Deploy Docker image to Heroku with CicleCI

Heroku is a functional PaaS that can deploy the Docker image, and CircleCI is also useful SaaS for CI/CD.

In this post, I show an example of CircleCI config which deploys the Docker image to Heroku.

Actually, I had trouble when setting it up. 🤣

Prerequisite

Code repository and CircleCI had already connected

Created Heroku app for deploying the Docker image

Generated Heroku API Key in Manage Account view on Heroku

Set up

Environment Variable

Set environment variables on your project settings in CircleCI.

Name	Value
HEROKU_API_KEY	Your Heroku API Key
HEROKU_APP_NAME	Heroku app name for deploying the Docker image

config.yml

Modify config.yml below.

jobs:
  # Build the docker image and run tests.
  build_and_test:
    docker:
      - image: cimg/base:2021.07
    steps:
      # For using docker commands.
      - setup_remote_docker:
          version: 19.03.13

      # Build the docker image
      - checkout
      - run: docker build -t webapp .

      # Run tests.
      - run:
          command: docker run webapp python3 tests.py

  # Build the docker image and deploy it to Heroku.
  build_and_deploy:
    docker:
      - image: cimg/base:2021.07
    steps:
      # For using docker commands.
      - setup_remote_docker:
          version: 19.03.13

      # Build the docker image
      - checkout
      - run: docker build .

      # Deploy to Heroku
      - heroku/install
      - run: heroku container:login
      - heroku/push-docker-image:
          process-types: web
      - heroku/release-docker-image:
          process-types: web

orbs:
  # For using Heroku CLI commandｓ.
  heroku: circleci/heroku@1.2.6

version: 2.1
workflows:
  heroku_deploy:
    jobs:
      - build_and_test
      - build_and_deploy:
          requires:
            # Deploy after testing.
            - build_and_test