osm_policy_module/core/config.py

   1 # -*- coding: utf-8 -*-
   2
   3 # Copyright 2018 Whitestack, LLC
   4 # *************************************************************
   5
   6 # This file is part of OSM Monitoring module
   7 # All Rights Reserved to Whitestack, LLC
   8
   9 # Licensed under the Apache License, Version 2.0 (the "License"); you may
  10 # not use this file except in compliance with the License. You may obtain
  11 # a copy of the License at
  12
  13 #         http://www.apache.org/licenses/LICENSE-2.0
  14
  15 # Unless required by applicable law or agreed to in writing, software
  16 # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  17 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  18 # License for the specific language governing permissions and limitations
  19 # under the License.
  20
  21 # For those usages not covered by the Apache License, Version 2.0 please
  22 # contact: bdiaz@whitestack.com or glavado@whitestack.com
  23 ##
  24 """Global configuration managed by environment variables."""
  25
  26 import logging
  27 import os
  28
  29 import pkg_resources
  30 import yaml
  31
  32 logger = logging.getLogger(__name__)
  33
  34
  35 class Config:
  36     def __init__(self, config_file: str = ''):
  37         self.conf = {}
  38         self._read_config_file(config_file)
  39         self._read_env()
  40
  41     def _read_config_file(self, config_file):
  42         if not config_file:
  43             path = 'pol.yaml'
  44             config_file = pkg_resources.resource_filename(__name__, path)
  45         with open(config_file) as f:
  46             self.conf = yaml.load(f)
  47
  48     def get(self, section, field=None):
  49         if not field:
  50             return self.conf[section]
  51         return self.conf[section][field]
  52
  53     def set(self, section, field, value):
  54         if section not in self.conf:
  55             self.conf[section] = {}
  56         self.conf[section][field] = value
  57
  58     def _read_env(self):
  59         for env in os.environ:
  60             if not env.startswith("OSMPOL_"):
  61                 continue
  62             elements = env.lower().split("_")
  63             if len(elements) < 3:
  64                 logger.warning(
  65                     "Environment variable %s=%s does not comply with required format. Section and/or field missing.",
  66                     env, os.getenv(env))
  67                 continue
  68             section = elements[1]
  69             field = '_'.join(elements[2:])
  70             value = os.getenv(env)
  71             if section not in self.conf:
  72                 self.conf[section] = {}
  73             self.conf[section][field] = value