Installs pyenv, virtualenvwrapper, pyenv-virtualenvwrapper, pyenv-default-packages, and installs python3 with pyenv

python.sh

#shellcheck shell=bash source=/dev/null

# This script is sourced in order to setup python3 with pyenv/virtualenvwrapper with the 
# pyenv-virtualenvwrapper plugin. The pyenv-default-packages plugin is also installed 
# to install ansible and dependencies. This is for a service account to be used by admins
# who aren't experienced with python ecosystem it must also not modify or use the 
# system python environment.

# function: _install_os_deps: installs operating system package dependencies
function _install_os_deps(){
  if yum list installed zlib-devel bzip2 bzip2-devel readline-devel sqlite \
  sqlite-devel openssl-devel xz xz-devel libffi-devel findutils >/dev/null 2>&1; then
    return
  else
    if sudo yum install -y zlib-devel bzip2 bzip2-devel readline-devel sqlite \
    sqlite-devel openssl-devel xz xz-devel libffi-devel findutils >/dev/null 2>&1; then # needed for python builds
      return 0
    fi
  fi
}

# function: _install_pyenv: installs python version manager
function _install_pyenv() {
  if [[ -d ~/.pyenv ]]; then
    return
  else
    echo "==> Installing pyenv and dependencies..."
    echo "==> This process should only occur once unless ~/.pyenv is deleted"
    if ! _install_os_deps; then
      echo "==> Could not install python build dependencies!"
      return $?
    fi
    if git clone https://github.com/pyenv/pyenv.git "$HOME/.pyenv" >/dev/null 2>&1; then
      echo "==> Success"
    else
      return $?
    fi
  fi
}

# function: _install_pyenv-default-packages: installs plugin to install default packages automatically
function _install_pyenv-default-packages(){
  if [[ -d "${PYENV_ROOT}/plugins/pyenv-default-packages" ]]; then
    return
  else
    echo "==> Installing pyenv-default-packages plugin..."
    echo "==> This process should only occur once unless ~/.pyenv/plugins/pyenv-default-packages is deleted"
    # Install pyenv virtualenvwrapper plugin
    if git clone https://github.com/jawshooah/pyenv-default-packages.git "$HOME/.pyenv/plugins/pyenv-default-packages" >/dev/null 2>&1; then
      PATH="$PATH:${PYENV_ROOT}/plugins/pyenv-default-packages/libexec"; export PATH
      echo -en "ansible\npywinrm[kerberos]>=0.3.0\n" >  "$(pyenv root)/default-packages"
      echo "==> Success"
    fi
  fi
}

# function: _install_python 
function _install_python() {
  # Install python 3.7.2  if not already installed, python is needed for virtualenvwraper
  if pyenv which python3.7 >/dev/null 2>&1; then
    return
  else
    echo "==> Installing local python 3.7.2 using pyenv"
    CFLAGS='-O2'; export CFLAGS
    if ! pyenv install 3.7.2 >/dev/null 2>&1; then
      return $?
    fi
  fi
}

# function: _install_pyenv_wrapper: installs plugin to combine pyenv and virtualenvwrapper functions
function _install_pyenv_wrapper(){
  if [[ -d "${PYENV_ROOT}/plugins/pyenv-virtualenvwrapper" ]]; then
    return
  else
    echo "==> Installing pyenv-virtualenvwrapper plugin..."
    echo "==> This process should only occur once unless ~/.pyenv/plugins/pyenv-virtualenvwrapper is deleted"
    # Install pyenv virtualenvwrapper plugin
    if git clone https://github.com/pyenv/pyenv-virtualenvwrapper.git "$HOME/.pyenv/plugins/pyenv-virtualenvwrapper" >/dev/null 2>&1; then
      PATH="$PATH:${PYENV_ROOT}/plugins/pyenv-virtualenvwrapper/bin"; export PATH
      echo "==> Success"
    else
      return $?
    fi
  fi
}

#function: virtualenvwrapper: setup virtualenvwrapper
function _pyenv_virtualenvwrapper() {
  if [[ ! -d "${PYENV_ROOT}/plugins/pyenv-virtualenvwrapper" ]]; then
    return
  else
    WORKON_HOME=~/.virtualenvs; export VIRTUALENVWRAPPER_VIRTUALENV_ARGS
    PROJECT_HOME=~/projects; export PROJECT_HOME
    VIRTUALENVWRAPPER_VIRTUALENV_ARGS='--no-site-packages'; export WORKON_HOME
    mkdir -p "${WORKON_HOME}"
    mkdir -p "${PROJECT_HOME}"
    pyenv virtualenvwrapper
  fi
}

# If ~/.local exist delete it
if [[ -d ~/.local ]]; then
  rm -rf ~/.local
fi

# Install pyenv
_install_pyenv ||  return
PYENV_ROOT="$HOME/.pyenv"; export PYENV_ROOT
PATH="${PYENV_ROOT}/bin:$PATH"; export PATH

# Install plugins for pyenv
_install_pyenv-default-packages || return
_install_pyenv_wrapper || return

# Enable shims and autocompletion
eval "$(pyenv init -)" ||  return

# Install python 
_install_python || return
pyenv global 3.7.2 >/dev/null 2>&1 # set default python installation
pyenv shell 3.7.2  # set shell python version

# Initialize pyenv-virtualenvwrapper
_pyenv_virtualenvwrapper || return