How can I schedule a 'weekly' job on Heroku?

Question

I have a Rails app deployed on Heroku with the Heroku scheduler add-on successfully working for daily jobs.

Now I want a weekly job, but the schedul

Answer 1

It's not ideal, but I've taken to adding a RUN_IF environment variable to rake tasks run through heroku:scheduler which lets me weekly and monthly schedules for jobs.

# lib/tasks/scheduler.rake
def run?
  eval ENV.fetch('RUN_IF', 'true')
end

def scheduled
  if run?
    yield
  else
    puts "RUN_IF #{ENV['RUN_IF'].inspect} eval'd to false: aborting job."
  end
end

# lib/tasks/job.rake
task :job do
  scheduled do
    # ...
  end
end

If a rake task is run without a RUN_IF variable it will run. Otherwise, the job will be aborted unless the value of RUN_IF evals to a falsey value.

$ rake job                              # => runs always
$ rake job RUN_IF='Date.today.monday?'  # => only runs on Mondays
$ rake job RUN_IF='Date.today.day == 1' # => only runs on the 1st of the month
$ rake job RUN_IF='false'               # => never runs (not practical, just demonstration)

Similar to other ideas above, but I prefer moving the scheduling details out of the application code.