Example direnv .envrc for Python projects that manages a local virtualenv that updates automatically when requirements.txt changes

.envrc

#!/bin/bash

VENV_DIR=".venv"

REQUIREMENTS_HASH_FILE="$VENV_DIR/requirements.shasum"
REQUIREMENTS_HASH_FUNC="shasum"
REQUIREMENTS_HASH_VAL=$($REQUIREMENTS_HASH_FUNC requirements.txt | cut -d ' ' -f 1)

function reset_venv() {
    rm -rf "$VENV_DIR"
    python3 -m venv "$VENV_DIR"
    "$VENV_DIR/bin/pip" install -r "requirements.txt"
    echo -n "$REQUIREMENTS_HASH_VAL" > "$REQUIREMENTS_HASH_FILE"
}

if [ ! -f "$REQUIREMENTS_HASH_FILE" ]; then
    echo "setting up new python virtualenv ..."
    reset_venv
elif [ "$(cat $REQUIREMENTS_HASH_FILE)" != "$REQUIREMENTS_HASH_VAL" ]; then
    echo "python requirements changed, rebuilding virtualenv ..."
    echo "(found hash $(cat $REQUIREMENTS_HASH_FILE), want hash $REQUIREMENTS_HASH_VAL)"
    reset_venv
fi

PATH_add "$VENV_DIR/bin"