How to Deploy Docker Container on Heroku? | Part - 2

In the previous article, we’ve seen about How to Deploy a Flask app on Heroku. If you haven’t seen it yet, click the below link to see it.

How to Deploy a Flask app on Heroku? | Part - 1

Structure of Folder -

app/
  app.py
  requirements.txt
  Dockerfile
  docker-compose.yml

1. Create a New Folder, Go inside it. Initialize it as Git Repository.

mkdir your-folder-name
cd your-folder-name
git init

2. Create a Simple Hello World Flask Application

app.py

from flask import Flask
from os import environ
app = Flask(__name__)
@app.route('/')
def hello():
  return "Hello World!"
if __name__ == '__main__':
  app.run(debug = True, host = '0.0.0.0', port=environ.get("PORT", 5000))

3. Add the libraries which you have used in this Application in requirements.txt

requirements.txt

flask

4. Create a Dockerfile to dockerize the Flask Application

Dockerfile

FROM python:3.8-alpine
WORKDIR /app
ADD . /app
RUN pip install -r requirements.txt
CMD ["python", "app.py"]
EXPOSE 5000

5. Create a docker-compose.yml file

docker-compose.yml

version: '2'
services:
    web:
        build: .
        ports: 
            - "5000:5000"
        volumes:
            - .:/app

6. Run locally by using the below command and check whether it is working or not

sudo docker-compose up

Press Ctrl + C to stop the running container.

7. Login into your Heroku and Docker account

heroku login
sudo docker login --username=<username> --password=<password>

8. Login into Heroku Container

sudo heroku container:login

9. Create a new Heroku app and add the Existing local directory to Remote Heroku Repository

heroku create <app-name>
heroku git:remote -a <app-name>

10. Push and Release

sudo heroku container:push web --app <app-name>
sudo heroku container:release web --app <app-name>

Open browser and Enter the URL https://<app-name>.herokuapp.com/

You can see the output Hello World! in the browser.

Thank you for reading this article.