This is how I package my flask app for docker container

Here is my steps to copy my app to testing server and package it ready for production.

tar -zcf ~/docker/my-flask-app_$(date +"%Y-%m-%d_%H-%M-%S").tar.gz -C ~/codes/python my-flask-app

rsync -a ~/docker/my-flask-app*.tar.gz username@testing-server:~/docker

2. Un tar the package and prepare for Dockerization

tar -xvzf ~/docker/my-flask-app_2024-02-13_15-50-00.tar.gz

cd my-flask-app
# If you are using VENV (which you should use)
source ./venv/bin/activate
# Create the requirement.txt file
pip freeze > requirements.txt

3. Create Dockerfile for creating docker image

# Use an official Python runtime as a parent image
FROM python:3.9-slim

# Set the working directory in the container
WORKDIR /app

# Copy the current directory contents into the container at /app
COPY . /app

# Install any needed dependencies specified in requirements.txt
RUN pip install --no-cache-dir -r requirements.txt

# Make port 5000 available to the world outside this container
EXPOSE 5000

# Define environment variable
ENV FLASK_APP=app.py

# Run app.py when the container launches
CMD ["flask", "run", "--host=0.0.0.0"]

4. Next step is to build the image

docker build -t my-flask-app .

# build from m1 mac for amd64 machine
docker build --platform linux/amd64 -t my-flask-app .

5. Docker run to test the image

docker run -d -p 5001:5000 --name my-flask-app --rm my-flask-app

# docker run
# -d detach mode
# -p port 5001 as outside port : 5000 as the flask app port
# --name name the container
# --rm remove the container after the container stop
# my-flask-app use my-flask-app image

6. Export the docker image for production

docker save -o /path/to/save/your_image.tar your_image_name_or_id

7. After upload the image to production server use -i to import the docker image

docker load -i /path/to/save/your_image.tar
# rename import image
docker tag <image_id> <new_image_name>:<new_tag>

My Flask app

python3 -m venv venv
source ./venv/bin/activate
pip install --upgrade pip
pip install Flask

# After create the flask app
flask run --host=0.0.0.0 --port=8000