def setup_repository(self, **kwargs):
# Setup repository with a snapshot strategy.
self.snapshot_strategy = EventSourcedSnapshotStrategy(
event_store=self.snapshot_store)
super(SnapshottingApplication,
self).setup_repository(snapshot_strategy=self.snapshot_strategy,
**kwargs)
def construct_repository(self, **kwargs: Any) -> None:
# Setup repository with a snapshot strategy.
assert self.snapshot_store
self.snapshot_strategy = EventSourcedSnapshotStrategy(
snapshot_store=self.snapshot_store)
super(SnapshottingApplication, self).construct_repository(
snapshot_strategy=self.snapshot_strategy, **kwargs)
def __init__(self, session, **kwargs):
# Construct infrastructure objects for storing events with SQLAlchemy
entity_active_record_strategy = SQLAlchemyActiveRecordStrategy(
active_record_class=IntegerSequencedItemRecord, session=session)
snapshot_active_record_strategy = SQLAlchemyActiveRecordStrategy(
active_record_class=SnapshotRecord, session=session)
# Initialize
super(UnitOfWork, self).__init__(
entity_active_record_strategy=entity_active_record_strategy,
snapshot_active_record_strategy=snapshot_active_record_strategy,
**kwargs)
# Construct repositories
self.snapshot_strategy = EventSourcedSnapshotStrategy(
event_store=self.snapshot_event_store)
# -- User
self.users = EventSourcedRepository(
event_store=self.entity_event_store,
mutator=User._mutate,
snapshot_strategy=self.snapshot_strategy)
self.user_collections = CollectionRepository(
event_store=self.entity_event_store)
self.user_projection_policy = UserProjectionPolicy(
user_collections=self.user_collections)
self.user_snapshotting_policy = DomainSnapshottingPolicy(
repository=self.users)
def __init__(self, **kwargs):
super(ExampleApplication, self).__init__(**kwargs)
self.snapshot_strategy = EventSourcedSnapshotStrategy(
event_store=self.timestamp_entity_event_store, )
self.example_repo = ExampleRepository(
event_store=self.version_entity_event_store,
snapshot_strategy=self.snapshot_strategy,
)
def __init__(self, **kwargs):
super(KanbanApplication, self).__init__(**kwargs)
self.snapshot_strategy = None
if self.snapshot_event_store:
self.snapshot_strategy = EventSourcedSnapshotStrategy(
event_store=self.snapshot_event_store)
assert self.entity_event_store is not None
self.user_repository = UserRepository(
event_store=self.entity_event_store,
snapshot_strategy=self.snapshot_strategy,
)
def __init__(self, **kwargs):
super(ExampleApplication, self).__init__(**kwargs)
self.snapshot_strategy = None
if self.snapshot_event_store:
self.snapshot_strategy = EventSourcedSnapshotStrategy(
snapshot_store=self.snapshot_event_store, )
assert self.entity_event_store is not None
self.example_repository = ExampleRepository(
event_store=self.entity_event_store,
snapshot_strategy=self.snapshot_strategy,
)
def __init__(self, **kwargs):
session = get_session().session
entity_active_record_strategy = SQLAlchemyActiveRecordStrategy(
active_record_class=IntegerSequencedItemRecord, session=session)
snapshot_active_record_strategy = SQLAlchemyActiveRecordStrategy(
active_record_class=SnapshotRecord, session=session)
super(UnitOfWork, self).__init__(
entity_active_record_strategy=entity_active_record_strategy,
snapshot_active_record_strategy=snapshot_active_record_strategy,
**kwargs)
self.snapshot_strategy = EventSourcedSnapshotStrategy(
event_store=self.snapshot_event_store)
self.users = EventSourcedRepository(
event_store=self.entity_event_store,
mutator=User._mutate,
snapshot_strategy=self.snapshot_strategy)
self.snapshotting_policy = KanbanSnapshottingPolicy(
repository=self.users)
def test_take_snapshot(self):
self.entity_persistence_policy = PersistencePolicy(
event_store=self.entity_event_store,
event_type=VersionedEntity.Event,
)
self.snapshot_persistence_policy = PersistencePolicy(
event_store=self.snapshot_store,
event_type=Snapshot,
)
snapshot_strategy = EventSourcedSnapshotStrategy(
event_store=self.snapshot_store)
event_player = EventPlayer(event_store=self.entity_event_store,
mutator=Example._mutate,
snapshot_strategy=snapshot_strategy)
# Take a snapshot with a non-existent ID.
unregistered_id = uuid4()
# Check no snapshot is taken.
self.assertIsNone(event_player.take_snapshot(unregistered_id))
# Check no snapshot is available.
self.assertIsNone(event_player.get_snapshot(unregistered_id))
# Create a new entity.
registered_example = create_new_example(a=123, b=234)
# Take a snapshot of the new entity (no previous snapshots).
snapshot1 = event_player.take_snapshot(registered_example.id,
lt=registered_example.version)
# Check the snapshot is pegged to the last applied version.
self.assertEqual(snapshot1.originator_version, 0)
# Replay from this snapshot.
entity_from_snapshot1 = entity_from_snapshot(snapshot1)
retrieved_example = event_player.replay_entity(
registered_example.id,
initial_state=entity_from_snapshot1,
gte=entity_from_snapshot1._version)
# Check the attributes are correct.
self.assertEqual(retrieved_example.a, 123)
# Remember the version now.
version1 = retrieved_example._version
self.assertEqual(version1, 1)
# Change attribute value.
retrieved_example.a = 999
# Remember the version now.
version2 = retrieved_example._version
self.assertEqual(version2, 2)
# Change attribute value.
retrieved_example.a = 9999
# Remember the version now.
version3 = retrieved_example._version
self.assertEqual(version3, 3)
# Check the event sourced entities are correct.
retrieved_example = event_player.replay_entity(registered_example.id)
self.assertEqual(retrieved_example.a, 9999)
# Take another snapshot.
snapshot2 = event_player.take_snapshot(retrieved_example.id,
lt=retrieved_example.version)
# Replay from this snapshot.
initial_state = entity_from_snapshot(snapshot2)
retrieved_example = event_player.replay_entity(
registered_example.id,
initial_state=initial_state,
gte=initial_state._version,
)
# Check the attributes are correct.
self.assertEqual(retrieved_example.a, 9999)
# Check we can get historical state at version1.
retrieved_example = event_player.replay_entity(registered_example.id,
lt=version1)
self.assertEqual(retrieved_example.a, 123)
# Check we can get historical state at version2.
retrieved_example = event_player.replay_entity(registered_example.id,
lt=version2)
self.assertEqual(retrieved_example.a, 999)
# Check we can get historical state at version3.
retrieved_example = event_player.replay_entity(registered_example.id,
lt=version3)
self.assertEqual(retrieved_example.a, 9999)
# Similarly, check we can get historical state using a snapshot
initial_state = entity_from_snapshot(snapshot1)
retrieved_example = event_player.replay_entity(
registered_example.id,
initial_state=initial_state,
gte=initial_state._version,
lt=version2,
)
self.assertEqual(retrieved_example.a, 999)
# Discard the entity.
registered_example = event_player.replay_entity(registered_example.id)
registered_example.discard()
# Take snapshot of discarded entity.
snapshot3 = event_player.take_snapshot(registered_example.id)
self.assertIsNone(snapshot3.state)
self.assertIsNone(entity_from_snapshot(snapshot3))
def test_snapshots(self):
self.policy = CombinedPersistencePolicy(
versioned_entity_event_store=self.version_entity_event_store,
timestamped_entity_event_store=self.timestamp_entity_event_store,
)
event_player = EventPlayer(
event_store=self.version_entity_event_store,
mutator=Example.mutate,
snapshot_strategy=EventSourcedSnapshotStrategy(
event_store=self.timestamp_entity_event_store
)
)
# Take a snapshot with a non-existent ID.
self.assertIsNone(event_player.take_snapshot(uuid4()))
# Create a new entity.
registered_example = register_new_example(a=123, b=234)
# Take a snapshot.
snapshot1 = event_player.take_snapshot(registered_example.id)
# Replay from this snapshot.
initial_state = entity_from_snapshot(snapshot1)
retrieved_example = event_player.replay_entity(registered_example.id,
initial_state=initial_state,
gte=initial_state._version)
# Check the attributes are correct.
self.assertEqual(retrieved_example.a, 123)
# Remember the version now.
version1 = retrieved_example._version
# Change attribute value.
retrieved_example.a = 999
# Remember the version now.
version2 = retrieved_example._version
# Change attribute value.
retrieved_example.a = 9999
# Remember the version now.
version3 = retrieved_example._version
# Check the event sourced entities are correct.
retrieved_example = event_player.replay_entity(registered_example.id)
self.assertEqual(retrieved_example.a, 9999)
# Take another snapshot.
snapshot2 = event_player.take_snapshot(retrieved_example.id)
# Check we can replay from this snapshot.
initial_state = entity_from_snapshot(snapshot2)
retrieved_example = event_player.replay_entity(
registered_example.id,
initial_state=initial_state,
gte=initial_state._version,
)
# Check the attributes are correct.
self.assertEqual(retrieved_example.a, 9999)
# Check we can get historical state at version1.
retrieved_example = event_player.replay_entity(registered_example.id, lt=version1)
self.assertEqual(retrieved_example.a, 123)
# Check we can get historical state at version2.
retrieved_example = event_player.replay_entity(registered_example.id, lt=version2)
self.assertEqual(retrieved_example.a, 999)
# Check we can get historical state at version3.
retrieved_example = event_player.replay_entity(registered_example.id, lt=version3)
self.assertEqual(retrieved_example.a, 9999)
# Similarly, check we can get historical state using a snapshot
initial_state = entity_from_snapshot(snapshot1)
retrieved_example = event_player.replay_entity(
registered_example.id,
initial_state=initial_state,
gte=initial_state._version,
lt=version2,
)
self.assertEqual(retrieved_example.a, 999)