#!/usr/bin/env python
# cardinal_pythonlib/sysops.py
"""
===============================================================================
Original code copyright (C) 2009-2022 Rudolf Cardinal (rudolf@pobox.com).
This file is part of cardinal_pythonlib.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
https://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
===============================================================================
**Simple system operations.**
"""
import logging
import os
import sys
from typing import NoReturn
log = logging.getLogger(__name__)
EXIT_FAILURE = 1
EXIT_SUCCESS = 0
[docs]def die(
msg: str, log_level: int = logging.CRITICAL, exit_code: int = EXIT_FAILURE
) -> NoReturn:
"""
Prints a message and hard-exits the program.
Args:
msg: message
log_level: log level to use
exit_code: exit code (errorlevel)
"""
log.log(level=log_level, msg=msg)
sys.exit(exit_code)
[docs]def get_envvar_or_die(
envvar: str,
log_level: int = logging.CRITICAL,
exit_code: int = EXIT_FAILURE,
) -> str:
"""
Returns the value of an environment variable.
If it is unset or blank, complains and hard-exits the program.
Args:
envvar: environment variable name
log_level: log level to use for failure
exit_code: exit code (errorlevel) for failure
Returns:
str: the value of the environment variable
"""
value = os.environ.get(envvar)
if not value:
die(
f"Must set environment variable {envvar}",
log_level=log_level,
exit_code=exit_code,
)
return value