Rails console DSL helpers

Hi there!

This is my first post on this blog. I decided to start to share some of my technical experience here. Well, let’s get started!

Problem

Working on a long-lived Rails project, we can face the situation of frequently using code snippets on the Rails console.

It can be some sort of context switching (for example, tenant switching or user switching) or some sort of tooling. It completely depends on your domain model and its technical implementation.

If you use gems like apartment for tenancy handling, your sessions on development or production console consist of constant switchings:

Aparment::Tenant.switch!('tenant_name_1')

# some tenant_name_1 job

Aparment::Tenant.switch!('tenant_name_2')

# some tenant_name_2 job

After hundreds and thousands of times of writing Apartment::Tenant...bla-bla phrases, you feel anger. And you want to reduce your keyboard activity.

Such a routine can be simplified with custom console helpers.

Solution

First, create a ruby class with the necessary methods:

module Ops
  module CustomRailsConsoleMethods
    def t(tenant_name)
      Aparment::Tenant.switch!(tenant_name)
    end
  end
end

Second, inform Rails about using this module on console:

# config/application.rb
console do
  Rails::ConsoleMethods.prepend(Ops::CustomRailsConsoleMethods)
end

Finally, we can simply use a shortened version of the command on the console:

t 'tenant_name_1'

# some tenant_name_1 job

t 'tenant_name_2'

# some tenant_name_2 job

Yay! Speed up!

Next steps

Name helpers in the logic of your domain

Just some ideas about the logic of tenant switching.

Names of methods:

• t - switch tenant
• tn - print current tenant name
• tl - list existing tenant names
• on_each_tenant - iterator over all tenants

Modify helpers according to your needs

The tenant switching method can apply some search patterns to arguments.

If you have the following list of tenant names:

• big_theatre
• maly_theatre
• sydney_opera

You can modify this switching method to use reduced arguments:

• t 'big'
• t 'mal'
• t 'syd'

Looks nice.

Think about naming conflicts

Sometimes your custom console helpers can conflict with other code. So you can save yourself from these conflicts with:

# ../ops/custom_rails_console_methods
if defined? t
  raise 'method `t` previously defined in code!'
else
  def t(tenant_name)
    Aparment::Tenant.switch!(tenant_name)
  end
end

Summary

Your development speed is a big value, so such workflow improvements like custom console helpers matter. Take care of your time.