Configuration/Setting module added

ucloud/settings/__init__.py

@@ -0,0 +1,86 @@
+import configparser
+import logging
+import sys
+import os
+
+from ucloud.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 config file"\
+                           .format(key)) from err
+        else:
+            return result
+
+
+class Settings(object):
+    def __init__(self, config_key='/uncloud/config/'):
+        conf_name = 'ucloud.conf'
+        conf_dir = os.environ.get('UCLOUD_CONF_DIR', '/etc/ucloud')
+        config_file = os.path.join(conf_dir, conf_name)
+        
+        self.config_parser = CustomConfigParser(allow_no_value=True)
+        self.config_key = config_key
+
+        self.read_internal_values()
+        self.read_config_file_values(config_file)
+
+        self.etcd_wrapper_args = tuple()
+        self.etcd_wrapper_kwargs = {
+            'host':      self.config_parser['etcd']['url'],
+            'port':      self.config_parser['etcd']['port'],
+            'ca_cert':   self.config_parser['etcd']['ca_cert'],
+            'cert_cert': self.config_parser['etcd']['cert_cert'],
+            'cert_key':  self.config_parser['etcd']['cert_key']
+        }
+
+    
+    def get_etcd_client(self):
+        args = self.etcd_wrapper_args
+        kwargs = self.etcd_wrapper_kwargs
+        return Etcd3Wrapper(*args, **kwargs)
+        
+    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()
+        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)
+        else:
+            return
+            sys.exit("No settings found in etcd at key {}".format(self.config_key))
+    
+    def __getitem__(self, key):
+        self.read_values_from_etcd()
+        return self.config_parser[key]