| # confire.conf | |
| # A simple configuration module for Confire | |
| # | |
| # Author: Benjamin Bengfort <[email protected]> | |
| # Created: Tue May 20 22:19:11 2014 -0400 | |
| # | |
| # Copyright (C) 2013 Cobrain Company | |
| # For license information, see LICENSE.txt | |
| # | |
| # ID: conf.py [] [email protected] $ | |
| """ | |
| Confire class for specifying Confire specific optional items via a YAML | |
| configuration file format. The main configuration class provides utilities | |
| for loading the configuration from disk and iterating across all the | |
| settings. Subclasses of the Configuration specify defaults that can be | |
| updated via the configuration files. | |
| General usage: | |
| from confire.conf import settings | |
| mysetting = settings.get('mysetting', default) | |
| You can also get settings via a dictionary like access: | |
| mysetting = settings['mysetting'] | |
| However, this will raise an exception if the setting is not found. | |
| Note: Keys are CASE insensitive | |
| Note: Settings can be modified directly by settings.mysetting = newsetting | |
| however, this is not recommended, and settings should be fetched via the | |
| dictionary-like access. | |
| """ | |
| ########################################################################## | |
| ## Imports | |
| ########################################################################## | |
| import os | |
| import yaml | |
| import warnings | |
| from six import with_metaclass | |
| from .paths import Path | |
| from .descriptors import SettingsMeta | |
| from .exceptions import ImproperlyConfigured, ConfigurationMissing | |
| ########################################################################## | |
| ## Environment helper function | |
| ########################################################################## | |
| def environ_setting(name, default=None, required=True): | |
| """ | |
| Fetch setting from the environment. The bahavior of the setting if it | |
| is not in environment is as follows: | |
| 1. If it is required and the default is None, raise Exception | |
| 2. If it is requried and a default exists, return default | |
| 3. If it is not required and default is None, return None | |
| 4. If it is not required and default exists, return default | |
| """ | |
| if name not in os.environ and default is None: | |
| message = "The {0} ENVVAR is not set.".format(name) | |
| if required: | |
| raise ImproperlyConfigured(message) | |
| else: | |
| warnings.warn(ConfigurationMissing(message)) | |
| return os.environ.get(name, default) | |
| ########################################################################## | |
| ## Paths helper function | |
| ########################################################################## | |
| def path_setting(**kwargs): | |
| """ | |
| Helper function to enable the configuration of paths on the local file | |
| system. By default, this function manages strings in the YAML file: | |
| 1. Expand user (e.g. ~) | |
| 2. Expand vars (e.g. $HOME) | |
| 3. Normalize the path (e.g. .. and . resolution) | |
| 4. If absolute, return the absolute path | |
| If mkdirs is True, then this function will create the directory if it | |
| does not exist. If raises is True, then it will raise an exception if the | |
| directory does not exist. | |
| """ | |
| return Path(**kwargs) | |
| ########################################################################## | |
| ## Configuration Base Class | |
| ########################################################################## | |
| class Configuration(with_metaclass(SettingsMeta, object)): | |
| """ | |
| Base configuration class specifies how configurations should be | |
| handled and provides helper methods for iterating through options and | |
| configuring the base class. | |
| Subclasses should provide defaults for the various configurations as | |
| directly set class level properties. Note, however, that ANY directive | |
| set in a configuration file (whether or not it has a default) will be | |
| added to the configuration. | |
| Example: | |
| class MyConfig(Configuration): | |
| mysetting = True | |
| logpath = "/var/log/myapp.log" | |
| appname = "MyApp" | |
| The configuration is then loaded via the classmethod `load`: | |
| settings = MyConfig.load() | |
| Access to properties is done two ways: | |
| settings['mysetting'] | |
| settings.get('mysetting', True) | |
| Note: None settings are not allowed! | |
| """ | |
| CONF_PATHS = [ | |
| '/etc/confire.yaml', # The global configuration | |
| os.path.expanduser('~/.confire.yaml'), # User specific configuration | |
| os.path.abspath('conf/confire.yaml') # Local directory configuration | |
| ] | |
| @classmethod | |
| def load(klass): | |
| """ | |
| Insantiates the configuration by attempting to load the | |
| configuration from YAML files specified by the CONF_PATH module | |
| variable. This should be the main entry point for configuration. | |
| """ | |
| config = klass() | |
| for path in klass.CONF_PATHS: | |
| if os.path.exists(path): | |
| with open(path, 'r') as conf: | |
| # BUG: NVD-CWE-noinfo Insufficient Information | |
| # config.configure(yaml.load(conf)) | |
| # FIXED: | |
| config.configure(yaml.safe_load(conf)) | |
| return config | |
| def configure(self, conf={}): | |
| """ | |
| Allows updating of the configuration via a dictionary of | |
| configuration terms or a configuration object. Generally speaking, | |
| this method is utilized to configure the object from a JSON or | |
| YAML parsing. | |
| """ | |
| if not conf: return | |
| if isinstance(conf, Configuration): | |
| conf = dict(conf.options()) | |
| for key, value in conf.items(): | |
| opt = self.get(key, None) | |
| if isinstance(opt, Configuration): | |
| opt.configure(value) | |
| else: | |
| setattr(self, key, value) | |
| def options(self): | |
| """ | |
| Returns an iterable of sorted option names in order to loop | |
| through all the configuration directives specified in the class. | |
| """ | |
| keys = self.__class__.__dict__.copy() | |
| keys.update(self.__dict__) | |
| keys = sorted(keys.keys()) | |
| for opt in keys: | |
| val = self.get(opt) | |
| if val is not None: | |
| yield opt, val | |
| def get(self, key, default=None): | |
| """ | |
| Fetches a key from the configuration without raising a KeyError | |
| exception if the key doesn't exist in the config or | |
| ImproperlyConfigured if the key doesn't exist, instead it returns the | |
| default (None). | |
| """ | |
| try: | |
| return self[key] | |
| except (KeyError, ImproperlyConfigured): | |
| return default | |
| def __getitem__(self, key): | |
| """ | |
| Main configuration access method. Performs a case insensitive | |
| lookup of the key on the class, filtering methods and pseudo | |
| private properties. Raises KeyError if not found. Note, this makes | |
| all properties that are uppercase invisible to the options. | |
| """ | |
| key = key.lower() | |
| if hasattr(self, key): | |
| attr = getattr(self, key) | |
| if not callable(attr) and not key.startswith('_'): | |
| return attr | |
| raise KeyError( | |
| "{} has no configuration '{}'".format( | |
| self.__class__.__name__, key | |
| )) | |
| def __repr__(self): | |
| return str(self) | |
| def __str__(self): | |
| s = "" | |
| for opt, val in self.options(): | |
| r = repr(val) | |
| r = " ".join(r.split()) | |
| wlen = 76-max(len(opt),10) | |
| if len(r) > wlen: | |
| r = r[:wlen-3]+"..." | |
| s += "%-10s = %s\n" % (opt, r) | |
| return s[:-1] | |