run-some-code-whenever-rails-console-starts.md

Run Some Code Whenever Rails Console Starts

It can be handy to run some code whenever the rails console command is run. You may want to have some modules required, some variables set up, or, both fancy and practical, default to the read replica database in production.

Rails provides a hook into the console startup with the console block in config/application.rb.

Here is what it looks like to puts out the environment:

class Application < Rails::Application
  # everything else ...

  console do
    puts '############################################'
    puts 'Connected to the #{Rails.env.upcase} console'
    puts '############################################'
  end
end

To avoid cluttering config/application.rb with a bunch of console-specific logic, you can move it to another file and then have the console block require that file with the -r flag.

class Application < Rails::Application
  console do
    ARGV.push "-r", Rails.root.join("lib/console.rb")
  end
end

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