Sidekiq Mail MJML Prototype

Barebones prototype for sending MJML/ERB emails using Sidekiq via a simple Sinatra API.

Requirements

• Redis must be installed and running.
• Node.js and MJML must be installed.
• Obviously, Ruby must be installed. ;)
• An SMTP server or service available for sending email messages.

Prototype Configuration

There are a few parameters that need to be configured for the prototype to work.

Sidekiq / Redis

Add and edit a sidekiq.env file with the Redis host, port and db.

export REDIS_HOST=localhost
export REDIS_PORT=6379
export REDIS_DB=YOUR_REDIS_DB

Additional Sidekiq configuration changes can be made to the config/sidekiq.rb file:

# config/sidekiq.rb

Sidekiq.configure_server do |config|
  config.redis = { :host => ENV['REDIS_HOST'], :port => ENV['REDIS_PORT'], :db => ENV['REDIS_DB'] }
end

Sidekiq.configure_client do |config|
  config.redis = { :host => ENV['REDIS_HOST'], :port => ENV['REDIS_PORT'], :db => ENV['REDIS_DB'] }
end

MJML

Once Node.js is installed, you can install MJML:

> npm install -g mjml

Edit the config/mjml.rb file with the MJML binary path, the validation level and any other available parameter.

# config/mjml.rb

MJML.configure do |config|
  # Make sure that MJML is installed and that the proper binary path is configured.
  # Could not make the following config work: 
  # config.bin_path = '/usr/bin/env mjml'
  config.bin_path = '/usr/local/bin/mjml'
  # config.logger = MJML::Logger.setup!(STDOUT)
  config.minify_output = true
  # Set the validation level to :strict if you want to have MJML v3.0 validation.
  config.validation_level = :strict # :skip/:soft/:strict
end

Mail / SMTP

The prototype has been tested using Amazon Simple Email Service (SES). The mail.env and config/mail.rb can be modified/tweaked for other email services.

Add and edit a mail.env file with the SMTP server, port, username, password and sender email:

export MAIL_SMTP_SERVER=your.smtp.server.com
export MAIL_SMTP_PORT=587
export MAIL_SMTP_USERNAME=YOUR_IAM_SMTP_USER_FOR_SES
export MAIL_SMTP_PASSWORD=YOUR_VERY_LONG_PASSWORD
export [email protected]

Additional Mail configuration changes can be made to the config/mail.rb file:

# config/mail.rb

Mail.defaults do
  # These settings have been tested with AWS SES.
  # Settings may need to be tweaked for Gmail, AWS WorkMail, and other services.
  smtp_settings = { :address   => ENV['MAIL_SMTP_SERVER'],
                    :port      => ENV['MAIL_SMTP_PORT'],
                    :user_name => ENV['MAIL_SMTP_USERNAME'],
                    :password  => ENV['MAIL_SMTP_PASSWORD'],
                    :authentication => 'plain',
                    :enable_starttls_auto => true }
  delivery_method :smtp, smtp_settings
end

Running the Prototype

1. Run bundle install to get all the gems needed by the prototype.

2. Make sure that Redis is running. Redis can be started by running:

> redis-server

3. Start Sidekiq by running:

> sidekiq -r ./sidekiq_server.rb

4. Start the Sinatra application by running:

> rackup config.ru

5. Assuming that Sinatra is listening on http://localhost:9292/, make a POST request to the /send resource with the following parameters:

   • rcpt - The email message recipient.
   • subj - The email message subject.
   • msg - The email message content.

   Postman is your friend! You can make a POST request and send the data via parameters or form-data.