docker.md

Docker Python documentation:
https://hub.docker.com/_/python

1. Install docker into the main folder of your app via the terminal (no need to start venv):

    $ brew install --cask docker
   

2. Create a profile on Docker Hub, then log into Docker Hub via the terminal (input your password when prompted):

    $ docker login
   

3. Create the requirements file:

    $ pip freeze > requirements.txt
   

*To run the app independently of Docker, install requirements and run flask in venv:

    (venv) $ pip install -r requirements.txt
    (venv) $ flask run

4. Create Dockerfile:

    $ touch Dockerfile
   

5. Populate Dockerfile with the following:

The starter image can be a variant, here alpine (otherwise FROM python:3 is enough)

    FROM python:3.9-alpine

    WORKDIR /usr/src/app

    # Install dependencies
    COPY requirements.txt ./
    RUN pip install --no-cache-dir -r requirements.txt

    # Install the app (copies everything form present dir on computer, to the container)
    COPY . .            

    # Needed with Flask to acces this port
    EXPOSE 5000

    # Start the app (has to be an array)
    CMD [ "flask", "run" ]

*The default is a linux file system, here we create a file app (COPY needs to be updated as well if this option is chosen):

    RUN mkdir /app
    COPY . /app 

6. Create a Docker image via the terminal (the dot at the end means "in this folder") giving it a name for the Docker repository:

    $ docker build -t my-python-app .
   

7. Run the app on your computer with, giving it a running name:

    $ docker run -it --rm --name my-running-app my-python-app