Installing numpy on Docker Alpine

Question

I\'m trying to install numpy in a docker container based on Alpine 3.1. I\'m using the following Dockerfile:

FROM alpine:3.1
RUN apk add --update make cmake          


        

Answer 1

A package is now available in the Alpine repository: py3-numpy. But you won't be able to use it straightaway.

py3-numpy installs libraries into /usr/lib/python3.8/site-packages directory but the default Python module path does not use it:

$ docker run -it python:3.8-alpine sh
/ # apk add --update --no-cache py3-numpy
/ # python
>>> import numpy
Traceback (most recent call last):
  File "", line 1, in 
ModuleNotFoundError: No module named 'numpy'
>>> import sys
>>> sys.path
['', '/usr/local/lib/python38.zip', '/usr/local/lib/python3.8', '/usr/local/lib/python3.8/lib-dynload', '/usr/local/lib/python3.8/site-packages']

This can be fixed by setting the $PYTHONPATH environment variable to the path of the site-packages in /usr/lib:

FROM python:3.8-alpine

RUN apk add --update --no-cache py3-numpy
ENV PYTHONPATH=/usr/lib/python3.8/site-packages