Rails Quick Tip - 04 - Automating Code with Rake Tasks

Ruby on Rails uses a Ruby gem called rake to generate tasks that otherwise enable your applications to call code with alias commands.

This Rails quick tip walks you through what a rake task looks like and how the Ruby on Rails framework leverages them directly for automating code.

Generating your first task

Rails ships with multiple generators that are accessible via the command line. The idea behind generators is to reduce the need to manually create files and some boilerplate code each time you need it.

You can see a list of all the generators available for your app by running the following:

rails generate

This should list a bunch of options. Depending on what gems you have installed, there may be a suite of custom options available alongside what comes stock with Rails.

One of the generators included in the framework is called task.

To generate a new task, you can run this code:

rails generate task my_new_task

Typically your task should describe its intended use case, but as most software people know, naming things is one of the most complex challenges in programming, so do your best here.

A vanilla task file won't have much code inside it. You can namespace the task for best results, so it's easily recognizable from the command line. Including a description is recommended to help let other contributors know what purpose the task serves.

As an example, I generated a new update_users task by running:

rails g task update_users

The file's name isn't the best, but the general idea is I'm updating something related to a user model. Inside the task, you can write logic that you would like to automate.

# lib/tasks/update_users.rake
namespace :users do
  desc "Update users on the nightly"
  task update: :environment do
    puts "Hello world"
  end
end

Previewing what tasks are available

An excellent way for others to know what rake tasks exist for a specific Rails app is through a new command.

rails --tasks

This lists all available tasks. Luckily, our new task should be listed, including the description we set.

Why use rake tasks with Rails?

This will vary depending on your app, but I use rake tasks to automate repetitive things.

If you can write a task to call a rake command using some service like Heroku scheduler or a gem like Whenever, you can take a lot of time back and likely deliver a richer experience for your end users.

Rake tasks can be used for something as simple as a boolean toggle to something more complex, like database migrations or API calls to backfill data.