Added autoretry_read decorator to methods which use mongo cursor.

PLAT-71

common/lib/xmodule/xmodule/modulestore/mongo/base.py

@@ -526,6 +526,7 @@ class MongoModuleStore(ModuleStoreDraftAndPublished, ModuleStoreWriteBase, Mongo
         connection.drop_database(self.collection.database.proxied_object)
         connection.close()
 
+    @autoretry_read()
     def fill_in_run(self, course_key):
         """
         In mongo some course_keys are used without runs. This helper function returns
@@ -699,6 +700,7 @@ class MongoModuleStore(ModuleStoreDraftAndPublished, ModuleStoreWriteBase, Mongo
         item['location'] = item['_id']
         del item['_id']
 
+    @autoretry_read()
     def _query_children_for_cache_children(self, course_key, items):
         """
         Generate a pymongo in query for finding the items and return the payloads
@@ -803,6 +805,7 @@ class MongoModuleStore(ModuleStoreDraftAndPublished, ModuleStoreWriteBase, Mongo
             for item in items
         ]
 
+    @autoretry_read()
     def get_courses(self, **kwargs):
         '''
         Returns a list of course descriptors.
@@ -934,6 +937,7 @@ class MongoModuleStore(ModuleStoreDraftAndPublished, ModuleStoreWriteBase, Mongo
             for key in ('tag', 'org', 'course', 'category', 'name', 'revision')
         ])
 
+    @autoretry_read()
     def get_items(
             self,
             course_id,

common/lib/xmodule/xmodule/modulestore/split_mongo/split.py

@@ -72,6 +72,7 @@ from xmodule.modulestore.exceptions import InsufficientSpecificationError, Versi
 from xmodule.modulestore import (
     inheritance, ModuleStoreWriteBase, ModuleStoreEnum, BulkOpsRecord, BulkOperationsMixin
 )
+from xmodule.modulestore.mongodb_proxy import autoretry_read
 
 from ..exceptions import ItemNotFoundError
 from .caching_descriptor_system import CachingDescriptorSystem
@@ -775,6 +776,7 @@ class SplitMongoModuleStore(SplitBulkWriteMixin, ModuleStoreWriteBase):
         # add it in the envelope for the structure.
         return CourseEnvelope(course_key.replace(version_guid=version_guid), entry)
 
+    @autoretry_read()
     def get_courses(self, branch, **kwargs):
         '''
         Returns a list of course descriptors matching any given qualifiers.
@@ -2631,6 +2633,7 @@ class SplitMongoModuleStore(SplitBulkWriteMixin, ModuleStoreWriteBase):
         """
         structure['blocks'][block_key] = content
 
+    @autoretry_read()
     def find_courses_by_search_target(self, field_name, field_value):
         """
         Find all the courses which cached that they have the given field with the given value.