code review fixes

%s are here to stay - I'll need them later for Cassandra queries.
I have no idea how to use celery.five to detect Python version.

celery/backends/new_cassandra.py

@@ -9,7 +9,6 @@
 from __future__ import absolute_import
 
 import sys
-import six
 try:  # pragma: no cover
     import cassandra
 except ImportError:  # pragma: no cover
@@ -55,13 +54,17 @@ class NewCassandraBackend(BaseBackend):
 
         conf = self.app.conf
         self.servers = (servers or
-                        conf.get('CASSANDRA_SERVERS'))
+                        conf.get('CASSANDRA_SERVERS', None))
         self.port = (port or
-                     conf.get('CASSANDRA_PORT'))
+                     conf.get('CASSANDRA_PORT', None))
         self.keyspace = (keyspace or
-                         conf.get('CASSANDRA_KEYSPACE'))
+                         conf.get('CASSANDRA_KEYSPACE', None))
         self.table = (table or
-                      conf.get('CASSANDRA_TABLE'))
+                      conf.get('CASSANDRA_TABLE', None))
+
+        if not self.servers or not self.keyspace or not self.table:
+            raise ImproperlyConfigured('Cassandra backend not configured.')
+
         expires = (entry_ttl or conf.get('CASSANDRA_ENTRY_TTL', None))
 
         if expires is not None:
@@ -71,20 +74,11 @@ class NewCassandraBackend(BaseBackend):
 
         read_cons = conf.get('CASSANDRA_READ_CONSISTENCY') or 'LOCAL_QUORUM'
         write_cons = conf.get('CASSANDRA_WRITE_CONSISTENCY') or 'LOCAL_QUORUM'
-        try:
-            self.read_consistency = getattr(cassandra.ConsistencyLevel,
-                                            read_cons)
-        except AttributeError:
-            self.read_consistency = cassandra.ConsistencyLevel.LOCAL_QUORUM
-        try:
-            self.write_consistency = getattr(cassandra.ConsistencyLevel,
-                                             write_cons)
-        except AttributeError:
-            self.write_consistency = cassandra.ConsistencyLevel.LOCAL_QUORUM
 
-        if not self.servers or not self.keyspace or not self.table:
-            raise ImproperlyConfigured(
-                'Cassandra backend not configured.')
+        self.read_consistency = getattr(cassandra.ConsistencyLevel,
+            read_cons, cassandra.ConsistencyLevel.LOCAL_QUORUM)
+        self.write_consistency = getattr(cassandra.ConsistencyLevel,
+            write_cons, cassandra.ConsistencyLevel.LOCAL_QUORUM)
 
         self._connection = None
         self._session = None
@@ -108,8 +102,10 @@ class NewCassandraBackend(BaseBackend):
                                                          port=self.port)
             self._session = self._connection.connect(self.keyspace)
 
+            # We are forced to do concatenation below, as formatting would
+            # blow up on superficial %s that will be processed by Cassandra
             self._write_stmt = cassandra.query.SimpleStatement(
-                'INSERT INTO '+self.table+' (task_id, status, result,'''
+                'INSERT INTO %s (task_id, status, result,'''
                 ''' date_done, traceback, children) VALUES'''
                 ' (%s, %s, %s, %s, %s, %s) '+self.cqlexpires+';')
             self._write_stmt.consistency_level = self.write_consistency
@@ -151,8 +147,7 @@ class NewCassandraBackend(BaseBackend):
         """Store return value and status of an executed task."""
         self._get_connection(write=True)
 
-        import sys
-        if six.PY3:
+        if sys.version_info >= (3,):
             buf = lambda x: bytes(x, 'utf8')
         else:
             buf = buffer

celery/tests/backends/test_new_cassandra.py

@@ -2,7 +2,6 @@ from __future__ import absolute_import
 from pickle import loads, dumps
 from datetime import datetime
 
-import six
 from celery import states
 from celery.exceptions import ImproperlyConfigured
 from celery.tests.case import (