{"id":5664,"date":"2017-06-19T18:21:45","date_gmt":"2017-06-20T01:21:45","guid":{"rendered":"https:\/\/www.backerkit.com\/blog\/?p=5664"},"modified":"2020-02-21T00:40:59","modified_gmt":"2020-02-21T08:40:59","slug":"building-and-deploying-ruby-docker-images-with-circleci-and-heroku","status":"publish","type":"post","link":"https:\/\/www.backerkit.com\/blog\/building-and-deploying-ruby-docker-images-with-circleci-and-heroku\/","title":{"rendered":"Building and Deploying Ruby Docker Images with CircleCI and Heroku"},"content":{"rendered":"

Heroku makes it dead simple to deploy and operate apps; Docker makes it even easier! Heroku has a Docker runtime<\/a> in beta.<\/p>\n

This article will review how to setup a simple Ruby app to build and deploy as a Docker container on Heroku using CircleCI<\/a>.<\/p>\n

The app we’ll be using<\/h2>\n

We run a dashboard for internal use with a range of widgets that give us data about various events in the company and application. We use Smashing<\/a>, which is a Sinatra-esque Ruby framework for building dashboards.<\/p>\n

Setting up the Dockerfile<\/h2>\n

Heroku recently released their new Heroku-16<\/a> stack. We’ll base our image off it. We’ll then install required system dependencies so we can install gems. Next we’ll install bundler<\/code> and our gem dependencies. From there we’ll give the container a default CMD<\/code> that will boot up the dashboard.<\/p>\n

FROM heroku\/heroku:16\n\nRUN apt-get update -qq && apt-get install -y \\\n  build-essential \\\n  libpq-dev \\\n  nodejs \\\n  ruby-dev\nRUN mkdir \/my_dashboard\nWORKDIR \/my_dashboard\nADD Gemfile \/my_dashboard\/Gemfile\nADD Gemfile.lock \/my_dashboard\/Gemfile.lock\nRUN gem install bundler\nRUN bundle install\nADD . \/my_dashboard\nCMD rackup --port=$PORT\n<\/code><\/pre>\n
In order to build this image, we’ll need to install Docker. Assuming we’re on Mac, we’ll head over here<\/a> to install Docker. Once we’ve installed Docker, we’ll cd<\/code> into the project directory and run the following commands:<\/p>\n
docker build . -t my_dashboard\ndocker run -p 9292:9292 my_dashboard rackup\n<\/code><\/pre>\n
Now we should have the app up and running!<\/p>\n
If everything looks good, deploy the image manually to Heroku using the following commands.<\/p>\n
heroku plugins:install heroku-container-registry\nheroku container:login\nheroku container:push\nheroku open\n<\/code><\/pre>\n
Our dashboard is alive on Docker!<\/p>\n
Building and deploying via CI<\/h2>\n
We want to be able to deploy our app from our continuous integration system instead of pushing manually. We’ll use CircleCI.<\/p>\n
Add a circle.yml<\/code> file to our project with the following config.<\/p>\n
machine:\n  services:\n    - docker\n\ndependencies:\n  override:\n    - echo \"no deps\"\n\ntest:\n  post:\n    - echo \"yay - no tests\"\n\ndeployment:\n  production:\n    branch: master\n    commands:\n      - docker build -t my_dashboard .\n      - docker login --email=_ --username=_ --password=$HEROKU_TOKEN registry.heroku.com\n      - docker tag my_dashboard:latest registry.heroku.com\/my_dashboard\/web\n      - docker push registry.heroku.com\/my_dashboard\/web\n<\/code><\/pre>\n
We’ll need to configure an environment variable for HEROKU_TOKEN<\/code> (taken from our Heroku dashboard) so Circle can authenticate against the Heroku container registry.<\/p>\n
Upon the next successful master<\/code> build, we should see our image be built and then deployed to Heroku all from CI!<\/p>\n
Open questions<\/h2>\n
Working with Docker raises some open questions around developer workflow, especially for more complicated applications (e.g. those with a separate worker process).<\/p>\n
Here are some of the issues:<\/p>\n