Add 'insert_auto_ids' support to 'Batch'.

gcloud/datastore/batch.py

@@ -72,6 +72,7 @@ def __init__(self, dataset_id=None, connection=None):
                              'a dataset ID set.')
 
         self._mutation = datastore_pb.Mutation()
+        self._auto_id_entities = []
 
     @property
     def dataset_id(self):
@@ -107,6 +108,30 @@ def mutation(self):
         """
         return self._mutation
 
+    def add_auto_id_entity(self, entity):
+        """Adds an entity to the list of entities to update with IDs.
+
+        When an entity has a partial key, calling ``save()`` adds an
+        insert_auto_id entry in the mutation.  In order to make sure we
+        update the Entity once the transaction is committed, we need to
+        keep track of which entities to update (and the order is
+        important).
+
+        When you call ``save()`` on an entity inside a transaction, if
+        the entity has a partial key, it adds itself to the list of
+        entities to be updated once the transaction is committed by
+        calling this method.
+
+        :type entity: :class:`gcloud.datastore.entity.Entity`
+        :param entity: The entity to be updated with a completed key.
+
+        :raises: ValueError if the entity's key is alread completed.
+        """
+        if not entity.key.is_partial:
+            raise ValueError("Entity has a completed key")
+
+        self._auto_id_entities.append(entity)
+
     def put(self, entity):
         """Remember an entity's state to be saved during ``commit``.
 
@@ -137,6 +162,9 @@ def put(self, entity):
             self.dataset_id, key_pb, properties,
             exclude_from_indexes=exclude, mutation=self.mutation)
 
+        if entity.key.is_partial:
+            self._auto_id_entities.append(entity)
+
     def delete(self, key):
         """Remember a key to be deleted durring ``commit``.
 
@@ -159,7 +187,15 @@ def commit(self):
         however it can be called explicitly if you don't want to use a
         context manager.
         """
-        self.connection.commit(self._dataset_id, self.mutation)
+        response = self.connection.commit(self._dataset_id, self.mutation)
+        # If the back-end returns without error, we are guaranteed that
+        # the response's 'insert_auto_id_key' will match (length and order)
+        # the request's 'insert_auto_id` entities, which are derived from
+        # our '_auto_id_entities' (no partial success).
+        for new_key_pb, entity in zip(response.insert_auto_id_key,
+                                      self._auto_id_entities):
+            new_id = new_key_pb.path_element[-1].id
+            entity.key = entity.key.completed_key(new_id)
 
     def __enter__(self):
         return self

gcloud/datastore/test_batch.py

@@ -46,6 +46,7 @@ def test_ctor_explicit(self):
         self.assertEqual(batch.dataset_id, _DATASET)
         self.assertEqual(batch.connection, connection)
         self.assertTrue(isinstance(batch.mutation, Mutation))
+        self.assertEqual(batch._auto_id_entities, [])
 
     def test_ctor_implicit(self):
         from gcloud._testing import _Monkey
@@ -62,6 +63,28 @@ def test_ctor_implicit(self):
         self.assertEqual(batch.dataset_id, DATASET_ID)
         self.assertEqual(batch.connection, CONNECTION)
         self.assertTrue(isinstance(batch.mutation, Mutation))
+        self.assertEqual(batch._auto_id_entities, [])
+
+    def test_add_auto_id_entity_w_partial_key(self):
+        _DATASET = 'DATASET'
+        connection = _Connection()
+        batch = self._makeOne(dataset_id=_DATASET, connection=connection)
+        entity = _Entity()
+        key = entity.key = _Key(_Entity)
+        key._partial = True
+
+        batch.add_auto_id_entity(entity)
+
+        self.assertEqual(batch._auto_id_entities, [entity])
+
+    def test_add_auto_id_entity_w_completed_key(self):
+        _DATASET = 'DATASET'
+        connection = _Connection()
+        batch = self._makeOne(dataset_id=_DATASET, connection=connection)
+        entity = _Entity()
+        entity.key = _Key(_Entity)
+
+        self.assertRaises(ValueError, batch.add_auto_id_entity, entity)
 
     def test_put_entity_wo_key(self):
         _DATASET = 'DATASET'
@@ -70,7 +93,23 @@ def test_put_entity_wo_key(self):
 
         self.assertRaises(ValueError, batch.put, _Entity())
 
-    def test_put_entity_w_key(self):
+    def test_put_entity_w_partial_key(self):
+        _DATASET = 'DATASET'
+        _PROPERTIES = {'foo': 'bar'}
+        connection = _Connection()
+        batch = self._makeOne(dataset_id=_DATASET, connection=connection)
+        entity = _Entity(_PROPERTIES)
+        key = entity.key = _Key(_DATASET)
+        key._partial = True
+
+        batch.put(entity)
+
+        self.assertEqual(
+            connection._saved,
+            (_DATASET, key._key, _PROPERTIES, (), batch.mutation))
+        self.assertEqual(batch._auto_id_entities, [entity])
+
+    def test_put_entity_w_completed_key(self):
         _DATASET = 'DATASET'
         _PROPERTIES = {'foo': 'bar'}
         connection = _Connection()
@@ -114,6 +153,22 @@ def test_commit(self):
 
         self.assertEqual(connection._committed, (_DATASET, batch.mutation))
 
+    def test_commit_w_auto_id_entities(self):
+        _DATASET = 'DATASET'
+        _NEW_ID = 1234
+        connection = _Connection(_NEW_ID)
+        batch = self._makeOne(dataset_id=_DATASET, connection=connection)
+        entity = _Entity({})
+        key = entity.key = _Key(_DATASET)
+        key._partial = True
+        batch._auto_id_entities.append(entity)
+
+        batch.commit()
+
+        self.assertEqual(connection._committed, (_DATASET, batch.mutation))
+        self.assertFalse(key._partial)
+        self.assertEqual(key._id, _NEW_ID)
+
     def test_as_context_mgr_wo_error(self):
         _DATASET = 'DATASET'
         _PROPERTIES = {'foo': 'bar'}
@@ -154,16 +209,28 @@ def test_as_context_mgr_w_error(self):
 class _CommitResult(object):
 
     def __init__(self, *new_keys):
-        self.insert_auto_id_key = new_keys
+        self.insert_auto_id_key = [_KeyPB(key) for key in new_keys]
+
+
+class _PathElementPB(object):
+
+    def __init__(self, id):
+        self.id = id
+
+
+class _KeyPB(object):
+
+    def __init__(self, id):
+        self.path_element = [_PathElementPB(id)]
 
 
 class _Connection(object):
     _marker = object()
     _committed = _saved = _deleted = None
     _save_result = (False, None)
 
-    def __init__(self):
-        self._commit_result = _CommitResult()
+    def __init__(self, *new_keys):
+        self._commit_result = _CommitResult(*new_keys)
 
     def save_entity(self, dataset_id, key_pb, properties,
                     exclude_from_indexes=(), mutation=None):
@@ -201,3 +268,8 @@ def is_partial(self):
 
     def to_protobuf(self):
         return self._key
+
+    def completed_key(self, new_id):
+        assert self._partial
+        self._id = new_id
+        self._partial = False