Merge pull request getredash#1482 from yershalom/master

[Cassandra] Add: schema browser support & explicit protocol version

Author: arikfr

query_runner/cass.py

@@ -15,7 +15,7 @@
 
 
 class Cassandra(BaseQueryRunner):
-    noop_query = "SELECT * FROM system.compactions_in_progress"
+    noop_query = "SELECT dateof(now()) FROM system.local"
 
     @classmethod
     def enabled(cls):
@@ -53,23 +53,33 @@ def configuration_schema(cls):
     def type(cls):
         return "Cassandra"
 
-    def _get_tables(self, schema):
+    def get_schema(self, get_stats=False):
         query = """
-        select columnfamily_name from system.schema_columnfamilies where keyspace_name = '{}';
+        SELECT columnfamily_name, column_name FROM system.schema_columns where keyspace_name ='{}';
         """.format(self.configuration['keyspace'])
 
         results, error = self.run_query(query, None)
-        return results, error
+        results = json.loads(results)
+
+        schema = {}
+        for row in results['rows']:
+            table_name = row['columnfamily_name']
+            column_name = row['column_name']
+            if table_name not in schema:
+                schema[table_name] = {'name': table_name, 'columns': []}
+            schema[table_name]['columns'].append(column_name)
+
+        return schema.values()
 
     def run_query(self, query, user):
         connection = None
         try:
             if self.configuration.get('username', '') and self.configuration.get('password', ''):
                 auth_provider = PlainTextAuthProvider(username='{}'.format(self.configuration.get('username', '')),
                                                       password='{}'.format(self.configuration.get('password', '')))
-                connection = Cluster([self.configuration.get('host', '')], auth_provider=auth_provider)
+                connection = Cluster([self.configuration.get('host', '')], auth_provider=auth_provider, protocol_version=3)
             else:
-                connection = Cluster([self.configuration.get('host', '')])
+                connection = Cluster([self.configuration.get('host', '')], protocol_version=3)
 
             session = connection.connect()
             session.set_keyspace(self.configuration['keyspace'])