eddiewebb / circleci-challenge

Spring Boot deployed using circleci for blue/green deployment to Cloud Foundry

Circle CI Challenge

Build, Test and Deploy a simple webapp using CircleCI and Heroku.

Testing

To test simple UI functionality we're using Spring Boot's test starter and SauceLabs Connect Tunnel binaries driven through Selenium's WebDriver interface.

You can see these simple tests in HomePagesTests.java

Deploying

This project deploys on two common PaaS providers; Heroku and Pivotal Web Services (Cloud Foundry).

Heroku

This was my first time using Heroku, and have more experience with Cloud Foundry as an abstracted application PaaS. I disliked the idea of Heroku rebuilding deployable from source, being a firm believer in "Build once, run anywhere."

Since spring boot creates a self-contained runnable jar, that the tests above validate, it was important to find a non git push way to deploy this project in which only the precompiled artifact was passed. And in fact the Heroku CLI supports just that with

heroku deploy:jar self-contained.jar --app $HEROKU_APP_NAME

Which can be seen in config.yml

Viewing

The latest version should be visible on https://boiling-falls-60288.herokuapp.com

Cloud Foundry

One of my favorite features of CF is the zero-downtime deployments using Blue/Green strategy.

1. Push new version of app on a 'dark' URL not used by customers
2. Validate application health on dark URL
3. Begin routing customer facing URL to new version
4. Stop sending customer traffic to old version
5. Stop and remove previous version

You can see this executed in config.yml

Viewing

And live app visible on https://circleci-challenge.cfapps.io/

Running locally

This project uses spring boot, so run as you would any other like project to start on port :8080 locally.

mvn spring-boot:run

Summary of Learning and Setup

• Getting initial build to compile and pass tests in circleci was straightforward build 3 I am by no means a UI developer, and recalling the setup required to use selenium/phantomjs for Javascript testing was the biggest challenge. Failures were related to phantomjs binary install.
• Subsequently setup heroku account and local CLI, which was easy enough. Following Heroku tutorial locally used the git push heroku master approach, which seems fine for exploratory development. But for production use cases the idea of rebuilding the binary with -DskipTests seemed unnecessary risk. More about that later.
• Adding heroku as isolated job in circleci workflow broke a few builds but back on track by build 12. CircleCI tutorials combine build and deploy in a single job, with entire source directory checked out. Breaking build/test and Deploy into seperate jobs took some tweaking.
• When it came to deploying I really disliked heroku rebuilding my code after it was tested. So I deviated frm circleci tutorial, and instead of pushing git repo, I used CLI solely to push my jar file. This eliminated need for SSH key (git.heroku.com) and verifyHosts hack in tutorial, while also appeasing my "build once run anywhere" desires.
• By build 17 the end to end workflow with seperate build and deploy jobs was passing. Heroku cli deploys the jar which is passed via circleCI's workspace support.
• Being much more comfortable with Cloud Foundry, was able to add that entire stage successful on first attempt.

Previous CircleCI Experience

Eddie has used CircleCI previously to deploy his personal website built with Hugo. That project's config.yml deploys a test domain for all branches, and a prod domain for master branch only.