Create Python virtual environments

gist.sh

venv() {
    PYTHON_2_COMMAND="/usr/local/bin/virtualenv -p python .venv"
    PYTHON_3_COMMAND="/usr/local/bin/python3 -m venv .venv"

    # Was the Python version defined in the args?
    if [ -z "$1" ]; then
        # Try to read the Django version from the requirements
        DJANGO_VERSION=(`grep '^Django' requirements.txt | python -c 'import sys; req = sys.stdin.read().strip(); print(req.split(".")[1])'`)

        if (( DJANGO_VERSION > 10 )); then
            echo "Creating a Python 3 virtual environment (read Django version > 10)."
            eval "$PYTHON_3_COMMAND"
        else
            echo "Creating a Python 2 virtual environment (read Django version <= 10)."
            eval "$PYTHON_2_COMMAND"
        fi
    else
        if [ "${1:2}" == 2 ]; then  # Python 2 venv
            echo "Creating a Python 2 virtual environment (manually specified as 2)."
            eval "$PYTHON_2_COMMAND"
        elif [ "$1" == 3 ]; then
            echo "Creating a Python 3 virtual environment (manually specified as 3)."
            eval "$PYTHON_3_COMMAND"
        fi
    fi

    source .venv/bin/activate
    pip install -r requirements.txt
}