def construct_item_args(self, domain_event):
"""
Constructs attributes of a sequenced item from the given domain event.
"""
# Copy the state of the event.
event_attrs = domain_event.__dict__.copy()
# Get the sequence ID.
sequence_id = event_attrs.get(self.sequence_id_attr_name)
# Get the position in the sequence.
position = event_attrs.get(self.position_attr_name)
# Get the topic from the event attrs, otherwise from the class.
topic = get_topic(domain_event.__class__)
# Serialise the remaining event attribute values.
data = json_dumps(event_attrs, cls=self.json_encoder_class)
# Encrypt data.
if self.cipher:
data = self.cipher.encrypt(data)
# Get the 'other' args.
# - these are meant to be derivative of the other attributes,
# to populate database fields, and shouldn't affect the hash.
other_args = tuple((getattr(domain_event, name) for name in self.other_attr_names))
return (sequence_id, position, topic, data) + other_args
def construct_event_records(self,
pending_events,
causal_dependencies=None):
# Convert to event records.
sequenced_items = self.event_store.item_from_event(pending_events)
event_records = self.event_store.record_manager.to_records(
sequenced_items)
# Set notification log IDs, and causal dependencies.
if len(event_records):
# Todo: Maybe keep track of what this probably is, to avoid query. Like log reader, invalidate on error.
if self.set_notification_ids:
current_max = self.event_store.record_manager.get_max_record_id(
) or 0
for domain_event, event_record in zip(pending_events,
event_records):
if type(domain_event).__notifiable__:
current_max += 1
event_record.id = current_max
else:
event_record.id = 'event-not-notifiable'
if self.use_causal_dependencies:
assert hasattr(self.event_store.record_manager.record_class,
'causal_dependencies')
causal_dependencies = json_dumps(causal_dependencies)
# Only need first event to carry the dependencies.
event_records[0].causal_dependencies = causal_dependencies
return event_records
def construct_event_records(self, aggregates, causal_dependencies):
assert isinstance(aggregates, (list, tuple))
record_manager = self.event_store.record_manager
assert isinstance(record_manager, RelationalRecordManager)
pending_events = []
for aggregate in aggregates:
pending_events += aggregate.__batch_pending_events__()
# Sort the events by timestamp.
pending_events.sort(key=lambda x: x.timestamp)
# Convert to event records.
sequenced_items = self.event_store.to_sequenced_item(pending_events)
event_records = record_manager.to_records(sequenced_items)
# Set notification log IDs, and causal dependencies.
if len(event_records):
current_max = record_manager.get_max_record_id() or 0
for event_record in event_records:
current_max += 1
event_record.id = current_max
# Only need first event to carry the dependencies.
if hasattr(record_manager.record_class, 'causal_dependencies'):
causal_dependencies = json_dumps(causal_dependencies)
event_records[0].causal_dependencies = causal_dependencies
return event_records
def get_item_topic_and_state(self, domain_event_class, event_attrs):
# Get the topic from the event attrs, otherwise from the class.
topic = get_topic(domain_event_class)
# Serialise the event attributes.
state = json_dumps(event_attrs, cls=self.json_encoder_class)
# Encrypt serialised state.
if self.cipher:
state = self.cipher.encrypt(state)
return topic, state
def hash_object(json_encoder_class, obj):
"""
Calculates SHA-256 hash of JSON encoded 'obj'.
:param obj: Object to be hashed.
:return: SHA-256 as hexadecimal string.
:rtype str
"""
s = json_dumps(
(obj, SALT_FOR_DATA_INTEGRITY),
cls=json_encoder_class,
)
return hashlib.sha256(s.encode()).hexdigest()
def present_section(self, section_id):
"""
Returns a section of notification log in JSON format.
:param section_id: ID of the section of the notification log.
:return: Identified section of notification log in JSON format.
:rtype: str
"""
section = self.notification_log[section_id]
is_archived = bool(section.next_id)
section_json = json_dumps(section.__dict__, self.json_encoder_class)
return section_json, is_archived
def construct_event_records(self, pending_events, causal_dependencies=None):
# Convert to event records.
sequenced_items = self.event_store.to_sequenced_item(pending_events)
event_records = self.event_store.record_manager.to_records(sequenced_items)
# Set notification log IDs, and causal dependencies.
if len(event_records):
current_max = self.event_store.record_manager.get_max_record_id() or 0
for domain_event, event_record in zip(pending_events, event_records):
if type(domain_event).__notifiable__:
current_max += 1
event_record.id = current_max
else:
event_record.id = ''
# Only need first event to carry the dependencies.
if hasattr(self.event_store.record_manager.record_class, 'causal_dependencies'):
causal_dependencies = json_dumps(causal_dependencies)
event_records[0].causal_dependencies = causal_dependencies
return event_records
def present_section(self, section_id):
section = self.notification_log[section_id]
is_archived = bool(section.next_id)
section_json = json_dumps(section.__dict__, self.json_encoder_class)
return section_json, is_archived
def hash_object(json_encoder_class, obj):
s = json_dumps(
(obj, SALT_FOR_DATA_INTEGRITY),
cls=json_encoder_class,
)
return hashlib.sha256(s.encode()).hexdigest()
