import os
from eventsourcing.application.policies import PersistencePolicy, SnapshottingPolicy
from eventsourcing.domain.model.entity import DomainEntity
from eventsourcing.domain.model.snapshot import Snapshot
from eventsourcing.infrastructure.eventsourcedrepository import EventSourcedRepository
from eventsourcing.infrastructure.eventstore import EventStore
from eventsourcing.infrastructure.sequenceditemmapper import SequencedItemMapper
from eventsourcing.infrastructure.snapshotting import EventSourcedSnapshotStrategy
from eventsourcing.infrastructure.sqlalchemy.datastore import SQLAlchemyDatastore, SQLAlchemySettings
from eventsourcing.infrastructure.sqlalchemy.factory import construct_sqlalchemy_eventstore
from eventsourcing.infrastructure.sqlalchemy.manager import SQLAlchemyRecordManager
from eventsourcing.infrastructure.sqlalchemy.records import SnapshotRecord
from eventsourcing.interface.notificationlog import RecordManagerNotificationLog
from eventsourcing.utils.cipher.aes import AESCipher
from eventsourcing.utils.random import decode_random_bytes
from eventsourcing.utils.uuids import uuid_from_application_name
[docs]class SimpleApplication(object):
persist_event_type = None
def __init__(self, name='', persistence_policy=None, persist_event_type=None, uri=None, pool_size=5, session=None,
cipher_key=None, sequenced_item_class=None, stored_event_record_class=None, setup_table=True,
contiguous_record_ids=True, pipeline_id=-1, notification_log_section_size=None):
self.notification_log_section_size = notification_log_section_size
self.name = name or type(self).__name__.lower()
# Setup cipher (optional).
self.setup_cipher(cipher_key)
# Setup connection to database.
self.setup_datastore(session, uri, pool_size)
# Setup the event store.
self.sequenced_item_class = sequenced_item_class
self.stored_event_record_class = stored_event_record_class
self.contiguous_record_ids = contiguous_record_ids
self.application_id = uuid_from_application_name(self.name)
self.pipeline_id = pipeline_id
self.setup_event_store()
# Setup notifications.
self.notification_log = RecordManagerNotificationLog(
self.event_store.record_manager,
section_size=self.notification_log_section_size
)
# Setup an event sourced repository.
self.setup_repository()
# Setup a persistence policy.
self.persistence_policy = persistence_policy
if self.persistence_policy is None:
self.setup_persistence_policy(persist_event_type or type(self).persist_event_type)
# Setup table in database.
if setup_table and not session:
self.setup_table()
[docs] def change_pipeline(self, pipeline_id):
self.pipeline_id = pipeline_id
self.event_store.record_manager.pipeline_id = pipeline_id
@property
def session(self):
return self.datastore.session
[docs] def setup_cipher(self, cipher_key):
cipher_key = decode_random_bytes(cipher_key or os.getenv('CIPHER_KEY', ''))
self.cipher = AESCipher(cipher_key) if cipher_key else None
[docs] def setup_datastore(self, session, uri, pool_size=5):
self.datastore = SQLAlchemyDatastore(
settings=SQLAlchemySettings(uri=uri, pool_size=pool_size),
session=session,
)
[docs] def setup_event_store(self):
# Construct event store.
self.event_store = self.construct_event_store(self.application_id, self.pipeline_id)
[docs] def construct_event_store(self, application_id, pipeline_id):
return construct_sqlalchemy_eventstore(
sequenced_item_class=self.sequenced_item_class,
session=self.datastore.session,
cipher=self.cipher,
record_class=self.stored_event_record_class,
contiguous_record_ids=self.contiguous_record_ids,
application_id=application_id,
pipeline_id=pipeline_id,
)
[docs] def setup_repository(self, **kwargs):
event_store = self.event_store
self.repository = self.construct_repository(event_store, **kwargs)
[docs] def construct_repository(self, event_store, **kwargs):
return EventSourcedRepository(
event_store=event_store,
**kwargs
)
[docs] def setup_persistence_policy(self, persist_event_type):
self.persistence_policy = PersistencePolicy(
event_store=self.event_store,
event_type=persist_event_type
)
[docs] def setup_table(self):
# Setup the database table using event store's record class.
self.datastore.setup_table(
self.event_store.record_manager.record_class
)
[docs] def drop_table(self):
# Setup the database table using event store's record class.
self.datastore.drop_table(
self.event_store.record_manager.record_class
)
[docs] def close(self):
# Close the persistence policy.
if self.persistence_policy:
self.persistence_policy.close()
# Close database connection.
self.datastore.close_connection()
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
self.close()
[docs]class SnapshottingApplication(SimpleApplication):
def __init__(self, period=10, snapshot_record_class=None, **kwargs):
self.period = period
self.snapshot_record_class = snapshot_record_class
super(SnapshottingApplication, self).__init__(**kwargs)
[docs] def setup_event_store(self):
super(SnapshottingApplication, self).setup_event_store()
# Setup snapshot store, using datastore session, and SnapshotRecord class.
# Todo: Refactor this into a new create_sqlalchemy_snapshotstore() function.
self.snapshot_store = EventStore(
SQLAlchemyRecordManager(
session=self.datastore.session,
record_class=self.snapshot_record_class or SnapshotRecord
),
SequencedItemMapper(
sequence_id_attr_name='originator_id',
position_attr_name='originator_version'
)
)
[docs] 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
)
[docs] def setup_persistence_policy(self, persist_event_type):
persist_event_type = persist_event_type or DomainEntity.Event
super(SnapshottingApplication, self).setup_persistence_policy(persist_event_type)
self.snapshotting_policy = SnapshottingPolicy(self.repository, self.period)
self.snapshot_persistence_policy = PersistencePolicy(
event_store=self.snapshot_store,
event_type=Snapshot
)
[docs] def setup_table(self):
super(SnapshottingApplication, self).setup_table()
# Also setup snapshot table.
self.datastore.setup_table(self.snapshot_store.record_manager.record_class)
[docs] def close(self):
super(SnapshottingApplication, self).close()
self.snapshotting_policy.close()
self.snapshot_persistence_policy.close()