PYTHON-989 - Support write concern in find_and_modify, find_one_and_XXX.

Author: Luke Lovett

pymongo/collection.py

@@ -1797,6 +1797,10 @@ def __find_and_modify(self, filter, projection, sort, upsert=None,
  common.validate_boolean("upsert", upsert)
  cmd["upsert"] = upsert
  with self._socket_for_writes() as sock_info:
+ if sock_info.max_wire_version >= 4 and 'writeConcern' not in cmd:
+ wc_doc = self.write_concern.document
+ if wc_doc:
+ cmd['writeConcern'] = wc_doc
  out = self._command(sock_info, cmd,
  read_preference=ReadPreference.PRIMARY,
  allowable_errors=[_NO_OBJ_ERROR])
@@ -1844,7 +1848,17 @@ def find_one_and_delete(self, filter,
  as keyword arguments (for example maxTimeMS can be used with
  recent server versions).
 
+ .. versionchanged:: 3.2
+ Respects write concern.
+
+ .. warning:: Starting in PyMongo 3.2, this command uses the
+ :class:`~pymongo.write_concern.WriteConcern` of this
+ :class:`~pymongo.collection.Collection` when connected to MongoDB >=
+ 3.2. Note that using an elevated write concern with this command may
+ be slower compared to using the default write concern.
+
  .. versionadded:: 3.0
+
  """
  kwargs['remove'] = True
  return self.__find_and_modify(filter, projection, sort, **kwargs)
@@ -1897,6 +1911,15 @@ def find_one_and_replace(self, filter, replacement,
  as keyword arguments (for example maxTimeMS can be used with
  recent server versions).
 
+ .. versionchanged:: 3.2
+ Respects write concern.
+
+ .. warning:: Starting in PyMongo 3.2, this command uses the
+ :class:`~pymongo.write_concern.WriteConcern` of this
+ :class:`~pymongo.collection.Collection` when connected to MongoDB >=
+ 3.2. Note that using an elevated write concern with this command may
+ be slower compared to using the default write concern.
+
  .. versionadded:: 3.0
  """
  common.validate_ok_for_replace(replacement)
@@ -1983,6 +2006,15 @@ def find_one_and_update(self, filter, update,
  as keyword arguments (for example maxTimeMS can be used with
  recent server versions).
 
+ .. versionchanged:: 3.2
+ Respects write concern.
+
+ .. warning:: Starting in PyMongo 3.2, this command uses the
+ :class:`~pymongo.write_concern.WriteConcern` of this
+ :class:`~pymongo.collection.Collection` when connected to MongoDB >=
+ 3.2. Note that using an elevated write concern with this command may
+ be slower compared to using the default write concern.
+
  .. versionadded:: 3.0
  """
  common.validate_ok_for_update(update)
@@ -2130,14 +2162,17 @@ def find_and_modify(self, query={}, update=None,
  "pairs, a dict of len 1, or an instance of "
  "SON or OrderedDict")
 
-
  fields = kwargs.pop("fields", None)
  if fields is not None:
  kwargs["fields"] = helpers._fields_list_to_dict(fields, "fields")
 
  cmd = SON([("findAndModify", self.__name)])
  cmd.update(kwargs)
  with self._socket_for_writes() as sock_info:
+ if sock_info.max_wire_version >= 4 and 'writeConcern' not in cmd:
+ wc_doc = self.write_concern.document
+ if wc_doc:
+ cmd['writeConcern'] = wc_doc
  out = self._command(sock_info, cmd,
  read_preference=ReadPreference.PRIMARY,
  allowable_errors=[_NO_OBJ_ERROR])

test/test_collection.py

@@ -31,7 +31,7 @@
 from bson.son import SON
 from pymongo import (ASCENDING, DESCENDING, GEO2D,
  GEOHAYSTACK, GEOSPHERE, HASHED, TEXT)
-from pymongo import MongoClient
+from pymongo import MongoClient, monitoring
 from pymongo.collection import Collection, ReturnDocument
 from pymongo.command_cursor import CommandCursor
 from pymongo.cursor import CursorType
@@ -51,7 +51,8 @@
 from pymongo.write_concern import WriteConcern
 from test.test_client import IntegrationTest
 from test.utils import (is_mongos, enable_text_search, get_pool,
- rs_or_single_client, wait_until)
+ rs_or_single_client, single_client,
+ wait_until, EventListener)
 from test import client_context, host, port, unittest
 
 
@@ -1668,6 +1669,77 @@ def test_find_one_and(self):
  {'$inc': {'i': 1}},
  sort=sort)['j'])
 
+ def test_find_one_and_write_concern(self):
+ listener = EventListener()
+ saved_listeners = monitoring._LISTENERS
+ monitoring._LISTENERS = monitoring._Listeners([])
+ db = single_client(event_listeners=[listener])[self.db.name]
+ # non-default WriteConcern.
+ c_w0 = db.get_collection(
+ 'test', write_concern=WriteConcern(w=0))
+ # default WriteConcern.
+ c_default = db.get_collection('test', write_concern=WriteConcern())
+ results = listener.results
+ try:
+ if client_context.version.at_least(3, 1, 9, -1):
+ c_w0.find_and_modify(
+ {'_id': 1}, {'$set': {'foo': 'bar'}})
+ self.assertEqual(
+ {'w': 0}, results['started'][0].command['writeConcern'])
+ results.clear()
+
+ c_w0.find_one_and_update(
+ {'_id': 1}, {'$set': {'foo': 'bar'}})
+ self.assertEqual(
+ {'w': 0}, results['started'][0].command['writeConcern'])
+ results.clear()
+
+ c_w0.find_one_and_replace({'_id': 1}, {'foo': 'bar'})
+ self.assertEqual(
+ {'w': 0}, results['started'][0].command['writeConcern'])
+ results.clear()
+
+ c_w0.find_one_and_delete({'_id': 1})
+ self.assertEqual(
+ {'w': 0}, results['started'][0].command['writeConcern'])
+ results.clear()
+ else:
+ c_w0.find_and_modify(
+ {'_id': 1}, {'$set': {'foo': 'bar'}})
+ self.assertNotIn('writeConcern', results['started'][0].command)
+ results.clear()
+
+ c_w0.find_one_and_update(
+ {'_id': 1}, {'$set': {'foo': 'bar'}})
+ self.assertNotIn('writeConcern', results['started'][0].command)
+ results.clear()
+
+ c_w0.find_one_and_replace({'_id': 1}, {'foo': 'bar'})
+ self.assertNotIn('writeConcern', results['started'][0].command)
+ results.clear()
+
+ c_w0.find_one_and_delete({'_id': 1})
+ self.assertNotIn('writeConcern', results['started'][0].command)
+ results.clear()
+
+ c_default.find_and_modify({'_id': 1}, {'$set': {'foo': 'bar'}})
+ self.assertNotIn('writeConcern', results['started'][0].command)
+ results.clear()
+
+ c_default.find_one_and_update({'_id': 1}, {'$set': {'foo': 'bar'}})
+ self.assertNotIn('writeConcern', results['started'][0].command)
+ results.clear()
+
+ c_default.find_one_and_replace({'_id': 1}, {'foo': 'bar'})
+ self.assertNotIn('writeConcern', results['started'][0].command)
+ results.clear()
+
+ c_default.find_one_and_delete({'_id': 1})
+ self.assertNotIn('writeConcern', results['started'][0].command)
+ results.clear()
+ finally:
+ monitoring._LISTENERS = saved_listeners
+
  def test_find_with_nested(self):
  c = self.db.test
  c.drop()