A cron job for rails: best practices?

What's the best way to run scheduled tasks in a Rails environment? Script/runner? Rake? I would like to run the task every few minutes.

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• the heroku cron service I referenced has since been replaced by Heroku Scheduler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