Python and multi-stage builds

shanz1999 · February 9, 2021, 5:01pm

I have got a dockerfile based on the full-fat windows,
ie my first line is -
FROM mcr.microsoft.com/windows:1809-amd64

I then install lots of stuff including an app that requires full windows rather than servercore, nanoserver or iotcore.
Now I want to add python 2.7 to my container.
I struggled doing it manually then I tried adding a second FROM command.

FROM winamd64/python:2

But now I fear that my final image is based on Windows Server 2016 rather than Windows.
Also do I need to use the COPY command to copy stuff from one layer to the other?

I think I could just look at the python dockerfile

github.com

docker-library/python/blob/master/3.10-rc/windows/windowsservercore-1809/Dockerfile

#
# NOTE: THIS DOCKERFILE IS GENERATED VIA "update.sh"
#
# PLEASE DO NOT EDIT IT DIRECTLY.
#

FROM mcr.microsoft.com/windows/servercore:1809

SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]

# https://github.com/docker-library/python/pull/557
ENV PYTHONIOENCODING UTF-8

ENV PYTHON_VERSION 3.10.0a5
ENV PYTHON_RELEASE 3.10.0

RUN $url = ('https://www.python.org/ftp/python/{0}/python-{1}-amd64.exe' -f $env:PYTHON_RELEASE, $env:PYTHON_VERSION); \
	Write-Host ('Downloading {0} ...' -f $url); \
	[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; \
	Invoke-WebRequest -Uri $url -OutFile 'python.exe'; \

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and copy it into my dockerfile apart from its first line
(FROM mcr.microsoft.com/windows/servercore:1809).

Is there a recommended approach?

cclauss · February 12, 2021, 11:09am

The strong recommendation is NOT to use Python 2. It has been dead for more than a year and should now be considered an insecure platform. Python 3.10 is an alpha version so it should not be relied on for production workloads. Python 3.9.1 is the current release with Py 3.9.2 scheduled to release in the next few days.

Python can be downloaded from 1. the Microsoft app store, 2. Python.org (like above), or 3. we use pyenv to install multiple versions of Python simultaneously in Docker with great success.