# Terminal
bundle exec sidekiq -C config/sidekiq.yml

# app/events/application_publisher.rb
class ApplicationPublisher
  include Wisper::Publisher
  def self.call(*args)
    new(*args).call
  end
end

# app/events/publishers/user_created.rb
class Publishers::UserCreated < ApplicationPublisher
  attr_accessor :user_id
  def initialize(user_id)
    @user_id = user_id
    subscribe(Subscribers::UserCreated, async: true)
  end

  def call
    user = User.find_by(id: user_id)

    if user.email?
      publish(:welcome_user_email, user.id)
      # broadcast(:welcome_user_email, user.id)
    end
  end
end

# app/events/subscribers/user_created.rb
class Subscribers::UserCreated
  def self.sidekiq_options
    { queue: 'first_service_app' }
  end

  # If you're not running the event in a background task
  # then the method would be an instance method.
  # def welcome_user_email(user_id)
  # end

  def self.welcome_user_email(user_id)
    # send email
  end
end

# users_controller.rb
  def create
    @user = User.new(user_params)

    respond_to do |format|
      if @user.save
        Publishers::UserCreated.call(@user.id)
        format.html { redirect_to @user, notice: 'User was successfully created.' }
        format.json { render :show, status: :created, location: @user }
      else
        format.html { render :new }
        format.json { render json: @user.errors, status: :unprocessable_entity }
      end
    end
  end

# Gemfile
gem 'wisper'
gem 'sidekiq'
gem 'wisper-sidekiq'

# config/routes.rb
require 'sidekiq/web'
Rails.application.routes.draw do
  resources :users
  root to: 'users#index'
  mount Sidekiq::Web => '/sidekiq'
end

# config/application.rb
config.active_job.queue_adapter = :sidekiq

# config/sidekiq.yml
:queues:
  - first_service_app