Docker/Flask

Dockerfile

# Configures a Flask web server and copies the current folder content
# to use as app root.

# Use the following commands to build and run the server.
#   docker build -t flask-server .
#   docker run -d -p 5000:5000 --name=flask-server flask-server

# Then open a web browser and connect to http://localhost:5000 .

# References:
#   https://code.visualstudio.com/docs/containers/quickstart-python
#   https://aka.ms/vscode-docker-python
#   https://runnable.com/docker/python/dockerize-your-flask-application
#   https://docs.docker.com/develop/develop-images/dockerfile_best-practices/

FROM python:alpine
RUN python -m pip install flask

WORKDIR /usr/src/app
COPY . .

EXPOSE 5000

CMD ["python", "app.py"]

app.py

# Displays "Hello world!"
#
# References:
#   https://en.wikiversity.org/wiki/Flask/Hello_World

import flask

app = flask.Flask(__name__)

@app.route('/')
def root():
    return "Hello world!"

if __name__ == "__main__":
    app.run(host='0.0.0.0', port=5000)

Try It

Online Free

1. Use Play with Docker. Create an account and/or log in.
2. Start an interactive session and add a new instance.
3. In the terminal window, enter the following commands:
   • touch Dockerfile
   • touch app.py
4. Use the Editor button to edit both files and save the contents above into each respective file.
5. Run the following commands:
   • docker build -t flask-server .
   • docker run -d -p 5000:5000 --name=flask-server flask-server
6. In the top window, select the 5000 button to connect to the running server.

On Your Own System

1. Install Docker Desktop or the Docker Engine.
2. Save the files above into a new Docker Flask folder:
   • Dockerfile
   • app.py
3. At a command prompt, change to the Docker Flask folder and then run the following commands:
   • docker build -t flask-server .
   • docker run -d -p 5000:5000 --name=flask-server flask-server
4. Open a web browser to connect to the running server:
   • http://localhost:5000.

See Also

• Server-Side Scripting
• Flask
• Docker: The best way to learn Docker for Free: Play-With-Docker (PWD)

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