def _get_token_from_file(self):
        token = None
        filename = os.path.realpath(os.path.expanduser(self.credential_file))

        try:
            with open(filename, 'r') as f:
                data = f.read()
            token = json.loads(data)
        except IOError:
            pass
        return token
Get the database configuration values from the cherrypy config.
dataset/ETHPy150Open apache/libcloud/libcloud/common/google.py/GoogleOAuth2Credential._get_token_from_file--crossover with--dataset/ETHPy150Open girder/girder/girder/models/__init__.py/getDbConfig