Sample Java webapp with CI/CD to AWS

Summary

This is a (relatively simple) Java EE web application, built with the Spring platform, which allows a pair of temperature or volume values and units to be specified and this app will indicate whether the two values are equal to each other once each is rounded to the nearest tenth.

Please note that I'm not especially experienced with front-end development, and I just whipped together some jsp code for this app. Most of my experience is with DevOps practices and cloud & container technologies, and Java back-end application development. This app shows just a sample of some of my skills/experiences. Given that since 2017 I've been focusing on DevOps/Cloud, I think this app shows an amply sufficient sampling of my Java coding skills, and if I were to dedicate more time to this app it would be to further showcase my DevOps skills (as described further in the "Prioritized To-do List" section below), given that manually setting up an environment/app in AWS Elastic Beanstalk isn't a very good representation of my DevOps skills. But at least this sample app shows a functioning automated CI/CD pipeline for builds & deployments.

Deployed in AWS

There's an instance of this application running at: http://jolson490-sampleapp.us-east-2.elasticbeanstalk.com/ (please feel free to play around with it and check it out!)

CI/CD

Via AWS CodePipeline, the following is setup:

• A GitHub webhook triggers the pipeline whenever a commit is pushed to the master branch of this repo - at which point a build in AWS CodeBuild is started. Automated tests are run as part of the build, and if any of the tests fail then the build will fail too.
• If/when a build finishes successfully, then the pipeline deploys the build artifact to an environment in AWS Elastic Beanstalk (which is available at the aforementioned URL).

Tech Stack

Application: Java, Spring Boot and Spring MVC with JSP, Tomcat, Log4j2, and Maven.

CI/CD: AWS (CodePipeline, CodeBuild, & Elastic Beanstalk).

Demo

Something that I would be happy to demo for you:

• We'd go to the home page of this app in AWS and take note of the date/time that is displayed.
• I'd push a commit to the master branch of this repo. (Any commit that doesn't break the app will do - e.g. changing the static text on the home page of the app.)
• Within ~2 minutes, on the home page we'd see an updated date/time - which shows that the pipeline did its thing.

Prioritized To-do List

This section contains the list (in priority order - highest priority items listed first) of development tasks I would do next to improve this app (if I were getting paid to work on this app ).

Assuming this is an app that is used by clients and that this app has an SLA such that our organization making $ is dependent on the app staying up ~99% of the time, here's the MVP to be done prior to this app being made publicly available in a production environment:

• Add more automated tests to cover the rest of the app besides the determineOutput method in UnitsController.
• Create an error page - so that trying to access a page that doesn't exist (e.g. http://jolson490-sampleapp.us-east-2.elasticbeanstalk.com/xyz) doesn't yield the generic "Whitelabel Error Page".
• Create both a non-production (e.g. dev) and production instance of this app. Change the production URL from http://jolson490-sampleapp.us-east-2.elasticbeanstalk.com/sampleapp/ to https://sampleapp.encom.us (e.g. perhaps via AWS Route 53). Setup dev as https://dev.sampleapp.encom.us. Continue to have the current pipeline for dev. Determine whether there should be a manual approval needed before a pipeline deploys a new commit/release to production. And for production have the last updated/deployed date/time be a hidden html field - not displayed on the rendered html.
• Setup monitoring to notify the developer team supporting this app at least 1 month in advance of when the SSL certificate is going to expire.
• Setup New Relic to monitor the app - such that if the app is down then send a notification to the team: via Slack for any/all environments, and via PagerDuty for production.
• It might be ideal to change the primary appender in log4j2-prod.xml to write the logs to an external location, such as Splunk, if it ends up being inconvenient/insufficient to access the logs via AWS Elastic Beanstalk.
• Depending on the anticipated usage of the app, consider whether we need to do any of the following: make the app more secure (e.g. add authentication), specify any JVM arguments (e.g. for heap size), and/or setup the Auto Scaling group in the Elastic Beanstalk environment to do load balancing (to handle increased usage of the app).

And here's the list of non-development tasks (i.e. probably no code changes involved) I'd do prior to this app going live in production:

• I'd upgrade to GitHub Pro so that it could be enabled for PRs to be required for commits to the master branch of this repo. And I'd setup a PR merge check to require that the automated tests must pass in order for any PR to be merged to the master branch.
• Have this app reviewed by the security and legal folks - e.g. ask legal if an Oracle commercial license needs to be purchased in order to legally use Oracle JDK in production (perhaps unless we're using OpenJDK).

And some post-MVP development tasks:

• Codify the pipeline, which was created manually via the AWS console (per these instructions).
• Consider if we need other types of tests besides org.junit.Test - e.g. perhaps some Selenium tests. Verify the app works on each browser (and given versions of those browsers) that the app is required to support.
• Generate javadocs.
• Have a front-end developer give this app a major face lift.
• Utilize AJAX so the user can click the Check Answer button multiple times without the page being re-loaded each time.
• Ask the other developers maintaining this app if we'd all like to have the same formatting applied automatically by our IDE whenever we save a file, so all the code in this repo is formatted the same way - for consistency/readability. e.g. if we're all using Eclipse then check in the .settings/ directory to GitHub.
• Consider containerizing the app (probably with Docker) and migrating it from Elastic Beanstalk to either Kubernetes (perhaps Amazon EKS) or to AWS Fargate (with the Fargate launch type - assuming we don't care to maintain EC2 instances but rather that we prefer to go serverless).

Developer Localhost Instructions

This section contains info for any developer interested in setting up & experimenting with this application on your own machine.

Eclipse of course isn't the only way to run this application, but these instructions assume you're using Eclipse (personally I use "Eclipse IDE for Enterprise Java Developers").

In addition to Eclipse, you need the following installed on your machine:

• JDK version 8
• The Lombok Project
• Spring Tools 4

Setup in Eclipse:

• Do git clone https://github.com/jolson490/sample-webapp-cicd.git in your Eclipse workspace folder.
• Import, Maven, Existing Maven Projects, then choose the sample-webapp-cicd folder you just obtained via git clone.
• Right-click this sample-webapp-cicd project in Eclipse, Run As, Maven install.
• If needed to resolve any errors in Eclipse: right-click the project, Maven, Update Project.

To start the application in Eclipse: click the project, Alt+Shift+X,B to Run Spring Boot App. Then you can access the application via your browser at: http://localhost:8080/sampleapp/