Installing pypy3 and numpy from scratch on Debian 10

Dockerfile

# This Dockefile demonstrates how to install upstream pypy3 on a bare Debian 10
# box from scratch.
#
# To test:
# docker run --rm rjw57/pypy3 \
#       pypy3 -c 'import numpy as np; M=np.array(range(16)).reshape((4,-1)); Q, R = np.linalg.qr(M); [print(x) for x in (M, Q, R, np.dot(Q,R))]'
FROM debian:10

# Install any system-wide dependencies we need including essential packages
# required to compile C-based Python modules.
RUN \
	apt-get -y update \
	&& apt-get -y install build-essential curl

# Specify the pypy version to install here. The version is used to construct the
# download URL for the binary distribution along with the prefix used by the
# binary tarball. It's worth checking which versions of PyPy3 are supported by
# the builds available at https://antocuni.github.io/pypy-wheels/manylinux2010/.
ARG PYPY_VERSION=3.6-v7.3.1
ARG PYPY_ROOT=pypy$PYPY_VERSION-linux64
ARG PYPY_URL=https://bitbucket.org/pypy/pypy/downloads/$PYPY_ROOT.tar.bz2

# Install pypy itself under /opt and symlink the pypy3 binary into
# /usr/local/bin so that it appears on the PATH.
RUN \
	cd /opt \
	&& curl -L "${PYPY_URL}" | tar xjf - \
	&& ln -s "/opt/${PYPY_ROOT}/bin/pypy3" /usr/local/bin/pypy3

# Ensure and update pip.
RUN \
	pypy3 -m ensurepip \
	&& pypy3 -m pip install --upgrade pip

# Install complex packages from a pre-built archive as they are tedious to build.
RUN pypy3 -m pip install \
	--extra-index-url https://antocuni.github.io/pypy-wheels/manylinux2010 \
	numpy==1.18.3

# The cryptography module requires the libssl headers be installed.
RUN apt-get -y install libssl-dev && pypy3 -m pip install cryptography

# Install the remaining pip dependencies.
RUN pypy3 -m pip install \
	pykka ccxt file_read_backwards websocket protobuf pyerf jsonmerge

# Install scipy which takes *forever* and requires some additional system
# dependencies.
RUN \
	apt-get -y install gfortran libopenblas-dev liblapack-dev \
	&& pypy3 -m pip install scipy