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MG-MW/dotenv.py

Created October 6, 2025 11:52
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#dotenv as optional install
Raw
dotenv.py
"""Check, if option dotenv dependency is installed and not skipped by user.
This is modified from
https://github.com/pallets/flask/blob/2c1b30d0503cfb064f1cb252e6614a06915a362a/src/flask/helpers.py#L36
get_load_dotenv
and
https://github.com/pallets/flask/blob/2c1b30d0503cfb064f1cb252e6614a06915a362a/src/flask/cli.py#L706
load_dotenv
Copyright 2010 Pallets
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. Neither the name of the copyright holder nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""
import os
from pathlib import Path
from app.constants import APPLICATION_ENV_PREFIX
def get_load_dotenv(default: bool = True) -> bool: # noqa: FBT001, FBT002
"""Check whether user has disabled loading default dotenv files.
Environment variable `APP_NAME__SKIP_DOTENV` is checked.
Args:
default: What to return if the env var isn't set.
"""
expected_prefix = "APP_NAME__"
if not expected_prefix == APPLICATION_ENV_PREFIX:
raise ValueError(
f"Aplication env prefix does not match expected {expected_prefix}. "
"Was the env prefix changed? If so, please adjust the doc string."
)
val = os.environ.get(f"{APPLICATION_ENV_PREFIX}SKIP_DOTENV")
if val is None:
return default
return val.casefold() in ("0", "false", "no")
def load_dotenv(path: str | os.PathLike[str] | None = None, *, load_defaults: bool = True) -> bool:
"""Load "dotenv" files to set environment variables.
A given path takes precedence over `.env`. After
loading and combining these files, values are only set if the key is not
already set in `os.environ`.
This is a no-op if `python-dotenv`_ is not installed.
`python-dotenv`: https://github.com/theskumar/python-dotenv#readme
Args:
path: Load the file at this location.
load_defaults: Search for and load the default `.env` file.
Returns:
`True` if at least one env var was loaded.
"""
try:
import dotenv
except ImportError:
if path or Path(".env").is_file():
print(
" * Tip: There are .env files present. Install python-dotenv to use them.",
)
return False
data: dict[str, str | None] = {}
if load_defaults:
default_env_files = (".env",)
for default_name in default_env_files:
if not (default_path := dotenv.find_dotenv(default_name, usecwd=True)):
continue
data |= dotenv.dotenv_values(default_path, encoding="utf-8")
if path is not None and Path(path).is_file():
data |= dotenv.dotenv_values(path, encoding="utf-8")
for key, value in data.items():
if key in os.environ or value is None:
continue
os.environ[key] = value
return bool(data)
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