How to reduce the build time/cache Docker image layer in subsequent GitHub Actions runs?

Question

I have a Dockerfile with ubuntu:22.04 as a base image and a manual Python installation(specific version i.e., 3.11.1) layer which takes a long time. How to cache this manual Python installation layer in the docker image in subsequent CI runs in GitHub actions?

Dockerfile:

FROM --platform=linux/amd64 ubuntu:22.04 as base
USER root
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
ENV DEBIAN_FRONTEND noninteractive
COPY ZscalerRootCertificate-2048-SHA256.crt /usr/local/share/ca-certificates/ZscalerRootCertificate-2048-SHA256.crt
RUN apt-get update && \
 apt-get upgrade -y && \
 apt-get install -y software-properties-common ca-certificates && \
 update-ca-certificates
RUN mkdir /python && cd /python && \
 wget https://www.python.org/ftp/python/3.11.1/Python-3.11.1.tgz && \
 tar -zxvf Python-3.11.1.tgz && \
 cd Python-3.11.1 && \
 ls -lhR && \
 ./configure --enable-optimizations && \
 make install && \
 rm -rf /python
# Fail soon than later, if python wasn't installed
RUN python --version
COPY . /app
WORKDIR /app
RUN python -m pip install -U pip
RUN python3.11 -m pip install --no-cache-dir --trusted-host pypi.org --trusted-host files.pythonhosted.org -r requirements/core-requirements.txt
CMD ["gunicorn", "main:app", "--workers", "2", "--worker-class", "uvicorn.workers.UvicornWorker", "--bind", "0.0.0.0:80"]

GitHub workflow,

CI.yml:

name: Docker Image CI
env:
 CONTAINER_NAME: my-use-case
on:
 workflow_dispatch:
concurrency:
 group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
 cancel-in-progress: true
permissions:
 id-token: write
 contents: write
jobs:
 integration-tests:
 name: Integration Test
 runs-on: ubuntu-latest
 
 steps:
 - name: Checkout code
 uses: actions/checkout@v3
 - name: View directory files
 run: |
 pwd
 echo "$PATH"
 - name: Set up Python
 uses: actions/setup-python@v4
 with:
 python-version: "3.11.1"
 - name: Copy Python binaries to Docker context
 run: |
 mkdir -p Python/3.11.1
 cp -r $RUNNER_TOOL_CACHE/Python/3.11.1/* Python/3.11.1
 - name: View directory files
 run: |
 ls -lhR
 echo "$PATH"
 - name: Install dependencies
 run: |
 python --version
 python -m pip install --upgrade pip
 - name: View directory files
 run: |
 ls -lhR
 - name: Build & push docker image
 uses: docker/build-push-action@v2
 with:
 context: .
 push: false
 tags: ${{ env.CONTAINER_NAME }}:${{ github.run_number }}
 file: ./Dockerfile 

• shaik moeed: This question is new but has something relevant to my old question
• Peilonrayz: Why do you need the final two RUN commands after COPY . /app? ("RUN python -m pip install -U pip" and "RUN python3.11 -m pip install ...")
• shaik moeed: @Peilonrayz Yeah, now I realize that I can copy the requriements.txt file first, then the RUN command, and then the final COPY . /app command. Thanks for your details suggestion on my previous question.
• Ajinkya Kamat: If your code depends on the minor version of something you got a bigger problems than speeding up builds on CI.
• Peilonrayz: @AjinkyaKamat Whilst you're probably right you shouldn't depend on minor versions. Python makes no guarantee the code will work across minor versions. You can just look at the typing module in 3.5 which radically changed the internals numerous times across minor versions. Additionally I've seen minor versions introduce bugs. Version pinning to a specific version (minor included) isn't really bad when Python makes no guarantee about minor version compatibility.