How to avoid reinstalling packages when building Docker image for Python projects?
To avoid reinstalling packages when building a Docker image for a Python project, you can create a requirements.txt file that lists all of the packages that your project depends on, and then use the pip install command with the -r flag to install the packages listed in the requirements file during the image build process. This way, when you build the image, the packages will be installed from the cache and not downloaded again.
# Build the requirements file
pip freeze > requirements.txt
# Build your Dockerfile
FROM python:3.8-slim-buster
COPY . /app
WORKDIR /app
RUN pip install --no-cache-dir -r requirements.txt
CMD ["python", "main.py"]?
You can also use multi-stage build to avoid including unnecessary files in the final image.
# Dockerfile
FROM python:3.8-slim-buster as builder
COPY . /app
WORKDIR /app
RUN pip install --no-cache-dir -r requirements.txt
FROM python:3.8-slim-buster
COPY --from=builder /app /app
WORKDIR /app
CMD ["python", "main.py"]
Multi-stage docker build a is a very much beneficial if you are optimising the size of the docker image. Thus, you can leverage the caching of the docker layers.
Comment your thoughts/experiences/issue/concerns. Thank you.