Cache your pip wheels in docker using devpi, with graceful fails

app_entry_points.sh

# your code here
if [ "$1" = '' ]; then
  run_my_app.sh
fi

if [ "$1" = 'devpiupload' ]; then
  # this will build and upload project requirements to devpi cache container
    
  # install build requirements
  cd requirements
  apt-get update
  apt-get install $(cat system.build.reqs.txt|grep -v '^#'|xargs)
  
  # download packages and build wheels in the deploy environment
  # they will be in ./requirements/packages and ./requirements/wheelhouse
  pip install --download=packages -r requirements.txt
  pip wheel --wheel-dir=wheelhouse -r requirements.txt

  # upload to devpi, making a user and index if needed
  pip install "devpi-client>=2.3.0"
  
  # since it's published ports we can access it from the host_ip:port
	export HOST_IP=$(ip route| awk '/^default/ {print $3}')
		if devpi use http://$HOST_IP:3141>/dev/null; then
	     echo devpi detected on http://$HOST_IP:3141
	else 
        echo No started devpi container found at http://$HOST_IP:3141;
	fi
	
  # check that a user and index have been created else create them
  if devpi login app --password=$DEVPI_PASSWORD > /dev/null; then
      echo  devpi user (app) lready created
  else
      devpi user -c app password=$DEVPI_PASSWORD
      devpi index -c app/dev bases=
      devpi login app --password=$DEVPI_PASSWORD
  fi

  # upload to devpi
	devpi use http://$HOST_IP:3141/app/dev --set-cfg 
	devpi upload --from-dir --formats=* ./wheelhouse ./packages; 
	
fi

docker-compose.yml

# Build and serve pip packages and wheels to speed development
devpi:
  image: scrapinghub/docker-devpi
  volumes:
    - /mnt
    - /var/lib/devpi
  ports:
    - 3141:3141
  env:
   - DEVPI_PASSWORD=$(echo $(lscpu)|md5sum) # replace this password, this is just a hash of some system info
  restart: always

Dockerfile

# This code will use the devpi cache if it can be found
# otherwise fail with a few complaints
RUN export HOST_IP=$(ip route| awk '/^default/ {print $3}') \
 && mkdir -p ~/.pip \
 && echo [global] >> ~/.pip/pip.conf \
 && echo extra-index-url = http://$HOST_IP:3141/app/dev/+simple >> ~/.pip/pip.conf \
 && echo [install] >> ~/.pip/pip.conf \
 && echo trusted-host = $HOST_IP >> ~/.pip/pip.conf \
 && cat ~/.pip/pip.conf
 
# if it's working you will see out put including:
#  2 location(s) to search for versions of ignoredd:
#  * https://pypi.python.org/simple/ignoredd/
#  * http://172.17.0.1:3141/app/dev/+simple/ignoredd/
RUN pip install -v ignoredd
 
# you can add code to your entrypoint to build and upload packages from the container env
ENTRYPOINT ["./app_entry_points.sh"]
CMD ["devpiupload"] # this can be overridden i nthe yml file

Thank you, this is just what I needed!