Send email by action mailer

_actionmailer

send_email.rb
mailer/
  |- daily_email.html.erb
  |- daily_email.text.erb

daily_email.html.erb

<%# path: ./mailer/daily_email.html.erb %>

<h1>Hello <%= @name %>!</h1>

<p>
  Welcome to our system.
</p>

daily_email.text.erb

<%# path: ./mailer/daily_email.text.erb %>

Hello <%= @name %>!

Welcome to our system.

send_email.rb

require 'bundler/inline'

# dependencies
gemfile do
  source 'https://rubygems.org'

  gem 'actionmailer', '4.2.9'

  # it is needed in ruby 3.x
  gem 'net-smtp', require: false
  gem 'net-imap', require: false
  gem 'net-pop', require: false
end

require 'action_mailer'

# config
ActionMailer::Base.raise_delivery_errors = true
ActionMailer::Base.delivery_method = :smtp
ActionMailer::Base.view_paths = File.dirname(__FILE__)

ActionMailer::Base.smtp_settings = {
  address:        ENV.fetch('SMTP_HOST'),
  port:           ENV.fetch('SMTP_PORT'),
  user_name:      ENV.fetch('SMTP_EMAIL'),
  password:       ENV.fetch('SMTP_PASSWORD'),
  domain:         'yoursite.com',
  authentication: 'login'
}

# code
class Mailer < ActionMailer::Base
  def daily_email
    @name = 'Wallas Faria'

    mail(from: 'from@email.com', to: 'to@email.com', subject: 'testing mail') do |format|
      format.text
      format.html
    end
  end
end

# main
email = Mailer.daily_email
puts email
email.deliver_now