Example of wrapping a nested JSON config object in a simple python object that allows dynamic object.attr style access to the data elements

pythonic_config.py

#!/usr/bin/env python
"""
example of using a simple python object to wrap a JSON
configuration mapping so that it can be accessed as
a python style object using conf.attr1.attr2.value

"""

CONF = {
    "CREDENTIALS": {
        "SARNIE": {"password": "womp", "username": "derp"},
        "JCOUNTS": {
            "SUCCESS": {"success": True},
        },
    }
}


class ConfigMissing(Exception):
    """
    Exception class to indicate a missing configuration element

    """
    pass


class ConfigElement(object):
    """
    object that uses __getattr__ to allow python object.name
    style access to the dictionary that it wraps and
    keeps track of nested names to allow for easier debugging
    of missing configuration elements

    """
    def __init__(self, conf_ref, name):
        self.conf = conf_ref
        self.name = name

    def __repr__(self):
        return "ConfigElement({})".format(self.name)

    def __getattr__(self, name):
        """
        override getattr to look for the name in
        the configuration. If the element is a dictionary
        then that is wrapped in a new ConfigElement instance
        and returned.
        If the element name is not found, a ConfigMissing
        exception is raised, otherwise the value is returned

        """
        new_name = ".".join([self.name, name])
        conf_item = self.conf.get(name, ConfigMissing(new_name))
        if isinstance(conf_item, dict):
            return ConfigElement(conf_item, new_name)
        if isinstance(conf_item, ConfigMissing):
            raise conf_item
        return conf_item



c = ConfigElement(CONF, 'CONF')
print c.CREDENTIALS
print c.CREDENTIALS.SARNIE
print c.CREDENTIALS.SARNIE.password
print c.CREDENTIALS.JCOUNTS.SUCCESS.success
print c.CREDENTIALS.JCOUNTS.SUCCESS.failure

Thank you