Configure Python develop tool chain

- use pyenv to manage the develop environments
  + install several Python versions (3.7 - 3.10 and 2.7)
  + each version receives its own copies of black, pipenv, and poetry
- add two more virtual environments based off the latest version:
  + "interactive" => default environment optimized for interactive
                     usage with with black, bpython, and ipython
                     (also receives accidental `pip install`s)
  + "utils" => hosts various globally available tools/apps
               (e.g., mackup and youtube-dl)
- add installation and update scripts for the entire tool chain
- set up completions for bash and zsh
- set up convenient aliases
- configure bpython
- configure poetry

.bashrc

@@ -5,6 +5,12 @@
 [[ $- != *i* ]] && return
 
 
+# Check if a command can be found on the $PATH
+_command_exists() {
+    command -v "$1" 1>/dev/null 2>&1
+}
+
+
 
 # Enable XON/XOFF software flow control
 stty -ixon
@@ -69,6 +75,13 @@ if ! shopt -oq posix; then
     fi
 fi
 
+# Enable completions for various tools
+_command_exists invoke && eval "$(invoke --print-completion-script=bash)"
+_command_exists nox && eval "$(register-python-argcomplete nox)"
+_command_exists pip && eval "$(pip completion --bash)"
+_command_exists pipx && eval "$(register-python-argcomplete pipx)"
+_command_exists poetry && eval "$(poetry completions bash)"
+
 # Add tab completion for all aliases to commands with completion functions
 # (must come after bash completions have been set up)
 # Source: https://superuser.com/a/437508
@@ -193,5 +206,21 @@ _prompt_jobs() {  # Indicate running background jobs with a"%"
       (( $(jobs -rp | wc -l) )) && printf "\033[0;32m %\033[0m"
 }
 
-PS1='${chroot:+($_debian_chroot)}\w$(_prompt_git)$(_prompt_jobs) > '
+_prompt_pyenv() {  # Mimic zsh's pyenv/venv integration
+    if [ -n "$VIRTUAL_ENV" ]; then
+        echo -e "\033[0;36m py $(python -c "import os, sys; (hasattr(sys, 'real_prefix') or (hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix)) and print(os.path.basename(sys.prefix))")\033[0m"
+    elif [ -n "$PYENV_VERSION" ]; then
+        if [ "$PYENV_VERSION" != "system" ]; then
+            echo -e "\033[0;36m py $PYENV_VERSION\033[0m"
+        fi
+    elif [ -f "$(pwd)/.python-version" ]; then
+        echo -e "\033[0;36m py $(cat .python-version | sed ':a;N;$!ba;s/\n/:/g')\033[0m"
+    fi
+}
+
+# Disable the default prompts set by pyenv and venv
+export PYENV_VIRTUALENV_DISABLE_PROMPT=1
+export VIRTUAL_ENV_DISABLE_PROMPT=1
+
+PS1='${chroot:+($_debian_chroot)}\w$(_prompt_git)$(_prompt_jobs)$(_prompt_pyenv) > '
 PS2='... '

.config/bpython/config

@@ -0,0 +1,7 @@
+[general]
+
+# Make `bpython` and `python` share their history
+hist_file = ~/.python_history
+
+# No limit
+hist_length = 0

.config/git/ignore

@@ -1,3 +1,6 @@
+# pyenv
+.python-version
+
 # Vim
 # Source: https://github.com/github/gitignore/blob/main/Global/Vim.gitignore
 #

.config/pypoetry/config.toml

@@ -0,0 +1,3 @@
+[virtualenvs]
+create = true
+in-project = true

.config/shell/aliases.sh

@@ -86,6 +86,25 @@ alias more='less'
 alias tree='tree -C --dirsfirst'
 
 
+# Make working with Python more convenient
+
+# Interactive shells
+alias py='python'
+alias bpy='bpython'
+alias ipy='ipython'
+
+if _command_exists poetry; then
+    alias pr='poetry run'
+fi
+
+if _command_exists pyenv; then
+    alias pyvenvs='pyenv virtualenvs --bare --skip-aliases'
+    alias pyver='pyenv version'
+    alias pyvers='pyenv versions --skip-aliases'
+    alias pywhich='pyenv which'
+fi
+
+
 # Various one-line utilities
 alias datetime='date +"%Y-%m-%d %H:%M:%S %z (%Z)"'
 alias datetime-iso='date --iso-8601=seconds'

.config/shell/utils.sh

@@ -9,6 +9,15 @@ _in_zsh() {
     [ -n "$ZSH_VERSION" ]
 }
 
+prepend-to-path () {  # if not already there
+    if [ -d "$1" ] ; then
+        case :$PATH: in
+            *:$1:*) ;;
+            *) PATH=$1:$PATH ;;
+        esac
+    fi
+}
+
 
 
 # Configure the keyboard:
@@ -19,6 +28,16 @@ _command_exists xcape && xcape -e "Caps_Lock=Escape"
 
 
 
+_init_pyenv () {  # used further below as well
+    _command_exists pyenv || return
+
+    eval "$(pyenv init -)"
+    eval "$(pyenv virtualenv-init -)"
+}
+_init_pyenv
+
+
+
 # ==============================
 # Working with files and folders
 # ==============================
@@ -174,6 +193,94 @@ genemail() {
 
 
 
+# ===================================================
+# Set up & maintain the Python (develop) environments
+# ===================================================
+
+
+# TODO: This needs to be updated regularly (or find an automated solution)
+# The Python versions pyenv creates (in descending order
+# Important: The first version also holds the "interactive" and "utils" environments)
+_py3_versions=('3.10.6' '3.9.13' '3.8.13' '3.7.13')
+_py2_version='2.7.18'
+
+# Each Python version receives its own copy of black, pipenv, and poetry
+# (e.g., to avoid possible integration problems between pyenv and poetry
+#  Source: https://github.com/python-poetry/poetry/issues/5252#issuecomment-1055697424)
+_py3_site_packages=('black' 'pipenv' 'poetry')
+
+# The pyenv virtualenv "utils" contains some globally available tools (e.g., mackup)
+_py3_utils=('mackup' 'youtube-dl')
+
+# Important: this REMOVES the old ~/.pyenv installation
+_install_pyenv() {
+    echo "(Re-)Installing pyenv"
+
+    # Ensure that pyenv is on the $PATH
+    # (otherwise, the pyenv installer emits warnings)
+    mkdir -p "$PYENV_ROOT/bin"
+    prepend-to-path "$PYENV_ROOT/bin"
+
+    # Remove old pyenv for clean install
+    rm -rf "$PYENV_ROOT" >/dev/null
+
+    # Run the official pyenv installer
+    curl https://pyenv.run | bash
+
+    # Make pyenv usable after this installation in the same shell session
+    _init_pyenv
+}
+
+create-or-update-python-envs() {
+    _command_exists pyenv || _install_pyenv
+
+    eval "$(pyenv init --path)"
+
+    # Keep a legacy Python 2.7, just in case
+    echo "Installing/updating Python $_py2_version"
+    pyenv install --skip-existing $_py2_version
+    pyenv rehash  # needed on a first install
+    PYENV_VERSION=$_py2_version pip install --upgrade pip setuptools
+    PYENV_VERSION=$_py2_version python -c "import sys; print sys.version"
+
+    for version in ${_py3_versions[@]}; do
+        echo "Installing/updating Python $version"
+        pyenv install --skip-existing $version
+        pyenv rehash  # needed on a first install
+
+        # Start the new environment with the latest pip and setuptools versions
+        PYENV_VERSION=$version pip install --upgrade pip setuptools
+        PYENV_VERSION=$version python -c "import sys; print(sys.version)"
+
+        # Put the specified utilities in the fresh environments or update them
+        for lib in ${_py3_site_packages[@]}; do
+            PYENV_VERSION=$version pip install --upgrade $lib
+        done
+    done
+
+    # Create a virtualenv based off the latest Python version to host global utilities
+    echo "Installing/updating the global Python utilities"
+    pyenv virtualenv $_py3_versions[1] 'utils'
+    pyenv rehash  # needed on a first install
+    PYENV_VERSION='utils' pip install --upgrade pip setuptools
+    for util in ${_py3_utils[@]}; do
+        PYENV_VERSION='utils' pip install --upgrade $util
+    done
+
+    # Create a virtualenv based off the latest Python version for interactive usage
+    echo "Installing/updating the default/interactive Python environment"
+    pyenv virtualenv $_py3_versions[1] 'interactive'
+    pyenv rehash  # needed on a first install
+    PYENV_VERSION='interactive' pip install --upgrade pip setuptools
+    # Install some tools to make interactive usage nicer
+    PYENV_VERSION='interactive' pip install --upgrade black bpython ipython
+
+    # Put all Python binaries/virtualenvs and the utilities on the $PATH
+    pyenv global 'interactive' $_py3_versions 'utils' $_py2_version
+}
+
+
+
 # =============================
 # Automate the update machinery
 # =============================
@@ -280,6 +387,21 @@ _update_zplug() {
 }
 
 
+_update_python() {
+    echo 'Updating the Python tool chain'
+
+    if _command_exists pyenv; then
+        pyenv update
+        create-or-update-python-envs
+    fi
+
+    if _command_exists zsh-pip-cache-packages; then
+        zsh-pip-clear-cache
+        zsh-pip-cache-packages
+    fi
+}
+
+
 run-private-scripts() {  # in the Nextcloud
     if [ -d "$HOME/data/getraenkemarkt/shell" ]; then
         for file in $HOME/data/getraenkemarkt/shell/*.sh; do
@@ -298,6 +420,7 @@ update-machine() {
     _command_exists snap && sudo snap refresh && _remove_old_snaps
     _update_repositories
     _update_zsh
+    _update_python
 
     sudo --reset-timestamp
 }

.profile

@@ -11,6 +11,10 @@ export REPOS="$HOME/repos"
 
 export LESSHISTFILE="$HOME/.lesshst"
 
+export PYENV_ROOT="$HOME/.pyenv"
+# No need for *.pyc files on a dev machine
+export PYTHONDONTWRITEBYTECODE=1
+
 export PSQLRC="$HOME/.psqlrc"
 
 
@@ -26,6 +30,7 @@ prepend-to-path () {  # if not already there
 
 prepend-to-path "$HOME/bin"
 prepend-to-path "$HOME/.local/bin"
+prepend-to-path "$PYENV_ROOT/bin"
 
 
 

.zshrc

@@ -5,6 +5,12 @@
 [[ $- != *i* ]] && return
 
 
+# Check if a command can be found on the $PATH
+_command_exists() {
+    command -v "$1" 1>/dev/null 2>&1
+}
+
+
 
 # Enable Powerlevel10k instant prompt
 if [ -r "${XDG_CACHE_HOME:-$HOME/.cache}/zsh/p10k-instant-prompt-${(%):-%n}.zsh" ]; then
@@ -61,7 +67,10 @@ plugins=(
     dirhistory
     dotenv             # config in ~/.zshenv; `_update_repositories` temporarily disables this
     git-escape-magic
+    invoke             # completions for invoke
     jsontools
+    pip                # completions for pip
+    poetry             # completions for poetry
     z
 )
 
@@ -124,6 +133,21 @@ zstyle ':completion:*:warnings' format 'No matches for: %d'
 zstyle ':completion:*' group-name ''
 
 
+# Enable completions for various tools
+
+# invoke -> see plugins above; alternatively use
+# _command_exists invoke && eval "$(invoke --print-completion-script=zsh)"
+
+_command_exists nox && eval "$(register-python-argcomplete nox)"
+
+# pip -> see plugins above; alternatively use
+# _command_exists pip && eval "$(pip completion --zsh)"
+
+_command_exists pipx && eval "$(register-python-argcomplete pipx)"
+
+# poetry -> see plugins above; no alternative here
+
+
 
 # Define key bindings
 

README.md

@@ -24,3 +24,22 @@ Further, `zsh` is set up
 Otherwise, `~/.profile` is probably *not* sourced.
 
 **Important**: Don't forget to back up your current dotfiles!
+
+
+### Python Development Environments
+
+The develop environments for Python are managed via [`pyenv`](https://github.com/pyenv/pyenv).
+
+To set them up, run:
+
+```bash
+create-or-update-python-envs
+```
+
+Several Python versions are installed.
+Additionally, two `virtualenv`s, called "interactive" and "utils", are also created:
+ - "interactive" is the default environment, and
+ - "utils" hosts globally available utilities
+   (e.g., [youtube-dl](https://github.com/ytdl-org/youtube-dl/)).
+
+Use `pyenv local ...` to specify a particular Python binary for a project.