mediagoblin/db/util.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011 Free Software Foundation, Inc
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU Affero General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU Affero General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 """
  18 Utilities for database operations.
  19
  20 Some note on migration and indexing tools:
  21
  22 We store information about what the state of the database is in the
  23 'mediagoblin' document of the 'app_metadata' collection.  Keys in that
  24 document relevant to here:
  25
  26  - 'migration_number': The integer representing the current state of
  27    the migrations
  28 """
  29
  30 import copy
  31
  32 # Imports that other modules might use
  33 from pymongo import DESCENDING
  34 from pymongo.errors import InvalidId
  35 from mongokit import ObjectId
  36
  37 from mediagoblin.db.indexes import ACTIVE_INDEXES, DEPRECATED_INDEXES
  38
  39
  40 def add_new_indexes(database, active_indexes=ACTIVE_INDEXES):
  41     """
  42     Add any new indexes to the database.
  43
  44     Returns:
  45       A list of indexes added in form ('collection', 'index_name')
  46     """
  47     indexes_added = []
  48
  49     for collection_name, indexes in active_indexes.iteritems():
  50         collection = database[collection_name]
  51         collection_indexes = collection.index_information().keys()
  52
  53         for index_name, index_data in indexes.iteritems():
  54             if not index_name in collection_indexes:
  55                 # Get a copy actually so we don't modify the actual
  56                 # structure
  57                 index_data = copy.copy(index_data)
  58                 index = index_data.pop('index')
  59                 collection.create_index(
  60                     index, name=index_name, **index_data)
  61
  62                 indexes_added.append((collection_name, index_name))
  63
  64     return indexes_added
  65
  66
  67 def remove_deprecated_indexes(database, deprecated_indexes=DEPRECATED_INDEXES):
  68     """
  69     Remove any deprecated indexes from the database.
  70
  71     Returns:
  72       A list of indexes removed in form ('collection', 'index_name')
  73     """
  74     indexes_removed = []
  75
  76     for collection_name, indexes in deprecated_indexes.iteritems():
  77         collection = database[collection_name]
  78         collection_indexes = collection.index_information().keys()
  79
  80         for index_name, index_data in indexes.iteritems():
  81             if index_name in collection_indexes:
  82                 collection.drop_index(index_name)
  83
  84                 indexes_removed.append((collection_name, index_name))
  85
  86     return indexes_removed