How to send emails with ActionMailer and Sidekiq

action_mailer_and_sidekiq.md

Sending emails with ActionMailer and Sidekiq

Send email asynchroniously using Sidekiq.

ActionMailer

Create mailer class:

# app/mailers/user_mailer.rb

class UserMailer < ActionMailer::Base

  def welcome_email(user_id)
    @user = User.find(user_id)

    mail(to: @user.email, subject: "Hola")
  end
end

Views for email:

app/views/user_mailer/welcome_email.html.erb - HTML version
app/views/user_mailer/welcome_email.text.erb - TEXT version

Send email:

user = User.find(1)

UserMailer.welcome_email(user.id).deliver_later    

SMTP Settings

# config/environments/development.rb

Rails.application.configure do 
  config.action_mailer.delivery_method = :smtp
  
  config.action_mailer.smtp_settings = {
    address: 'localhost',
    port: 1025
  }
end

For production

# config/environments/production.rb

Rails.application.configure do 
  config.action_mailer.delivery_method = :smtp
  
  config.action_mailer.smtp_settings = {
    domain: ENV['MAILGUN_DOMAIN'],
    address: ENV['MAILGUN_HOST'],
    user_name: ENV['MAILGUN_USERNAME'],
    password: ENV['MAILGUN_PASSWORD'],
    port: ENV["MAILGUN_PORT"]
  }
end

Sidekiq

Gemfile:

gem 'sidekiq'

Install Redis

Redis provides data storage for Sidekiq. It holds all the job data along with runtime and historical data

Configure Sidekiq

To make #deliver_later work we need to tell ActiveJob to use Sidekiq. As long as Active Job is setup to use Sidekiq we can use #deliver_later.

# config/initializers/active_job.rb

config.active_job.queue_adapter = :sidekiq

Read more about ActionJob and Sidekiq in the docs.

Configure Sidekiq

By default, jobs to deliver emails will be placed in queue named :mailers.

config/sidekiq.yml:

---
:concurrency: 1
:queues:
  - default
  - mailers

Specify Redis namespace for different environments:

# config/initializers/sidekiq.rb

Sidekiq.configure_server do |config|
  config.redis = { url: ENV["REDIS_URL"] }
end

Sidekiq.configure_client do |config|
  config.redis = { url: ENV["REDIS_URL"] }
end

Run Sidekiq

bundle exec sidekiq