Source code for conf.config_utils

from __future__ import print_function

import os
import json
from logging import getLogger
log = getLogger('config_utils')

[docs]def from_file(fname): try: with open(fname) as buf: conf = json.load(buf) except ValueError as ve: raise Exception('Bad json format on configuration file: "{0}" [{1}]'.format(fname, str(ve))) except EnvironmentError as ee: raise Exception('Cannot read configuration file: {0} [{1}]'.format(fname, ee.strerror)) if not isinstance(conf, dict): raise Exception('Bad format on configuration file: "{0}" [ dictionary object was expected, instead "{1}" was found]'.format(fname, type(conf).__name__)) return conf
[docs]def from_envvar_file(envvar, environ=None): if environ is None: environ = os.environ if envvar not in environ: return {} fname = environ[envvar] return from_file(fname)
[docs]def from_envvars(prefix=None, environ=None, envvars=None, as_json=True): """Load environment variables in a dictionary Values are parsed as JSON. If parsing fails with a ValueError, values are instead used as verbatim strings. :param prefix: If ``None`` is passed as envvars, all variables from ``environ`` starting with this prefix are imported. The prefix is stripped upon import. :param envvars: A dictionary of mappings of environment-variable-names to Flask configuration names. If a list is passed instead, names are mapped 1:1. If ``None``, see prefix argument. :param environ: use this dictionary instead of os.environ; this is here mostly for mockability :param as_json: If False, values will not be parsed as JSON first. """ conf = {} if environ is None: environ = os.environ if prefix is None and envvars is None: raise RuntimeError('Must either give prefix or envvars argument') # if it's a list, convert to dict if isinstance(envvars, list): envvars = {k: k for k in envvars} if not envvars: envvars = {k: k[len(prefix):] for k in environ.keys() if k.startswith(prefix)} for env_name, name in envvars.items(): if env_name not in environ: continue if as_json: try: conf[name] = json.loads(environ[env_name]) except ValueError: conf[name] = environ[env_name] else: conf[name] = environ[env_name] return conf
[docs]def load_configs(envvar_prefix, path=None): '''Load configuration The following steps will be undertake: * It will attempt to load configs from file: if `path` is provided, it will be used, otherwise the path will be taken from envvar `envvar_prefix` + "SETTINGS". * all envvars starting with `envvar_prefix` will be loaded. ''' conf = {} if path: conf.update(from_file(path)) else: conf.update(from_envvar_file(envvar_prefix + "SETTINGS")) conf.update(from_envvars(prefix=envvar_prefix)) return conf