Simple wrapper around virtualenv activate to set/unset environment variables

activate

# Wrapper around virtualenv activate to set/unset environment variables
#
# Update the location of the virtualenv (VENV_DIR) and the environment variables
# to be set at the end of the script. Then use this script to init the
# virtualenv instead of the virtualenv version:
#
#   $ source activate
#
 
# Virtualenv location
VENV_DIR="$(dirname $BASH_SOURCE)/venv"

# Store origininal env
_get_env()
{
    env | cut -d "=" -f 1 | sort
}

# Activate the virtualenv
source "$VENV_DIR/bin/activate"
 
# Rename original deactivate function and redefine it as a wrapper function
eval "$(echo "orig_deactivate()"; declare -f deactivate | tail -n +2)"

deactivate()
{
    # Deactivate the virtualenv
    orig_deactivate

    # Unset custom environment variables set at the end of the script
    for V in $(comm -13 <(echo "$_ORIG_ENV_VARS") <(echo "$(_get_env)")); do
        unset $V
    done

    # We no longer need this function
    unset deactivate
}
 
# Store existing env vars
_ORIG_ENV_VARS=$(_get_env)
 
# Set custom environment variables
export CUSTOM_VAR="some value"