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Dockerize Flask App

Prerequisites

To complete this tutorial, you will need the following:

• Docker installed on your computer
• A text editor for writing code
• A basic knowledge of Python

Create a Basic Flask App

Create a file called app.py in your project directory. This will contain the basic code for your flask app.

from flask import Flask

app = Flask(__name__)

@app.route('/')
def hello_world():
    return 'Hello, World!'

if __name__ == '__main__':
    app.run(debug=True, host='0.0.0.0')

Create a Dockerfile

Create a file called Dockerfile in your project directory. This will contain the instructions for creating the Docker image.

FROM python:3.7.7-slim
WORKDIR /app
COPY . /app
RUN pip install -r requirements.txt
EXPOSE 5000
CMD ["python", "app.py"]

Create a Requirements File

Create a file called requirements.txt in your project directory. This will list all of the packages that your application needs in order to run.

$ pip freeze > requirements.txt

Build the Docker Image

Run the following command from the project directory to build your Docker image.

docker build -t my-flask-app .

Run the Docker Image

Run the following command to start the Docker container with your new image.

docker run -d -p 5000:5000 my-flask-app

Your application should now be running on port 5000 of your local machine.