Reduce size of Docker image

from flask import Flask, render_template

app = Flask(__name__)

@app.route('/')
def hello():
    return None

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

FROM python:3.9 

WORKDIR /app

COPY . .

RUN pip install flask 

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

Here you can see the size of docker images is around 1 GB.

Here are several tips to help you reduce the size of your Docker images:

1. Use a Minimal Base Image

   Start with a minimal base image, such as ->slim, slim-bullseye, instead of a full-fledged operating system. These lightweight images contain only essential components.

2. Multi-Stage Builds:

   Use multi-stage builds to reduce the size of the final image. This involves using multiple FROM statements in your Dockerfile to create temporary images for building and then copying only necessary artifacts to the final image.

#stage-1
FROM python:3.9 AS stage-1

WORKDIR /app

COPY . .

#stage-2
FROM python:3.9-slim-bullseye      # slim-bullseye is smaller base image 

COPY --from=stage-1 /app /app 

RUN pip install flask 

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

Now after use slim-bullseye base image, you can see that size reduce from 1GB to 135 MB