Install almost all Python environments on Ubuntu 20.04

install-python.sh

#! /bin/bash
#
# Copyright (c) 2020 Víctor Molina García
# MIT License
#
# Script to install Python environments 2.6+ and 3.2+ using PyEnv
# and the installation steps for OpenSSL 1.0.2 mostly based on the
# information available in the following link:
#     http://www.linuxfromscratch.org/blfs/view/7.7/postlfs/openssl.html
#
# Tested on Ubuntu 20.04; bash is required because otherwise the PyEnv
# initialisation command fails.
#

# Set to exit on error.
set -e
cwd=$(pwd)

# Install basic dependencies.
echo "Installing basic dependencies..."
sudo apt-get install -y build-essential wget curl llvm git libssl-dev tk-dev  \
                        libncursesw5-dev libreadline-dev libsqlite3-dev       \
                        libffi-dev xz-utils zlib1g-dev libbz2-dev liblzma-dev

sudo apt-get install -y openssl ca-certificates

# Download and install OpenSSL 1.0.2.
openssl_name=openssl-1.0.2
openssl_targz=$openssl_name.tar.gz
openssl_patch=$openssl_name-fix_parallel_build-1.patch
openssl_dir=$HOME/.local/opt/$openssl_name
openssl_inc=$openssl_dir/include
openssl_lib=$openssl_dir/lib
openssl_ssl=$openssl_dir/ssl

echo "Downloading OpenSSL..."
wget https://www.openssl.org/source/$openssl_targz
wget https://www.linuxfromscratch.org/patches/downloads/openssl/$openssl_patch

echo "Decompressing OpenSSL..."
tar -xf $openssl_targz

echo "Patching OpenSSL..."
cd $openssl_name
patch -Np1 -i ../$openssl_patch

echo "Installing OpenSSL..."
./config --prefix=$openssl_dir --openssldir=$openssl_dir/ssl --libdir=lib     \
         -Wl,-rpath=$openssl_dir/lib shared zlib-dynamic
make
make install

cd $cwd
rm -rf $openssl_name

echo "Linking CA certificates..."
rmdir $openssl_ssl/certs && ln -s /etc/ssl/certs $openssl_ssl/certs

# Download PyEnv from its GitHub repository.
export PYENV_ROOT=$HOME/.local/share/pyenv
export PATH=$PYENV_ROOT/bin:$PATH
git clone https://github.com/pyenv/pyenv.git $HOME/.local/share/pyenv
eval "$(pyenv init -)"
echo "Installing all Pythons..."

# Install Python versions that can use OpenSSL v1.1.
pyenv install 3.9.0
pyenv install 3.8.6
pyenv install 3.7.9
pyenv install 3.6.12
pyenv install 3.5.10
pyenv install 2.7.18

# Install Python versions that require the elder OpenSSL v1.0.2.
export CFLAGS="-I$openssl_inc"
export LDFLAGS="-L$openssl_lib"
export LD_LIBRARY_PATH="$openssl_lib"
pyenv install 3.4.10
pyenv install 3.3.7
pyenv install 3.2.6
pyenv install 2.6.9

echo "Remember to set LD_LIBRARY_PATH=$openssl_lib in your .bashrc file:"
echo "    LD_LIBRARY_PATH=$openssl_lib:\$LD_LIBRARY_PATH"

I have applied two main changes:

• The Python versions are updated to the latest patch version, and Python 3.9 is added.
• I found that the SSL library was not working with https links and OpenSSL 1.0.2 (python < 3.5, python != 2.7) due to the lack of certificates. I workaround it by installing ca-certificates and adding a symbolic link to them for OpenSSL 1.0.2.

Thanks the old OpenSSL installation!

Thanks a lot bro, i was needing old python to test an arduino esp32 emulator, works like a charm! love and hugs for you.

@molinav I am getting a 403 error when trying to download the patch file from here: http://www.linuxfromscratch.org/patches/blfs/7.7/openssl-1.0.2-fix_parallel_build-1.patch Do you know where I can get that file from?

@fc2brown You can try commenting out lines 43-45. If I remember correctly, the patch was fixing the parallel build of OpenSSL 1.0.2 but nothing from the OpenSSL source code. It will simply compile with one single process.

You can also replace line 28 with openssl_name=openssl-1.0.2j. OpenSSL 1.0.2j is the last version that works with all the EOL Python versions.

@fc2brown You can try commenting out lines 43-45. If I remember correctly, the patch was fixing the parallel build of OpenSSL 1.0.2 but nothing from the OpenSSL source code. It will simply compile with one single process.

You can also replace line 28 with openssl_name=openssl-1.0.2j. OpenSSL 1.0.2j is the last version that works with all the EOL Python versions.

Found this new patch link:
https://www.linuxfromscratch.org/patches/downloads/openssl/openssl-1.0.2-fix_parallel_build-1.patch

@ewertao Thanks! I have just updated the gist.