Native Pub/Sub in Rails with ActiveSupport::Notifications

If you want to use pub/sub design pattern inside your rails app, there's no need to add extra dependencies, you can use ActiveSupport::Notifications to do the job

Example:

class Order
  # methods

  def complete
    update(complted_at: Time.zone.now, etc: 'some')
    ActiveSupport::Notifications.instrument("order_completed", { number: order.number })
  end
end

module Subscribers
  class SendConfirmationEmail
    def self.subscribe!
      ActiveSupport::Notifications.subscribe("order_completed") do |_name, _start, _finish, _id, params|
        order = Order.find_by number: params[:number]
        OrderMailer.confirm_order(order).deliver_later
      end
    end
  end
end

module Subscribers
  class UpdateCustomerCRM
    def self.subscribe!
      ActiveSupport::Notifications.subscribe("order_completed") do |_name, _start, _finish, _id, params|
        order = Order.find_by number: params[:number]
        CrmIntegration.update_customer(order.customer.email, order.total_amount)
      end
    end
  end
end

# etc