Simple class to make it easy to send mail with Mandrill

mandrill_mailer.rb

require 'mandrill'

class MandrillMailer
  include SimpleStructuredLogger

  def self.mail(*args)
    self.new.mail(*args)
  end

  def mail(email:, template:, vars:)
    result = mandrill.messages.send_template(
      template,
      [],
      build_message(email, vars)
    )

    result = result.first

    if result['status'] != 'sent'
      fail "message failed to send: status=#{result['status']} reason=#{result['reject_reason']}"
    end

    log.info 'email sent',
      template: template,
      email: email,
      ns_order_id: vars['id']
  end

  private

    def mandrill
      @mandrill ||= Mandrill::API.new
    end

    def build_vars_for_mandrill(attributes)
      attributes.map do |key, value|
        {
          name: key,
          content: value
        }
      end
    end

    # TODO add first and last name for improved deliverability
    def build_message(email, vars)
      {
        to: [
          {
            "email": email,
            "type": "to"
          }
        ],
        merge_language: "handlebars",
        merge: true,
        global_merge_vars: build_vars_for_mandrill(vars),
      }
    end

end