uncloud-mravi/uncloud/common/settings.py

128 lines
4.3 KiB
Python

import configparser
import logging
import sys
import os
from datetime import datetime
from uncloud.common.etcd_wrapper import Etcd3Wrapper
logger = logging.getLogger(__name__)
class CustomConfigParser(configparser.RawConfigParser):
def __getitem__(self, key):
try:
result = super().__getitem__(key)
except KeyError as err:
raise KeyError(
'Key \'{}\' not found in configuration. Make sure you configure uncloud.'.format(
key
)
) from err
else:
return result
class Settings(object):
def __init__(self, config_key='/uncloud/config/'):
conf_name = 'uncloud.conf'
conf_dir = os.environ.get(
'UCLOUD_CONF_DIR', os.path.expanduser('~/uncloud/')
)
self.config_file = os.path.join(conf_dir, conf_name)
self.config_parser = CustomConfigParser(allow_no_value=True)
self.config_key = config_key
# this is used to cache config from etcd for 1 minutes. Without this we
# would make a lot of requests to etcd which slows down everything.
self.last_config_update = datetime.fromtimestamp(0)
self.read_internal_values()
try:
self.config_parser.read(self.config_file)
except Exception as err:
logger.error('%s', err)
def get_etcd_client(self):
args = tuple()
try:
kwargs = {
'host': self.config_parser.get('etcd', 'url'),
'port': self.config_parser.get('etcd', 'port'),
'ca_cert': self.config_parser.get('etcd', 'ca_cert'),
'cert_cert': self.config_parser.get('etcd', 'cert_cert'),
'cert_key': self.config_parser.get('etcd', 'cert_key'),
}
except configparser.Error as err:
raise configparser.Error(
'{} in config file {}'.format(
err.message, self.config_file
)
) from err
else:
try:
wrapper = Etcd3Wrapper(*args, **kwargs)
except Exception as err:
logger.error(
'etcd connection not successfull. Please check your config file.'
'\nDetails: %s\netcd connection parameters: %s',
err,
kwargs,
)
sys.exit(1)
else:
return wrapper
def read_internal_values(self):
self.config_parser.read_dict(
{
'etcd': {
'file_prefix': '/files/',
'host_prefix': '/hosts/',
'image_prefix': '/images/',
'image_store_prefix': '/imagestore/',
'network_prefix': '/networks/',
'request_prefix': '/requests/',
'user_prefix': '/users/',
'vm_prefix': '/vms/',
}
}
)
def read_config_file_values(self, config_file):
try:
# Trying to read configuration file
with open(config_file, 'r') as config_file_handle:
self.config_parser.read_file(config_file_handle)
except FileNotFoundError:
sys.exit(
'Configuration file {} not found!'.format(config_file)
)
except Exception as err:
logger.exception(err)
sys.exit('Error occurred while reading configuration file')
def read_values_from_etcd(self):
etcd_client = self.get_etcd_client()
if (datetime.utcnow() - self.last_config_update).total_seconds() > 60:
config_from_etcd = etcd_client.get(self.config_key, value_in_json=True)
if config_from_etcd:
self.config_parser.read_dict(config_from_etcd.value)
self.last_config_update = datetime.utcnow()
else:
raise KeyError('Key \'{}\' not found in etcd. Please configure uncloud.'.format(self.config_key))
def __getitem__(self, key):
# Allow failing to read from etcd if we have
# it locally
if key not in self.config_parser.sections():
try:
self.read_values_from_etcd()
except KeyError:
pass
return self.config_parser[key]
settings = Settings()