Using cassandra authentication in discovery

Cassandra authentication can be enabled by specifying username and password in
testbed.py. All the services accessing cassandra should use those credentials
Partial-Bug: 1551969

Change-Id: I662b90a1c68822de13c234d3a2500aad778f7518

src/discovery/disc_cassdb.py

@@ -30,7 +30,9 @@ def get_db_info(cls):
         return db_info
     # end get_db_info
 
-    def __init__(self, module, cass_srv_list, config_log, reset_config=False, db_prefix=None):
+    def __init__(self, module, cass_srv_list, config_log, reset_config=False,
+	    db_prefix=None, cass_credential=None):
+
         self._debug = {
             'db_upd_oper_state': 0,
             'db_upd_admin_state': 0,
@@ -44,7 +46,7 @@ def __init__(self, module, cass_srv_list, config_log, reset_config=False, db_pre
 
         super(DiscoveryCassandraClient, self).__init__(
             cass_srv_list, db_prefix, keyspaces, None,
-            config_log, reset_config=reset_config)
+            config_log, reset_config=reset_config, credential=cass_credential)
 
         DiscoveryCassandraClient._disco_cf = self._cf_dict[self._DISCOVERY_CF_NAME]
     #end __init__

src/discovery/disc_server.py

@@ -335,9 +335,14 @@ def get_service_config(self, service_type, item):
     # end
 
     def _db_connect(self, reset_config):
+        cred = None
+        if 'cassandra' in self.cassandra_config.keys():
+            cred = {'username':self.cassandra_config['cassandra']\
+                    ['cassandra_user'],'password':self.cassandra_config\
+                    ['cassandra']['cassandra_password']}
         self._db_conn = DiscoveryCassandraClient("discovery",
             self._args.cassandra_server_list, self.config_log, reset_config,
-            self._args.cluster_id)
+            self._args.cluster_id, cred)
     # end _db_connect
 
     def cleanup(self):