Every Web Application Needs a Background Processing Queue

External Services

Many tasks that rely on external services are also suitable for running as background jobs. Sending a confirmation email, storing a photo, creating a thumbnail, or posting to social media platforms are jobs that don’t need to be run in the front end of the web page response. The controller in the application can put the email, image processing, or social media post job into a delayed job queue, then return control to the user as quickly as possible.

Using a background process to send an email to a customer means less waiting around for that customer, and a boost to your business’s brand reputation. As IronWorker uses Docker containers, you could use any programming language you wanted for this. This example shows one way to set up sending an email as a background task using the open-source programming language, Ruby.

The first step is to create a Gemfile in a new directory, and input the following:

source 'https://rubygems.org'

gem 'sendgrid-ruby'

gem 'iron_worker', '>= 3.0.0'

You can then create a Ruby file, send_email.rb, that will send emails as a background task for you:

require_relative 'bundle/bundler/setup'

require 'iron_worker'

require 'sendgrid-ruby'

include SendGrid

from = Email.new(email: IronWorker.payload["from"])

to = Email.new(email: IronWorker.payload["to"])

subject = IronWorker.payload["subject"]

content = Content.new(type: 'text/plain', value: IronWorker.payload["body"])

mail = Mail.new(from, subject, to, content)

sg = SendGrid::API.new(api_key: ENV['SENDGRID_API_KEY'])

response = sg.client.mail._('send').post(request_body: mail.to_json)

puts response.status_code

puts response.body

puts response.headers

Now it’s time to create a payload.json file. This contains the actual data that gets sent to the Ruby program.

{

"from": "test@example.com",

"to": "you@example.com",

"subject": "It works!",

"body": "Hello from IronWorker"

}

The next step is installing the dependencies using Docker, zipping up the code, and uploading it to Iron.

This example uses a Ruby-based Docker image from Iron.io itself, to make things simpler. More experienced developers can use their own images or source images elsewhere, like Docker hub.

> docker run --rm -v "$PWD":/worker -w /worker iron/ruby:dev bundle install --standalone --clean

> zip -r email_worker.zip .

> iron worker upload -e SENDGRID_API_KEY=YOUR_SENDGRID_API_KEY --name email_worker --zip email_worker.zip iron/ruby ruby send_email.rb

This code, once uploaded to Iron, works with IronWorker to send email whenever required. The instruction o run the task could be as follows:

> iron worker queue --payload-file payload.json --wait email_worker

Tasks such as these are not limited by email server or provider, and will work on any system or in any environment thanks to the Docker architecture.