Separate all db ops from modulestore ops

common/lib/xmodule/xmodule/modulestore/split_migrator.py

@@ -88,7 +88,7 @@ class SplitMigrator(object):
         index_info = self.split_modulestore.get_course_index_info(course_version_locator)
         versions = index_info['versions']
         versions['draft'] = versions['published']
-        self.split_modulestore.update_course_index(course_version_locator, {'versions': versions}, update_versions=True)
+        self.split_modulestore.update_course_index(index_info)
 
         # clean up orphans in published version: in old mongo, parents pointed to the union of their published and draft
         # children which meant some pointers were to non-existent locations in 'direct'

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

@@ -22,5 +22,4 @@ class DefinitionLazyLoader(object):
         Fetch the definition. Note, the caller should replace this lazy
         loader pointer with the result so as not to fetch more than once
         """
-        return self.modulestore.definitions.find_one(
-            {'_id': self.definition_locator.definition_id})
+        return self.modulestore.db_connection.get_definition(self.definition_locator.definition_id)

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

@@ -0,0 +1,116 @@
+"""
+Segregation of pymongo functions from the data modeling mechanisms for split modulestore.
+"""
+import pymongo
+
+class MongoConnection(object):
+    """
+    Segregation of pymongo functions from the data modeling mechanisms for split modulestore.
+    """
+    def __init__(
+        self, db, collection, host, port=27017, tz_aware=True, user=None, password=None, **kwargs
+    ):
+        """
+        Create & open the connection, authenticate, and provide pointers to the collections
+        """
+        self.database = pymongo.database.Database(
+            pymongo.MongoClient(
+                host=host,
+                port=port,
+                tz_aware=tz_aware,
+                **kwargs
+            ),
+            db
+        )
+
+        if user is not None and password is not None:
+            self.database.authenticate(user, password)
+
+        self.course_index = self.database[collection + '.active_versions']
+        self.structures = self.database[collection + '.structures']
+        self.definitions = self.database[collection + '.definitions']
+
+        # every app has write access to the db (v having a flag to indicate r/o v write)
+        # Force mongo to report errors, at the expense of performance
+        # pymongo docs suck but explanation:
+        # http://api.mongodb.org/java/2.10.1/com/mongodb/WriteConcern.html
+        self.course_index.write_concern = {'w': 1}
+        self.structures.write_concern = {'w': 1}
+        self.definitions.write_concern = {'w': 1}
+
+    def get_structure(self, key):
+        """
+        Get the structure from the persistence mechanism whose id is the given key
+        """
+        return self.structures.find_one({'_id': key})
+
+    def find_matching_structures(self, query):
+        """
+        Find the structure matching the query. Right now the query must be a legal mongo query
+        :param query: a mongo-style query of {key: [value|{$in ..}|..], ..}
+        """
+        return self.structures.find(query)
+
+    def insert_structure(self, structure):
+        """
+        Create the structure in the db
+        """
+        self.structures.insert(structure)
+
+    def update_structure(self, structure):
+        """
+        Update the db record for structure
+        """
+        self.structures.update({'_id': structure['_id']}, structure)
+
+    def get_course_index(self, key):
+        """
+        Get the course_index from the persistence mechanism whose id is the given key
+        """
+        return self.course_index.find_one({'_id': key})
+
+    def find_matching_course_indexes(self, query):
+        """
+        Find the course_index matching the query. Right now the query must be a legal mongo query
+        :param query: a mongo-style query of {key: [value|{$in ..}|..], ..}
+        """
+        return self.course_index.find(query)
+
+    def insert_course_index(self, course_index):
+        """
+        Create the course_index in the db
+        """
+        self.course_index.insert(course_index)
+
+    def update_course_index(self, course_index):
+        """
+        Update the db record for course_index
+        """
+        self.course_index.update({'_id': course_index['_id']}, course_index)
+
+    def delete_course_index(self, key):
+        """
+        Delete the course_index from the persistence mechanism whose id is the given key
+        """
+        return self.course_index.remove({'_id': key})
+
+    def get_definition(self, key):
+        """
+        Get the definition from the persistence mechanism whose id is the given key
+        """
+        return self.definitions.find_one({'_id': key})
+
+    def find_matching_definitions(self, query):
+        """
+        Find the definitions matching the query. Right now the query must be a legal mongo query
+        :param query: a mongo-style query of {key: [value|{$in ..}|..], ..}
+        """
+        return self.definitions.find(query)
+
+    def insert_definition(self, definition):
+        """
+        Create the definition in the db
+        """
+        self.definitions.insert(definition)
+
+

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

@@ -1,7 +1,6 @@
 import threading
 import datetime
 import logging
-import pymongo
 import re
 from importlib import import_module
 from path import path
@@ -21,6 +20,7 @@ from .caching_descriptor_system import CachingDescriptorSystem
 from xblock.fields import Scope
 from xblock.runtime import Mixologist
 from bson.objectid import ObjectId
+from xmodule.modulestore.split_mongo.mongo_connection import MongoConnection
 
 log = logging.getLogger(__name__)
 #==============================================================================
@@ -49,7 +49,6 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
     A Mongodb backed ModuleStore supporting versions, inheritance,
     and sharing.
     """
-    # pylint: disable=W0201
     def __init__(self, doc_store_config, fs_root, render_template,
                  default_class=None,
                  error_tracker=null_error_tracker,
@@ -62,44 +61,13 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         super(SplitMongoModuleStore, self).__init__(**kwargs)
         self.loc_mapper = loc_mapper
 
-        def do_connection(
-            db, collection, host, port=27017, tz_aware=True, user=None, password=None, **kwargs
-        ):
-            """
-            Create & open the connection, authenticate, and provide pointers to the collections
-            """
-            self.db = pymongo.database.Database(
-                pymongo.MongoClient(
-                    host=host,
-                    port=port,
-                    tz_aware=tz_aware,
-                    **kwargs
-                ),
-                db
-            )
-
-            if user is not None and password is not None:
-                self.db.authenticate(user, password)
-
-            self.course_index = self.db[collection + '.active_versions']
-            self.structures = self.db[collection + '.structures']
-            self.definitions = self.db[collection + '.definitions']
-
-        do_connection(**doc_store_config)
+        self.db_connection = MongoConnection(**doc_store_config)
+        self.db = self.db_connection.database
 
         # Code review question: How should I expire entries?
         # _add_cache could use a lru mechanism to control the cache size?
         self.thread_cache = threading.local()
 
-
-        # every app has write access to the db (v having a flag to indicate r/o v write)
-        # Force mongo to report errors, at the expense of performance
-        # pymongo docs suck but explanation:
-        # http://api.mongodb.org/java/2.10.1/com/mongodb/WriteConcern.html
-        self.course_index.write_concern = {'w': 1}
-        self.structures.write_concern = {'w': 1}
-        self.definitions.write_concern = {'w': 1}
-
         if default_class is not None:
             module_path, _, class_name = default_class.rpartition('.')
             class_ = getattr(import_module(module_path), class_name)
@@ -138,7 +106,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
                 block['definition'] = DefinitionLazyLoader(self, block['definition'])
         else:
             # Load all descendants by id
-            descendent_definitions = self.definitions.find({
+            descendent_definitions = self.db_connection.find_matching_definitions({
                 '_id': {'$in': [block['definition']
                                 for block in new_module_data.itervalues()]}})
             # turn into a map
@@ -226,7 +194,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
 
         if course_locator.course_id is not None and course_locator.branch is not None:
             # use the course_id
-            index = self.course_index.find_one({'_id': course_locator.course_id})
+            index = self.db_connection.get_course_index(course_locator.course_id)
             if index is None:
                 raise ItemNotFoundError(course_locator)
             if course_locator.branch not in index['versions']:
@@ -241,7 +209,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
 
         # cast string to ObjectId if necessary
         version_guid = course_locator.as_object_id(version_guid)
-        entry = self.structures.find_one({'_id': version_guid})
+        entry = self.db_connection.get_structure(version_guid)
 
         # b/c more than one course can use same structure, the 'course_id' and 'branch' are not intrinsic to structure
         # and the one assoc'd w/ it by another fetch may not be the one relevant to this fetch; so,
@@ -269,7 +237,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         if qualifiers is None:
             qualifiers = {}
         qualifiers.update({"versions.{}".format(branch): {"$exists": True}})
-        matching = self.course_index.find(qualifiers)
+        matching = self.db_connection.find_matching_course_indexes(qualifiers)
 
         # collect ids and then query for those
         version_guids = []
@@ -279,7 +247,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
             version_guids.append(version_guid)
             id_version_map[version_guid] = structure['_id']
 
-        course_entries = self.structures.find({'_id': {'$in': version_guids}})
+        course_entries = self.db_connection.find_matching_structures({'_id': {'$in': version_guids}})
 
         # get the block for the course element (s/b the root)
         result = []
@@ -455,7 +423,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         """
         if course_locator.course_id is None:
             return None
-        index = self.course_index.find_one({'_id': course_locator.course_id})
+        index = self.db_connection.get_course_index(course_locator.course_id)
         return index
 
     # TODO figure out a way to make this info accessible from the course descriptor
@@ -487,7 +455,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
             'edited_on': when the change was made
         }
         """
-        definition = self.definitions.find_one({'_id': definition_locator.definition_id})
+        definition = self.db_connection.get_definition(definition_locator.definition_id)
         if definition is None:
             return None
         return definition['edit_info']
@@ -509,14 +477,14 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
 
         # TODO if depth is significant, it may make sense to get all that have the same original_version
         # and reconstruct the subtree from version_guid
-        next_entries = self.structures.find({'previous_version' : version_guid})
+        next_entries = self.db_connection.find_matching_structures({'previous_version' : version_guid})
         # must only scan cursor's once
         next_versions = [struct for struct in next_entries]
         result = {version_guid: [CourseLocator(version_guid=struct['_id']) for struct in next_versions]}
         depth = 1
         while depth < version_history_depth and len(next_versions) > 0:
             depth += 1
-            next_entries = self.structures.find({'previous_version':
+            next_entries = self.db_connection.find_matching_structures({'previous_version':
                 {'$in': [struct['_id'] for struct in next_versions]}})
             next_versions = [struct for struct in next_entries]
             for course_structure in next_versions:
@@ -537,7 +505,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         course_struct = self._lookup_course(block_locator.version_agnostic())['structure']
         usage_id = block_locator.usage_id
         update_version_field = 'blocks.{}.edit_info.update_version'.format(usage_id)
-        all_versions_with_block = self.structures.find({'original_version': course_struct['original_version'],
+        all_versions_with_block = self.db_connection.find_matching_structures({'original_version': course_struct['original_version'],
             update_version_field: {'$exists': True}})
         # find (all) root versions and build map previous: [successors]
         possible_roots = []
@@ -596,7 +564,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
                 "original_version": new_id,
                 }
             }
-        self.definitions.insert(document)
+        self.db_connection.insert_definition(document)
         definition_locator = DefinitionLocator(new_id)
         return definition_locator
 
@@ -618,7 +586,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
 
         # if this looks in cache rather than fresh fetches, then it will probably not detect
         # actual change b/c the descriptor and cache probably point to the same objects
-        old_definition = self.definitions.find_one({'_id': definition_locator.definition_id})
+        old_definition = self.db_connection.get_definition(definition_locator.definition_id)
         if old_definition is None:
             raise ItemNotFoundError(definition_locator.url())
 
@@ -630,7 +598,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
             old_definition['edit_info']['edited_on'] = datetime.datetime.now(UTC)
             # previous version id
             old_definition['edit_info']['previous_version'] = definition_locator.definition_id
-            self.definitions.insert(old_definition)
+            self.db_connection.insert_definition(old_definition)
             return DefinitionLocator(old_definition['_id']), True
         else:
             return definition_locator, False
@@ -657,7 +625,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         :param course_blocks: the current list of blocks.
         :param category:
         """
-        existing_uses = self.course_index.find({"_id": {"$regex": id_root}})
+        existing_uses = self.db_connection.find_matching_course_indexes({"_id": {"$regex": id_root}})
         if existing_uses.count() > 0:
             max_found = 0
             matcher = re.compile(id_root + r'(\d+)')
@@ -779,11 +747,11 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
                 parent['edit_info']['update_version'] = new_id
         if continue_version:
             # db update
-            self.structures.update({'_id': new_id}, new_structure)
+            self.db_connection.update_structure(new_structure)
             # clear cache so things get refetched and inheritance recomputed
             self._clear_cache(new_id)
         else:
-            self.structures.insert(new_structure)
+            self.db_connection.insert_structure(new_structure)
 
         # update the index entry if appropriate
         if index_entry is not None:
@@ -856,7 +824,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
                     'original_version': definition_id,
                 }
             }
-            self.definitions.insert(definition_entry)
+            self.db_connection.insert_definition(definition_entry)
 
             new_id = ObjectId()
             draft_structure = {
@@ -880,7 +848,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
                     }
                 }
             }
-            self.structures.insert(draft_structure)
+            self.db_connection.insert_structure(draft_structure)
 
             if versions_dict is None:
                 versions_dict = {master_branch: new_id}
@@ -898,20 +866,20 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
                 if block_fields is not None:
                     root_block['fields'].update(block_fields)
                 if definition_fields is not None:
-                    definition = self.definitions.find_one({'_id': root_block['definition']})
+                    definition = self.db_connection.get_definition(root_block['definition'])
                     definition['fields'].update(definition_fields)
                     definition['edit_info']['previous_version'] = definition['_id']
                     definition['edit_info']['edited_by'] = user_id
                     definition['edit_info']['edited_on'] = datetime.datetime.now(UTC)
                     definition['_id'] = ObjectId()
-                    self.definitions.insert(definition)
+                    self.db_connection.insert_definition(definition)
                     root_block['definition'] = definition['_id']
                     root_block['edit_info']['edited_on'] = datetime.datetime.now(UTC)
                     root_block['edit_info']['edited_by'] = user_id
                     root_block['edit_info']['previous_version'] = root_block['edit_info'].get('update_version')
                     root_block['edit_info']['update_version'] = new_id
 
-                self.structures.insert(draft_structure)
+                self.db_connection.insert_structure(draft_structure)
                 versions_dict[master_branch] = new_id
 
         # create the index entry
@@ -926,7 +894,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
             'edited_by': user_id,
             'edited_on': datetime.datetime.now(UTC),
             'versions': versions_dict}
-        self.course_index.insert(index_entry)
+        self.db_connection.insert_course_index(index_entry)
         return self.get_course(CourseLocator(course_id=new_id, branch=master_branch))
 
     def update_item(self, descriptor, user_id, force=False):
@@ -978,7 +946,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
                 'previous_version': block_data['edit_info']['update_version'],
                 'update_version': new_id,
             }
-            self.structures.insert(new_structure)
+            self.db_connection.insert_structure(new_structure)
             # update the index entry if appropriate
             if index_entry is not None:
                 self._update_head(index_entry, descriptor.location.branch, new_id)
@@ -1016,7 +984,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         is_updated = self._persist_subdag(xblock, user_id, new_structure['blocks'], new_id)
 
         if is_updated:
-            self.structures.insert(new_structure)
+            self.db_connection.insert_structure(new_structure)
 
             # update the index entry if appropriate
             if index_entry is not None:
@@ -1115,31 +1083,18 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         '''Deprecated, use update_item.'''
         raise NotImplementedError('use update_item')
 
-    def update_course_index(self, course_locator, new_values_dict, update_versions=False):
+    def update_course_index(self, updated_index_entry):
         """
-        Change the given course's index entry for the given fields. new_values_dict
-        should be a subset of the dict returned by get_course_index_info.
-        It cannot include '_id' (will raise IllegalArgument).
-        Provide update_versions=True if you intend this to replace the versions hash.
+        Change the given course's index entry.
+
         Note, this operation can be dangerous and break running courses.
 
-        If the dict includes versions and not update_versions, it will raise an exception.
-
-        If the dict includes edited_on or edited_by, it will raise an exception
-
         Does not return anything useful.
         """
         # TODO how should this log the change? edited_on and edited_by for this entry
         # has the semantic of who created the course and when; so, changing those will lose
         # that information.
-        if '_id' in new_values_dict:
-            raise ValueError("Cannot override _id")
-        if 'edited_on' in new_values_dict or 'edited_by' in new_values_dict:
-            raise ValueError("Cannot set edited_on or edited_by")
-        if not update_versions and 'versions' in new_values_dict:
-            raise ValueError("Cannot override versions without setting update_versions")
-        self.course_index.update({'_id': course_locator.course_id},
-            {'$set': new_values_dict})
+        self.db_connection.update_course_index(updated_index_entry)
 
     def delete_item(self, usage_locator, user_id, delete_children=False, force=False):
         """
@@ -1182,7 +1137,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
             remove_subtree(usage_locator.usage_id)
 
         # update index if appropriate and structures
-        self.structures.insert(new_structure)
+        self.db_connection.insert_structure(new_structure)
 
         result = CourseLocator(version_guid=new_id)
 
@@ -1204,11 +1159,11 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
 
         :param course_id: uses course_id rather than locator to emphasize its global effect
         """
-        index = self.course_index.find_one({'_id': course_id})
+        index = self.db_connection.get_course_index(course_id)
         if index is None:
             raise ItemNotFoundError(course_id)
         # this is the only real delete in the system. should it do something else?
-        self.course_index.remove(index['_id'])
+        self.db_connection.delete_course_index(index['_id'])
 
     def get_errored_courses(self):
         """
@@ -1296,7 +1251,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
                 block['fields']["children"] = [
                     usage_id for usage_id in block['fields']["children"] if usage_id in original_structure['blocks']
                 ]
-        self.structures.update({'_id': original_structure['_id']}, original_structure)
+        self.db_connection.update_structure(original_structure)
         # clear cache again b/c inheritance may be wrong over orphans
         self._clear_cache(original_structure['_id'])
 
@@ -1379,7 +1334,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
             else:
                 return None
         else:
-            index_entry = self.course_index.find_one({'_id': locator.course_id})
+            index_entry = self.db_connection.get_course_index(locator.course_id)
             is_head = (
                 locator.version_guid is None or
                 index_entry['versions'][locator.branch] == locator.version_guid
@@ -1424,9 +1379,8 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         :param course_locator:
         :param new_id:
         """
-        self.course_index.update(
-            {"_id": index_entry["_id"]},
-            {"$set": {"versions.{}".format(branch): new_id}})
+        index_entry['versions'][branch] = new_id
+        self.db_connection.update_course_index(index_entry)
 
     def _partition_fields_by_scope(self, category, fields):
         """

common/lib/xmodule/xmodule/modulestore/tests/test_split_migrator.py

@@ -59,9 +59,9 @@ class TestMigration(unittest.TestCase):
         dbref = self.loc_mapper.db
         dbref.drop_collection(self.loc_mapper.location_map)
         split_db = self.split_mongo.db
-        split_db.drop_collection(split_db.course_index)
-        split_db.drop_collection(split_db.structures)
-        split_db.drop_collection(split_db.definitions)
+        split_db.drop_collection(self.split_mongo.db_connection.course_index)
+        split_db.drop_collection(self.split_mongo.db_connection.structures)
+        split_db.drop_collection(self.split_mongo.db_connection.definitions)
         # old_mongo doesn't give a db attr, but all of the dbs are the same
         dbref.drop_collection(self.old_mongo.collection)
 

common/lib/xmodule/xmodule/modulestore/tests/test_split_modulestore.py

@@ -1018,41 +1018,29 @@ class TestCourseCreation(SplitModuleTest):
         Test changing the org, pretty id, etc of a course. Test that it doesn't allow changing the id, etc.
         """
         locator = CourseLocator(course_id="GreekHero", branch='draft')
-        modulestore().update_course_index(locator, {'org': 'funkyU'})
+        course_info = modulestore().get_course_index_info(locator)
+        course_info['org'] = 'funkyU'
+        modulestore().update_course_index(course_info)
         course_info = modulestore().get_course_index_info(locator)
         self.assertEqual(course_info['org'], 'funkyU')
 
-        modulestore().update_course_index(locator, {'org': 'moreFunky', 'prettyid': 'Ancient Greek Demagods'})
+        course_info['org'] = 'moreFunky'
+        course_info['prettyid'] = 'Ancient Greek Demagods'
+        modulestore().update_course_index(course_info)
         course_info = modulestore().get_course_index_info(locator)
         self.assertEqual(course_info['org'], 'moreFunky')
         self.assertEqual(course_info['prettyid'], 'Ancient Greek Demagods')
 
-        self.assertRaises(ValueError, modulestore().update_course_index, locator, {'_id': 'funkygreeks'})
-
-        with self.assertRaises(ValueError):
-            modulestore().update_course_index(
-                locator,
-                {'edited_on': datetime.datetime.now(UTC)}
-            )
-        with self.assertRaises(ValueError):
-            modulestore().update_course_index(
-                locator,
-                {'edited_by': 'sneak'}
-            )
-
-        self.assertRaises(ValueError, modulestore().update_course_index, locator,
-                          {'versions': {'draft': self.GUID_D1}})
-
         # an allowed but not necessarily recommended way to revert the draft version
         versions = course_info['versions']
         versions['draft'] = self.GUID_D1
-        modulestore().update_course_index(locator, {'versions': versions}, update_versions=True)
+        modulestore().update_course_index(course_info)
         course = modulestore().get_course(locator)
         self.assertEqual(str(course.location.version_guid), self.GUID_D1)
 
         # an allowed but not recommended way to publish a course
         versions['published'] = self.GUID_D1
-        modulestore().update_course_index(locator, {'versions': versions}, update_versions=True)
+        modulestore().update_course_index(course_info)
         course = modulestore().get_course(CourseLocator(course_id=locator.course_id, branch="published"))
         self.assertEqual(str(course.location.version_guid), self.GUID_D1)
 
@@ -1068,9 +1056,9 @@ class TestCourseCreation(SplitModuleTest):
         self.assertEqual(new_course.location.usage_id, 'top')
         self.assertEqual(new_course.category, 'chapter')
         # look at db to verify
-        db_structure = modulestore().structures.find_one({
-            '_id': new_course.location.as_object_id(new_course.location.version_guid)
-        })
+        db_structure = modulestore().db_connection.get_structure(
+            new_course.location.as_object_id(new_course.location.version_guid)
+        )
         self.assertIsNotNone(db_structure, "Didn't find course")
         self.assertNotIn('course', db_structure['blocks'])
         self.assertIn('top', db_structure['blocks'])