This project meant to explain in an easy way how to:

• Make a dockerized CI/CD pipeline with circle CI
• Deploy the application to Heroku using Github as VCS

• Solves the "work on my machine" issue, guaranteeing that every environment is the same, ie, dev and prod environment will use the same flavor of java in the same OS.
• Allows deploying in any platform from bare metal to the cloud with minimum configuration.

• A Github account
• Open a Circle CI account associated to the Github account created in the first step
• Open a Heroku account, also install the Heroku CLI for your computer.
• The code to deploy, for this example we are using a simple spring boot application generated by start.spring.io

1. In the root of your project create a folder named .circleci
2. In the .circleci folder add the configuration file config.yml for your pipeline you can check the example made for this project here
3. Just push the code and review the pipeline in your CircleCI dashboard 😃

• CircleCI Workflow has a different environment to each step if you want that the info of one step available for other, you need to use the workspace feature
• To be able to deploy to Heroku you need to define the project environment variables HEROKU_APP_NAME and HEROKU_API_KEY. you can achieve this with environment variable feature, Is a safe way to store sensitive information to be used during the pipeline execution
• To obtain the HEROKU_API_KEY value you need to execute locally heroku auth:token
• Heroku uses the port 80 to expose the app, if the app is deployed using docker you must add a line in the application.properties file, the spring configuration will set as default the port 8080 if the $PORT environment variable isn't defined
• We use 2 docker images
  • Dockerfile: run the Compile and Test steps.
  • Dockerfile.runtime: A multistage Dockerfile that is responsible for the Package and Deploy steps.

For further reference, please consider the following sections:

• Docker deploys
• Releases and Rollback
• (Video) Run Spring boot app in heroku
• (Video) Build and Deploy Heroku Apps using docker

• Configuration reference
• Workflow Documentation
• Using CircleCI workflows to replicate Docker Hub automated builds
• (Video)Workflow demo