Makefile 'init' target for setting up a virtual python environment (using pyenv)

Makefile

# automatically initialise a local python env
# requires: 
# - pyenv installed (see https://github.com/pyenv/pyenv)
# - ./requirements.txt to manage dependencies via pip

PYENV_VERSION:="3.7.2"

all: init

.PHONY: clean
clean:
	@echo "Cleaning files"
	@find . -name "*.pyc" -type f -exec rm -f '{}' \;
	@find . -name "__pycache__" -type d -prune -exec rm -rf '{}' \;
	@find . -name ".pytest_cache" -type d -prune -exec rm -rf {} \;
	@rm -rf ./.tox
	@rm -f ./.coverage

.PHONY: init
init:
	@echo "Initialising local python dev environment"
	@echo "Checking required python version manager (pyenv)"
	@if ! type 'pyenv' > /dev/null 2>&1; then echo 'Error: pyenv missing (on OSX run "brew install pyenv")'; exit 1; fi
	@echo "${PYENV_VERSION}" > .python-version; fi
	@echo "Ensure required python version `pyenv local` (specified in file ./.python-version) is installed:"
	@pyenv install -s
	@if [ -f ./.venv/bin/python ] && [ "$(./.venv/bin/python --version)" != "Python `pyenv local`" ]; then \
		echo '.venv version '`./.venv/bin/python --version`' does not match version '`pyenv local`' required in .python-version: reinstalling .venv...'; \
		rm -rf .venv; \
	else \
		echo 'OK'; \
	fi;
	@if [ ! -f ./.venv/bin/python ]; then \
		echo "Create virtual environment .venv"; \
		eval "`pyenv which python` -m venv .venv"; \
	fi
	@echo "Virtual environment installed into ./.venv with python version `pyenv local`"
	@echo "Installing requirements"; \
		./.venv/bin/python -m pip install --upgrade pip 1>/dev/null; \
		./.venv/bin/python -m pip install -r requirements.txt 1>/dev/null; \
		if [ -f test-requirements.txt ]; then ./.venv/bin/python -m pip install -r test-requirements.txt 1>/dev/null; fi
	@echo "init complete"
	@echo "IMPORTANT: Dont forget to run 'source ./.venv/bin/activate' to activate the local python environment!"