Simple Virtualenv Auto Activation With ZSH.

⌚ 🔖 linux 

Since I moved from fish to zsh, one of the main things I missed was virtualfish. I’m not sure how any serious python developer lives without auto activation, as in automatically activating the virtualenv for your project when you open a terminal or cd to it.

Here is a script you can use to achieve auto activation. It doesn’t require virtualenvwrapper, pyenv, or anything like that. Just use python3’s built in python -m venv to create a virtualenv in ~/.virtualenvs/, use the provived venvconnect function to connect the activated env with the current directory, and you’re done.

#!/bin/zsh
#
# Auto activate a python virtualenv when entering the project directory.
# Installation:
#   source virtualenv-auto-activate.sh
#
# Usage:
#   Function `venvconnect`:
#       Connect the currently activated virtualenv to the current directory.
#
VENV_HOME=$HOME/.virtualenvs

function _virtualenv_auto_activate() {
    if [[ -f ".venv" ]]; then
        _VENV_PATH=$VENV_HOME/$(cat .venv)

        # Check to see if already activated to avoid redundant activating
        if [[ "$VIRTUAL_ENV" != $_VENV_PATH ]]; then
            source $_VENV_PATH/bin/activate
        fi
    fi
}

function venvconnect (){
    if [[ -n $VIRTUAL_ENV ]]; then
        echo $(basename $VIRTUAL_ENV) > .venv
    else
        echo "Activate a virtualenv first"
    fi
}

chpwd_functions+=(_virtualenv_auto_activate)
precmd_functions=(_virtualenv_auto_activate $precmd_functions)

Source the above script in your ~/.zshrc and you should get auto activation of python virtualenvs.