A script that wraps Python scripts to manage requirements in a virtual environment.

pywrap.sh

#!/bin/bash

# This script wraps Python scripts in a virtual environment.
# It creates a virtual environment if one doesn't exist, installs dependencies,
# and runs the Python script with the same name as this wrapper. This is a hacky
# wrapper meant for your hacky scripts, for serious stuff you should manage
# dependencies seriously.
#
# Usage:
#   1. Create a Python script named foo.py
#   2. Create a symlink to this wrapper named foo
#   3. Run ./foo with any arguments
#
# The script will:
#   - Create a .venv directory if it doesn't exist
#   - Install dependencies from requirements.txt if present
#   - Generate requirements.txt using pipreqs if missing
#   - Run the Python script, forwarding stdin and arguments

set -euo pipefail

PYTHON_SCRIPT="$0.py"
ROOT_DIR="$(dirname "$PYTHON_SCRIPT")"

# Ensure this script is not being run directly
if [ "$(basename "$0")" = "pywrap.sh" ]; then
    echo "This script should not be run directly. It should be symlinked to a Python script."
    exit 1
fi

# Check if the Python script exists
if [ ! -f "$PYTHON_SCRIPT" ]; then
    echo "Python script $PYTHON_SCRIPT does not exist."
    exit 1
fi

# Set the virtual environment's name
VENV_DIR="$ROOT_DIR/.venv"

# Check if the virtual environment already exists
if [ ! -d "$VENV_DIR" ]; then
    python3 -m venv "$VENV_DIR" || { echo "Failed to create virtual environment."; exit 1; }
fi

# Activate the virtual environment
source "$VENV_DIR/bin/activate"

# Quick and dirty check if the dependencies are installed
if [ -f "$ROOT_DIR/requirements.txt" ]; then
    SITE_PACKAGES=$(python -c "import site; print(site.getsitepackages()[0])")
    REQUIREMENTS=$(cat "$ROOT_DIR/requirements.txt" | awk -F'==' '{print tolower($1)}')
    INSTALL=$(cat <(ls "$SITE_PACKAGES") <(ls "$SITE_PACKAGES") <(cat "$ROOT_DIR/requirements.txt" | awk -F'==' '{print tolower($1)}') | sort | uniq -u)
fi

# Install the dependencies if INSTALL is set or if requirements.txt is missing
if [[ "${INSTALL:-}" != "" ]] || [ ! -f "$ROOT_DIR/requirements.txt" ]; then
    command -v pipreqs &> /dev/null || pip install pipreqs &> /dev/null || { echo "Failed to install pipreqs."; exit 1; }
    pipreqs "$ROOT_DIR" --ignore "$VENV_DIR" --mode no-pin --force &> /dev/null || { echo "Failed to generate requirements.txt."; exit 1; }
    pip install -U -r "$ROOT_DIR/requirements.txt" &> /dev/null || { echo "Failed to install dependencies."; exit 1; }
fi

# Run the Python script with forwarded stdin
python "$PYTHON_SCRIPT" "$@" <&0