Do something in a rake task before Rails models are loaded

Question

I have a rake task that works with models. But I need to tell the models that they are being used from Rake instead of within the app. My best idea is to set an environment variable on the command line before running the rake task, but that requires everyone on the team to remember to use the environment variable. Specifically, I have an if statement to skip loading Delayed::Job's handle_asynchronously while running the rake task.

class Thing < ActiveRecord::Base
  searchable do
    string :title
    text :title, :content
  end
  handle_asynchronously unless ENV['MIGRATINGDATA']
end

When we run our migration task we do this:

MIGRATINGDATA=true bundle exec rake project:migrate_data

I'd like to get rid of the need for the special addition to the command line. Our migration code loads a fake Sunspot instance to turn off indexing while migrating the data.

Answer 1

Just set something at the top of your Rakefile:

ENV['HELLO_RAKE'] = true

require_relative 'config/application'

Rails.application.load_tasks

Instead of using ENV you could, if you wanted, set a constant, e.g. HELLO_RAKE = true and then check defined?(HELLO_RAKE).

An alternative is to just check if the running program is rake:

handle_asynchronously unless File.basename($0) == "rake"

A downside to both of these approaches is that they will be in effect any time you're using Rake, which will include other Rake tasks not related to migrations.