PYTHON-299: Adding support for ReadPreference on ReplicaSetConnections for Collection.inline_map_reduce.

Author: samuelclay

pymongo/collection.py

@@ -1120,9 +1120,12 @@ def inline_map_reduce(self, map, reduce, full_response=False, **kwargs):
         .. versionadded:: 1.10
         """
 
+        use_master = not self.slave_okay and not self.read_preference
+
         response = self.__database.command("mapreduce", self.__name,
                                            uuid_subtype=self.__uuid_subtype,
                                            map=map, reduce=reduce,
+                                           _use_master=use_master,
                                            out={"inline": 1}, **kwargs)
 
         if full_response: