terracotta/neat/config.py
2012-10-01 18:46:18 +10:00

125 lines
3.6 KiB
Python

# Copyright 2012 Anton Beloglazov
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
""" A set of functions for reading configuration options from files.
"""
from contracts import contract
import os
import ConfigParser
import logging
log = logging.getLogger(__name__)
# This is the default config, which should not be modified
DEFAILT_CONFIG_PATH = os.path.join(os.path.dirname(__file__),
'..',
'neat.conf')
# This is the custom config, which may override the defaults
CONFIG_PATH = "/etc/neat/neat.conf"
# The following value is used for testing purposes
#CONFIG_PATH = os.path.join(os.path.dirname(__file__),
# '..',
# 'neat.conf')
# These fields must present in the configuration file
REQUIRED_FIELDS = [
'log_directory',
'log_level',
'sql_connection',
'os_admin_tenant_name',
'os_admin_user',
'os_admin_password',
'os_auth_url',
'compute_hosts',
'global_manager_host',
'global_manager_port',
'local_data_directory',
'local_manager_interval',
'data_collector_interval',
'data_collector_data_length',
'compute_user',
'compute_password',
'sleep_command',
'network_migration_bandwidth',
'algorithm_underload_detection_factory',
'algorithm_underload_detection_parameters',
'algorithm_overload_detection_factory',
'algorithm_overload_detection_parameters',
'algorithm_vm_selection_factory',
'algorithm_vm_selection_parameters',
'algorithm_vm_placement_factory',
'algorithm_vm_placement_parameters',
]
@contract
def read_config(paths):
""" Read the configuration files and return the options.
:param paths: A list of required configuration file paths.
:type paths: list(str)
:return: A dictionary of the configuration options.
:rtype: dict(str: str)
"""
configParser = ConfigParser.ConfigParser()
for path in paths:
configParser.read(path)
return dict(configParser.items("DEFAULT"))
@contract
def validate_config(config, required_fields):
""" Check that the config contains all the required fields.
:param config: A config dictionary to check.
:type config: dict(str: str)
:param required_fields: A list of required fields.
:type required_fields: list(str)
:return: Whether the config is valid.
:rtype: bool
"""
for field in required_fields:
if not field in config:
return False
return True
@contract
def read_and_validate_config(paths, required_fields):
""" Read the configuration files, validate and return the options.
:param paths: A list of required configuration file paths.
:type paths: list(str)
:param required_fields: A list of required fields.
:type required_fields: list(str)
:return: A dictionary of the configuration options.
:rtype: dict(str: str)
"""
config = read_config(paths)
if not validate_config(config, required_fields):
message = 'The config dictionary does not contain ' + \
'all the required fields'
log.critical(message)
raise KeyError(message)
return config