setV: A Bash function to maintain Python virtual environments

Get to know setV, a lightweight Python virtual environment manager and alternative to virtualenvwrapper.

For more than a year, setV has been hidden away within my bash_scripts project, but it's time for it to become public. setV is a Bash function I use as an alternative to virtualenvwrapper. It provides basic features that enable you to do things such as:

Use Python 3 by default
Create a new virtual environment
Create a new virtual environment using a custom Python path with -p (or --python)
Delete an existing virtual environment
List all existing virtual environment
Use Tab completion (in case you don't remember the virtual environment name)

Installation

To install setV, download the script:

curl https://gitlab.com/psachin/setV/raw/master/install.sh

Review the script, and then run it:

sh ./install.sh

When you install setV, the installation script asks you to source ~/.bashrc or ~/.bash_profile. Be sure to do that.

Usage

The basic command is setv.

Create a virtual environment:

setv --new rango  # setv -n rango

# Or using a custom Python binary path
setv --new --python /opt/python/python3 rango  # setv -n -p /opt/python/python3 rango

Activate an existing environment:

setv VIRTUAL_ENVIRONMENT_NAME

# For example
setv rango

List all virtual environments:

setv --list
# or
setv [TAB] [TAB]

Delete a virtual environment:

setv --delete rango

Switch to another virtual environment:

# Assuming you are in 'rango', switch to 'tango' using
setv tango

Tab Completion

If you don't fully remember the virtual environment's name, Bash-like Tab completion works for virtual environment names.

Get involved

setV is open source under the GNU GPLv3, and contributions are welcome. To learn more, visit the Contribute section of setV's README in its GitLab repository.

The setV script

#!/usr/bin/env bash
# setV - A Lightweight Python virtual environment manager.
# Author: Sachin (psachin) <iclcoolster@gmail.com>
# Author's URL: https://psachin.gitlab.io/about
#
# License: GNU GPL v3, See LICENSE file
#
# Configure(Optional):
# Set `SETV_VIRTUAL_DIR_PATH` value to your virtual environments
# directory-path. By default it is set to '~/virtualenvs/'
#
# Usage:
# Manual install: Added below line to your .bashrc or any local rc script():
# ---
# source /path/to/virtual.sh
# ---
#
# Now you can 'activate' the virtual environment by typing
# $ setv <YOUR VIRTUAL ENVIRONMENT NAME>
#
# For example:
# $ setv rango
#
# or type:
# setv [TAB] [TAB]  (to list all virtual envs)
#
# To list all your virtual environments:
# $ setv --list
#
# To create new virtual environment:
# $ setv --new new_virtualenv_name
#
# To delete existing virtual environment:
# $ setv --delete existing_virtualenv_name
#
# To deactivate, type:
# $ deactivate

# Path to virtual environment directory
SETV_VIRTUAL_DIR_PATH="$HOME/virtualenvs/"
# Default python version to use. This decides whether to use `virtualenv` or `python3 -m venv`
SETV_PYTHON_VERSION=3  # Defaults to Python3
SETV_PY_PATH=$(which python${SETV_PYTHON_VERSION})

function _setvcomplete_()
{
    # Bash-autocompletion.
    # This ensures Tab-auto-completions work for virtual environment names.
    local cmd="${1##*/}" # to handle command(s).
                         # Not necessary as such. 'setv' is the only command

    local word=${COMP_WORDS[COMP_CWORD]} # Words thats being completed
    local xpat='${word}'		 # Filter pattern. Include
					 # only words in variable '$names'
    local names=$(ls -l "${SETV_VIRTUAL_DIR_PATH}" | egrep '^d' | awk -F " " '{print $NF}') # Virtual environment names

    COMPREPLY=($(compgen -W "$names" -X "$xpat" -- "$word")) # compgen generates the results
}

function _setv_help_() {
    # Echo help/usage message
    echo "Usage: setv [OPTIONS] [NAME]"
    echo Positional argument:
    echo -e "NAME                       Activate virtual env."
    echo Optional arguments:
    echo -e "-l, --list                 List all Virtual Envs."
    echo -e "-n, --new NAME             Create a new Python Virtual Env."
    echo -e "-d, --delete NAME          Delete existing Python Virtual Env."
    echo -e "-p, --python PATH          Python binary path."
}

function _setv_custom_python_path()
{
    if [ -f "${1}" ];
    then
	if [ "`expr $1 : '.*python\([2,3]\)'`" = "3" ];
	then
	    SETV_PYTHON_VERSION=3
	else
	    SETV_PYTHON_VERSION=2
	fi
	SETV_PY_PATH=${1}
	_setv_create $2
    else
	echo "Error: Path ${1} does not exist!"
    fi
}

function _setv_create()
{
    # Creates new virtual environment if ran with -n|--new flag
    if [ -z ${1} ];
    then
	echo "You need to pass virtual environment name"
	_setv_help_
    else
	echo "Creating new virtual environment with the name: $1"

	if [ ${SETV_PYTHON_VERSION} -eq 3 ];
	then
	    ${SETV_PY_PATH} -m venv ${SETV_VIRTUAL_DIR_PATH}${1}
	else
	    virtualenv -p ${SETV_PY_PATH} ${SETV_VIRTUAL_DIR_PATH}${1}
	fi

	echo "You can now activate the Python virtual environment by typing: setv ${1}"
    fi
}

function _setv_delete()
{
    # Deletes virtual environment if ran with -d|--delete flag
    # TODO: Refactor
    if [ -z ${1} ];
    then
	echo "You need to pass virtual environment name"
	_setv_help_
    else
	if [ -d ${SETV_VIRTUAL_DIR_PATH}${1} ];
	then
	    read -p "Really delete this virtual environment(Y/N)? " yes_no
	    case $yes_no in
		Y|y) rm -rvf ${SETV_VIRTUAL_DIR_PATH}${1};;
		N|n) echo "Leaving the virtual environment as it is.";;
		*) echo "You need to enter either Y/y or N/n"
	    esac
	else
	    echo "Error: No virtual environment found by the name: ${1}"
	fi
    fi
}

function _setv_list()
{
    # Lists all virtual environments if ran with -l|--list flag
    echo -e "List of virtual environments you have under ${SETV_VIRTUAL_DIR_PATH}:\n"
    for virt in $(ls -l "${SETV_VIRTUAL_DIR_PATH}" | egrep '^d' | awk -F " " '{print $NF}')
    do
	echo ${virt}
    done
}

function setv() {
    # Main function
    if [ $# -eq 0 ];
    then
	_setv_help_
    elif [ $# -le 3 ];
    then
	case "${1}" in
	    -n|--new) _setv_create ${2};;
	    -d|--delete) _setv_delete ${2};;
	    -l|--list) _setv_list;;
	    *) if [ -d ${SETV_VIRTUAL_DIR_PATH}${1} ];
	       then
		   # Activate the virtual environment
		   source ${SETV_VIRTUAL_DIR_PATH}${1}/bin/activate
	       else
		   # Else throw an error message
		   echo "Sorry, you don't have any virtual environment with the name: ${1}"
		   _setv_help_
	       fi
	       ;;
	esac
    elif [ $# -le 5 ];
    then
	case "${2}" in
	    -p|--python) _setv_custom_python_path ${3} ${4};;
	    *) _setv_help_;;
	esac
    fi
}

# Calls bash-complete. The compgen command accepts most of the same
# options that complete does but it generates results rather than just
# storing the rules for future use.
complete  -F _setvcomplete_ setv