def test_eventual_read_doesnt_update_memcache(self):
entity_data = {"field1": "Apple", "comb1": 1, "comb2": "Cherry"}
identifiers = caching._apply_namespace(
unique_utils.unique_identifiers_from_entity(
CachingTestModel, FakeEntity(entity_data, id=222)),
DEFAULT_NAMESPACE,
)
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
instance = CachingTestModel.objects.create(id=222, **entity_data)
instance.refresh_from_db() # Add to memcache (consistent Get)
for identifier in identifiers:
self.assertEqual(entity_data, cache.get(identifier))
cache.clear()
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
CachingTestModel.objects.all()[0] # Inconsistent read
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
def test_save_caches_outside_transaction_only(self):
entity_data = {"field1": "Apple", "comb1": 1, "comb2": "Cherry"}
identifiers = caching._apply_namespace(
unique_utils.unique_identifiers_from_entity(
CachingTestModel, FakeEntity(entity_data, id=222)),
DEFAULT_NAMESPACE,
)
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
instance = CachingTestModel.objects.create(id=222, **entity_data)
instance.refresh_from_db()
for identifier in identifiers:
self.assertEqual(entity_data, cache.get(identifier))
instance.delete()
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
with transaction.atomic():
instance = CachingTestModel.objects.create(**entity_data)
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
def test_transactional_save_wipes_the_cache_only_after_its_result_is_consistently_available(
self):
entity_data = {
"field1": "old",
}
identifiers = caching._apply_namespace(
unique_utils.unique_identifiers_from_entity(
CachingTestModel, FakeEntity(entity_data, id=222)),
DEFAULT_NAMESPACE,
)
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
instance = CachingTestModel.objects.create(id=222, **entity_data)
instance.refresh_from_db() # Add to memcache (consistent Get)
for identifier in identifiers:
self.assertEqual("old", cache.get(identifier)["field1"])
@non_transactional
def non_transactional_read(instance_pk):
CachingTestModel.objects.get(pk=instance_pk)
with transaction.atomic():
instance.field1 = "new"
instance.save()
non_transactional_read(
instance.pk) # could potentially recache the old object
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
def test_eventual_read_doesnt_update_memcache(self):
entity_data = {
"field1": "Apple",
"comb1": 1,
"comb2": "Cherry"
}
identifiers = caching._apply_namespace(
unique_utils.unique_identifiers_from_entity(CachingTestModel, FakeEntity(entity_data, id=222)),
DEFAULT_NAMESPACE,
)
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
CachingTestModel.objects.create(id=222, **entity_data)
for identifier in identifiers:
self.assertEqual(entity_data, cache.get(identifier))
cache.clear()
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
CachingTestModel.objects.all()[0] # Inconsistent read
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
def test_save_inside_transaction_evicts_cache(self):
entity_data = {"field1": "Apple", "comb1": 1, "comb2": "Cherry"}
identifiers = caching._apply_namespace(
unique_utils.unique_identifiers_from_entity(
CachingTestModel, FakeEntity(entity_data, id=222)),
DEFAULT_NAMESPACE,
)
instance = CachingTestModel.objects.create(id=222, **entity_data)
instance.refresh_from_db() # Adds to memcache (consistent Get)
for identifier in identifiers:
self.assertEqual(entity_data, cache.get(identifier))
with transaction.atomic():
instance.field1 = "Banana"
instance.save()
# Make sure that altering inside the transaction evicted the item from the cache
# and that a get then hits the datastore (which then in turn caches)
with sleuth.watch(
"google.appengine.api.datastore.Get") as datastore_get:
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
self.assertEqual(
"Banana",
CachingTestModel.objects.get(pk=instance.pk).field1)
self.assertTrue(datastore_get.called)
def test_transactional_save_wipes_the_cache_only_after_its_result_is_consistently_available(self):
entity_data = {
"field1": "old",
}
identifiers = caching._apply_namespace(
unique_utils.unique_identifiers_from_entity(
CachingTestModel, FakeEntity(entity_data, id=222)
),
DEFAULT_NAMESPACE,
)
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
instance = CachingTestModel.objects.create(id=222, **entity_data)
for identifier in identifiers:
self.assertEqual("old", cache.get(identifier)["field1"])
@non_transactional
def non_transactional_read(instance_pk):
CachingTestModel.objects.get(pk=instance_pk)
with transaction.atomic():
instance.field1 = "new"
instance.save()
non_transactional_read(instance.pk) # could potentially recache the old object
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
def test_save_wipes_entity_from_cache_inside_transaction(self):
entity_data = {
"field1": "Apple",
"comb1": 1,
"comb2": "Cherry"
}
identifiers = caching._apply_namespace(
unique_utils.unique_identifiers_from_entity(CachingTestModel, FakeEntity(entity_data, id=222)),
DEFAULT_NAMESPACE,
)
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
instance = CachingTestModel.objects.create(id=222, **entity_data)
for identifier in identifiers:
self.assertEqual(entity_data, cache.get(identifier))
with transaction.atomic():
instance.save()
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
def test_save_inside_transaction_evicts_cache(self):
entity_data = {
"field1": "Apple",
"comb1": 1,
"comb2": "Cherry"
}
identifiers = caching._apply_namespace(
unique_utils.unique_identifiers_from_entity(CachingTestModel, FakeEntity(entity_data, id=222)),
DEFAULT_NAMESPACE,
)
instance = CachingTestModel.objects.create(id=222, **entity_data)
for identifier in identifiers:
self.assertEqual(entity_data, cache.get(identifier))
with transaction.atomic():
instance.field1 = "Banana"
instance.save()
# Make sure that altering inside the transaction evicted the item from the cache
# and that a get then hits the datastore (which then in turn caches)
with sleuth.watch("google.appengine.api.datastore.Get") as datastore_get:
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
self.assertEqual("Banana", CachingTestModel.objects.get(pk=instance.pk).field1)
self.assertTrue(datastore_get.called)
def test_consistent_read_updates_memcache_outside_transaction(self):
entity_data = {"field1": "Apple", "comb1": 1, "comb2": "Cherry"}
identifiers = caching._apply_namespace(
unique_utils.unique_identifiers_from_entity(CachingTestModel, FakeEntity(entity_data, id=222)),
DEFAULT_NAMESPACE,
)
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
instance = CachingTestModel.objects.create(id=222, **entity_data)
instance.refresh_from_db() # Add to memcache (consistent Get)
for identifier in identifiers:
self.assertEqual(entity_data, cache.get(identifier))
cache.clear()
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
CachingTestModel.objects.get(id=222) # Consistent read
for identifier in identifiers:
self.assertEqual(entity_data, cache.get(identifier))
def test_consistent_read_updates_memcache_outside_transaction(self):
entity_data = {"field1": "Apple", "comb1": 1, "comb2": "Cherry"}
identifiers = caching._apply_namespace(
unique_utils.unique_identifiers_from_entity(
CachingTestModel, FakeEntity(entity_data, id=222)),
DEFAULT_NAMESPACE,
)
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
CachingTestModel.objects.create(id=222, **entity_data)
for identifier in identifiers:
self.assertEqual(entity_data, cache.get(identifier))
cache.clear()
for identifier in identifiers:
self.assertIsNone(cache.get(identifier))
CachingTestModel.objects.get(id=222) # Consistent read
for identifier in identifiers:
self.assertEqual(entity_data, cache.get(identifier))
