# Copyright (c) 2016 Cyso < development [at] cyso . com >
#
# This file is part of omniconf, a.k.a. python-omniconf .
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 3.0 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library. If not, see
# <http://www.gnu.org/licenses/>.
from __future__ import absolute_import
from omniconf.backends.generic import ConfigBackend
from omniconf.keys import join_key
import os
[docs]class EnvBackend(ConfigBackend):
"""
Uses the current process Environment, and allows values in it to
be retrieved using dotted keys with a specific prefix. By default no
prefix is assumed.
"""
def __init__(self, conf=None, prefix=None):
super(EnvBackend, self).__init__()
self.prefix = prefix if prefix else ""
[docs] def get_value(self, setting):
"""
Retrieves the value for the given :class:`.Setting`. Keys are converted
as follows:
* Dots are replaced by underscores
* The key is uppercased.
* A prefix is attached to the key
This means that a key like section.value will be queried like
``PREFIX_SECTION_VALUE``. When no prefix is specified,
``SECTION_VALUE`` is queried instead.
"""
_key = setting.key.replace(".", "_").upper()
if self.prefix:
_key = "{0}_{1}".format(self.prefix, _key)
return os.environ[_key]