Add service supervisor

This patch set adds supervisor mechanism for Watcher services
to get ability to track states.

Partially-Implements: blueprint watcher-service-list
Change-Id: Iab1cefb971c79ed27b22b6a5d1bed8698e35f9a4

watcher/decision_engine/rpcapi.py

@@ -48,15 +48,38 @@ class DecisionEngineAPI(service.Service):
 
 class DecisionEngineAPIManager(object):
 
-    API_VERSION = '1.0'
+    @property
+    def service_name(self):
+        return None
 
-    conductor_endpoints = []
-    status_endpoints = [notification_handler.NotificationHandler]
-    notification_endpoints = []
-    notification_topics = []
+    @property
+    def api_version(self):
+        return '1.0'
 
-    def __init__(self):
-        self.publisher_id = CONF.watcher_decision_engine.publisher_id
-        self.conductor_topic = CONF.watcher_decision_engine.conductor_topic
-        self.status_topic = CONF.watcher_decision_engine.status_topic
-        self.api_version = self.API_VERSION
+    @property
+    def publisher_id(self):
+        return CONF.watcher_decision_engine.publisher_id
+
+    @property
+    def conductor_topic(self):
+        return CONF.watcher_decision_engine.conductor_topic
+
+    @property
+    def status_topic(self):
+        return CONF.watcher_decision_engine.status_topic
+
+    @property
+    def notification_topics(self):
+        return []
+
+    @property
+    def conductor_endpoints(self):
+        return []
+
+    @property
+    def status_endpoints(self):
+        return [notification_handler.NotificationHandler]
+
+    @property
+    def notification_endpoints(self):
+        return []