Mail::SMTPPool

This gem is an extension to Mail that allows delivery of emails using an SMTP connection pool

Installation

Add this line to your application's Gemfile:

gem 'mail-smtp_pool'

And then execute:

bundle

Or install it yourself as:

gem install mail-smtp_pool

Usage with ActionMailer

# config/environments/development.rb

Rails.application.configure do
  ...

  ActionMailer::Base.add_delivery_method :smtp_pool, Mail::SMTPPool

  config.action_mailer.perform_deliveries = true
  config.action_mailer.smtp_pool_settings = {
    pool: Mail::SMTPPool.create_pool(
      pool_size:            5,
      pool_timeout:         5,
      address:              'smtp.gmail.com',
      port:                 587,
      domain:               'example.com',
      user_name:            '<username>',
      password:             '<password>',
      authentication:       'plain',
      enable_starttls_auto: true
    )
  }
end

Configuration options:

• pool_size - The maximum number of SMTP connections in the pool. Connections are created lazily as needed.
• pool_timeout - The number of seconds to wait for a connection in the pool to be available. A Timeout::Error exception is raised when this is exceeded.

This also accepts all options supported by Mail::SMTP. See https://www.rubydoc.info/gems/mail/2.6.1/Mail/SMTP for more information.