replaced by Heroku Scheduler
• for frequent tasks (esp. where you want to avoid the Rails environment startup cost) my preferred approach is to use system cron to call a script that will either (a) poke a secure/private webhook API to invoke the required task in the background or (b) directly enqueue a task on your queuing system of choice

In our project we first used whenever gem, but confronted some problems.

We then switched to RUFUS SCHEDULER gem, which turned out to be very easy and reliable for scheduling tasks in Rails.

We have used it for sending weekly & daily mails, and even for running some periodic rake tasks or any method.

The code used in this is like:

    require 'rufus-scheduler'    scheduler = Rufus::Scheduler.new    scheduler.in '10d' do      # do something in 10 days    end    scheduler.at '2030/12/12 23:30:00' do      # do something at a given point in time    end    scheduler.every '3h' do      # do something every 3 hours    end    scheduler.cron '5 0 * * *' do      # do something every day, five minutes after midnight      # (see "man 5 crontab" in your terminal)    end

To learn more: https://github.com/jmettraux/rufus-scheduler