Refactor the base monitoring driver

Refactoring the base monitoring driver to load driver configuration
from a seperate section in the configuration file. This will allow
drivers to load their own configurations freely
Implements: blueprint dr-refactor-monitoring-drivers

Change-Id: Id330e5500f07ff19b7a2f82df236a4e0108668c9
Depends-On: I7fdf27e8f9263625e1fd1e2a34c015eaf4251792

etc/freezer-dr.conf.sample

@@ -224,18 +224,9 @@
 # Driver used to get a status updates of compute nodes (string value)
 #driver = freezer_dr.monitors.drivers.default.driver.StandardDriver
 
-# username to be used to initialize the monitoring driver (string value)
-#username = <None>
-
-# Password to be used for initializing monitoring driver (string value)
-#password = <None>
-
-# Monitoring system API endpoint (string value)
-#endpoint = <None>
-
-# List of kwargs if you want to pass it to initialize the monitoring driver.
-# should be provided in key:value format (dict value)
-#kwargs =
+# configuration section name. This should contain your monitoring specific
+# configuration options. (string value)
+#backend_name = <None>
 
 
 [notifiers]

freezer_dr/common/config.py

@@ -30,17 +30,9 @@ _MONITORS = [
                default='freezer_dr.monitors.drivers.default.driver.'
                        'StandardDriver',
                help='Driver used to get a status updates of compute nodes'),
-    cfg.StrOpt('username',
-               help='username to be used to initialize the monitoring driver'),
-    cfg.StrOpt('password',
-               help='Password to be used for initializing monitoring driver'),
-    cfg.StrOpt('endpoint',
-               help='Monitoring system API endpoint'),
-    cfg.DictOpt('kwargs',
-                default={},
-                help='List of kwargs if you want to pass it to initialize'
-                ' the monitoring driver. should be provided in key:value '
-                'format')
+    cfg.StrOpt('backend_name',
+               help="configuration section name. This should contain your "
+                    "monitoring specific configuration options.")
 ]
 
 _COMMON = [

freezer_dr/monitors/common/driver.py

@@ -15,6 +15,10 @@
 import abc
 import six
 
+from oslo_config import cfg
+
+CONF = cfg.CONF
+
 
 @six.add_metaclass(abc.ABCMeta)
 class MonitorBaseDriver(object):
@@ -22,22 +26,19 @@ class MonitorBaseDriver(object):
     Abstract class that all monitoring plugins should implement to have a
     unified interface and as many plugins as we want...
     """
+    _OPTS = []
 
-    def __init__(self, username, password, endpoint, **kwargs):
+    def __init__(self, backend_name):
         """
         Initializing the driver. Any monitoring system requires the following
         parameters to call it's api. All these parameters can be passed from the
         configuration file in /etc/freezer/dr.conf
-        :param username: Username
-        :param password: Password
-        :param endpoint: API URL
-        :param kwargs: any additional parameters can be passed using this config
-        option.
+        :param backend_name: Name of section in the configuration file that
+        contains your driver initialization details; like username, password,
+         endpoint and so on. Variables in this section depends on your driver
         """
-        self.username = username
-        self.password = password
-        self.endpoint = endpoint
-        self.kwargs = kwargs
+        CONF.register_opts(self._OPTS, group=backend_name)
+        self.conf = CONF.get(backend_name)
 
     @abc.abstractmethod
     def get_data(self):

freezer_dr/monitors/common/manager.py

@@ -23,12 +23,10 @@ class MonitorManager(object):
 
     def __init__(self):
         monitor = CONF.get('monitoring')
+        backend_name = monitor['backend_name']
         self.driver = importutils.import_object(
-            monitor.get('driver'),
-            monitor.get('username'),
-            monitor.get('password'),
-            monitor.get('endpoint'),
-            **monitor.get('kwargs')
+            monitor.driver,
+            backend_name=backend_name
         )
         driver_info = self.driver.get_info()
         LOG.info('Initializing driver %s with version %s found in %s' %

freezer_dr/monitors/drivers/default/driver.py

@@ -26,17 +26,35 @@ LOG = log.getLogger(__name__)
 
 
 class StandardDriver(MonitorBaseDriver):
+    _OPTS = [
+        cfg.StrOpt('username',
+                   help='username to be used to initialize the default '
+                        'monitoring driver'),
+        cfg.StrOpt('password',
+                   help='Password to be used for initializing the default '
+                        'monitoring driver'),
+        cfg.StrOpt('endpoint',
+                   help='Monitoring system API endpoint'),
+        cfg.DictOpt('kwargs',
+                    default={},
+                    help='List of kwargs if you want to pass it to initialize'
+                         ' the monitoring driver. should be provided in'
+                         ' key:value format'),
+    ]
 
-    def __init__(self, username, password, endpoint, **kwargs):
-        super(StandardDriver, self).__init__(username, password, endpoint, **kwargs)
+    def __init__(self, backend_name):
+        super(StandardDriver, self).__init__(backend_name=backend_name)
+        self.endpoint = self.conf.endpoint
         client = OSClient(
-            authurl=endpoint,
-            username=username,
-            password=password,
-            **kwargs
+            authurl=self.conf.endpoint,
+            username=self.conf.username,
+            password=self.conf.password,
+            **self.conf.kwargs
         )
         LOG.info("OSClient:: username: %s, password: %s, endpoint: %s, kwargs:"
-                 " %s" % (username, '****', endpoint, kwargs))
+                 " %s" % (self.conf.username, '****', self.conf.endpoint,
+                          self.conf.kwargs)
+                 )
         self.client = client
 
     def get_data(self):