Python Scripting Tips

This page contains a few useful code snippets and tips for our python scripts.

Load VaRA Config

import os
import sys
import importlib.util
from pathlib import Path


def load_vara_config(rel_path: str) -> 'module':
    ''' Load VaRA config from a given path (relative to this module). '''
    current_dir = os.path.dirname(os.path.abspath(__file__))
    vara_config_file = Path(current_dir) / rel_path

    module_spec = importlib.util.spec_from_file_location("__main__", vara_config_file)
    module = importlib.util.module_from_spec(module_spec)

    old_stdout = sys.stdout
    sys.stdout = open(os.devnull, "w")

    module_spec.loader.exec_module(module)

    sys.stdout.close()
    sys.stdout = old_stdout

    return module


def main() -> None:
    # load vara config dictionary (path relative from this file)
    vara_config = load_vara_config(r'../../.vara-config.py')
    vara_config_dict = vara_config.get_config_variables()

Force minimum python version

import sys


MIN_PYTHON = (3, 11)


def main() -> None:
    if sys.version_info < MIN_PYTHON:
        sys.exit("Python %s.%s or later is required.\n" % MIN_PYTHON)

Temporary directory with ‘with’ statement

import os
import contextlib
import tempfile
import shutil


@contextlib.contextmanager
def cd(newdir, cleanup=lambda: True):
    """ Change into a new directory. """
    prevdir = os.getcwd()
    os.chdir(os.path.expanduser(newdir))
    try:
        yield
    finally:
        os.chdir(prevdir)
        cleanup()


@contextlib.contextmanager
def tempdir():
    """ Create a temp. directory and cd into it. """
    dirpath = tempfile.mkdtemp()
    def cleanup():
        shutil.rmtree(dirpath)
    with cd(dirpath, cleanup):
        yield dirpath


def main() -> None:
    with tempdir() as dirpath:
        # do stuff