build-cpython.sh

#!/bin/bash
# Top-level build script called from Dockerfile

# Stop at any error, show all commands
set -exuo pipefail

# Get script directory
MY_DIR=$(dirname "${BASH_SOURCE[0]}")

# Get build utilities
source $MY_DIR/build_utils.sh


CPYTHON_VERSION=$1
CPYTHON_DOWNLOAD_URL=https://www.python.org/ftp/python


function pyver_dist_dir {
	# Echoes the dist directory name of given pyver, removing alpha/beta prerelease
	# Thus:
	# 3.2.1   -> 3.2.1
	# 3.7.0b4 -> 3.7.0
	echo $1 | awk -F "." '{printf "%d.%d.%d", $1, $2, $3}'
}


CPYTHON_DIST_DIR=$(pyver_dist_dir ${CPYTHON_VERSION})
fetch_source Python-${CPYTHON_VERSION}.tgz ${CPYTHON_DOWNLOAD_URL}/${CPYTHON_DIST_DIR}
fetch_source Python-${CPYTHON_VERSION}.tgz.asc ${CPYTHON_DOWNLOAD_URL}/${CPYTHON_DIST_DIR}
gpg --import ${MY_DIR}/cpython-pubkeys.txt
gpg --verify Python-${CPYTHON_VERSION}.tgz.asc
tar -xzf Python-${CPYTHON_VERSION}.tgz

function build {
	IS_SHARED=$1
	pushd Python-${CPYTHON_VERSION}
	PREFIX="/opt/_internal/cpython-${CPYTHON_VERSION}"
	if [ ${IS_SHARED} -eq 1 ]; then
		PREFIX="${PREFIX}-shared"
	fi
	mkdir -p ${PREFIX}/lib
	if [ "${AUDITWHEEL_POLICY}" == "manylinux2010" ]; then
		# The _ctypes stdlib module build started to fail with 3.10.0rc1
		# No clue what changed exactly yet
		# This workaround fixes the build
		LIBFFI_INCLUDEDIR=$(pkg-config --cflags-only-I libffi  | tr -d '[:space:]')
		LIBFFI_INCLUDEDIR=${LIBFFI_INCLUDEDIR:2}
		cp ${LIBFFI_INCLUDEDIR}/ffi.h ${LIBFFI_INCLUDEDIR}/ffitarget.h /usr/include/
	fi
	# configure with hardening options only for the interpreter & stdlib C extensions
	# do not change the default for user built extension (yet?)
	if [ ${IS_SHARED} -eq 1 ]; then
		FLAVOR="--enable-shared"
		FLAVOR_LDFLAGS="-Wl,-rpath=${PREFIX}/lib"
	else
		FLAVOR="--disable-shared"
		FLAVOR_LDFLAGS=
	fi

	./configure \
		CFLAGS_NODIST="${MANYLINUX_CFLAGS} ${MANYLINUX_CPPFLAGS}" \
		LDFLAGS_NODIST="${MANYLINUX_LDFLAGS} ${FLAVOR_LDFLAGS}" \
		--prefix=${PREFIX} ${FLAVOR} --with-ensurepip=no > /dev/null
	make > /dev/null
	make install > /dev/null
	if [ "${AUDITWHEEL_POLICY}" == "manylinux2010" ]; then
		rm -f /usr/include/ffi.h /usr/include/ffitarget.h
	fi
	popd

	if [ ${IS_SHARED} -eq 0 ]; then
		# we don't need libpython*.a, and they're many megabytes
		find ${PREFIX} -name '*.a' -print0 | xargs -0 rm -f
	fi

	# We do not need precompiled .pyc and .pyo files.
	clean_pyc ${PREFIX}

	# Strip ELF files found in ${PREFIX}
	strip_ ${PREFIX}
}

build 0
if [ ${PY_SHARED-0} -eq 1 ]; then
	build 1
fi

rm -rf Python-${CPYTHON_VERSION} Python-${CPYTHON_VERSION}.tgz Python-${CPYTHON_VERSION}.tgz.asc