def test_successful_transaction():
messages = list(make_batch_messages(batch_identifier, [
{'begin_operation': begin},
{'mutation_operation': mutation},
{'commit_operation': commit},
]))
state = None
state = reserialize(validate_transaction_state(state, 0, messages[0]))
assert get_oneof_value(state, 'state') == (
InTransaction(
publisher=messages[0].header.publisher,
batch_identifier=batch_identifier
)
)
state = reserialize(validate_transaction_state(state, 1, messages[1]))
assert get_oneof_value(state, 'state') == (
InTransaction(
publisher=messages[1].header.publisher,
batch_identifier=batch_identifier
)
)
state = reserialize(validate_transaction_state(state, 2, messages[2]))
assert get_oneof_value(state, 'state') == (
Committed(
publisher=messages[2].header.publisher,
batch_identifier=batch_identifier
)
)
def test_publisher_failure():
messages = []
publisher = Publisher(messages.extend)
with pytest.raises(NotImplementedError):
with publisher.batch(batch_identifier, begin):
raise NotImplementedError
published_messages = map(reserialize, messages)
assert get_oneof_value(
get_oneof_value(published_messages[0], 'operation'),
'operation'
) == begin
assert get_oneof_value(
get_oneof_value(published_messages[1], 'operation'),
'operation'
) == rollback
# Ensure it actually generates valid data.
state = None
for offset, message in enumerate(published_messages):
state = reserialize(validate_state(state, offset, message))
for i, message in enumerate(published_messages):
assert message.header.publisher == publisher.id
assert message.header.sequence == i
# Write another message to ensure that the publisher can continue to be used.
assert len(messages) == 2
publisher.publish()
assert len(messages) == 3
assert messages[2].header.sequence == 2
def __call__(self, state, offset, message):
if state is not None:
state = get_oneof_value(state, "state")
operation = get_oneof_value(get_oneof_value(message, "operation"), "operation")
state_cls = type(state) if state is not None else None
try:
receivers = self.receivers[state_cls]
except KeyError:
raise InvalidEventError("Cannot receive events in state: {0!r}".format(state))
try:
receiver = receivers[type(operation)]
except KeyError:
raise InvalidEventError(
"Cannot receive {0!r} while in state: {1!r}".format(operation, state), expected=set(receivers.keys())
)
return self.message(**receiver(state, offset, message))
def test_publisher():
messages = []
publisher = Publisher(messages.extend)
with publisher.batch(batch_identifier, begin) as publish:
publish(mutation)
published_messages = map(reserialize, messages)
assert get_oneof_value(
get_oneof_value(published_messages[0], 'operation'),
'operation'
) == begin
assert get_oneof_value(
get_oneof_value(published_messages[1], 'operation'),
'operation'
) == mutation
assert get_oneof_value(
get_oneof_value(published_messages[2], 'operation'),
'operation'
) == commit
for i, message in enumerate(published_messages):
assert message.header.publisher == publisher.id
assert message.header.sequence == i
# Ensure it actually generates valid data.
state = None
for offset, message in enumerate(published_messages):
state = reserialize(validate_state(state, offset, message))
def run(self, loader, stream):
state = self.get_state()
if state is None:
logger.info('Bootstrapping new replication target with %s...', loader)
with loader.fetch() as (bootstrap_state, loaders):
for table, records in loaders:
logger.info('Loading records from %s...', table.name)
self.load(table, records)
state = State(bootstrap_state=bootstrap_state)
self.commit(state)
logger.debug(
'Successfully bootstrapped from %s using snapshot: %s',
uuid.UUID(bytes=bootstrap_state.node).hex,
FormattedSnapshot(bootstrap_state.snapshot),
)
logger.info('Starting to consume from %s...', stream)
for state, offset, message in stream.consume(state):
operation = get_oneof_value(message.batch_operation, 'operation')
if isinstance(operation, BeginOperation):
logger.debug(
'Beginning %s (%s to %s)...',
FormattedBatchIdentifier(message.batch_operation.batch_identifier),
FormattedSnapshot(operation.start.snapshot),
FormattedSnapshot(operation.end.snapshot),
)
elif isinstance(operation, MutationOperation):
# Skip any messages that were part of the bootstrap snapshot.
if state.HasField('bootstrap_state') and txid_visible_in_snapshot(operation.transaction, state.bootstrap_state.snapshot):
logger.debug('Skipping operation that was visible in bootstrap snapshot.')
else:
self.apply(state, operation)
elif isinstance(operation, CommitOperation):
logger.info(
'Committing %s.',
FormattedBatchIdentifier(message.batch_operation.batch_identifier),
)
self.commit(state)
elif isinstance(operation, RollbackOperation):
logger.info(
'Rolling back %s.',
FormattedBatchIdentifier(message.batch_operation.batch_identifier),
)
self.rollback(state)
else:
raise AssertionError('Received unexpected operation!')
def validate_bootstrap_state(state, offset, message):
if state is None:
return None
# can be removed (considered "streaming") when xmin (first still running
# transaction) of start tick on same node as bootstrap is greater than or
# equal to bootstrap xmax (first unassigned txid). (this transaction
# doesn't have to succeed, it just means that the ticker has advanced past
# the end of the bootstrap snapshot) this could be a little bit more reliable
# by using commit operation but then those would have to also include the
# start/stop payloads? (not sure if that's worth it. this does also mean that
# a batch must be started, even if failed, before mode switch can occur
# which is a little weird)
# TODO: this needs to also check correct node, obv
operation = get_oneof_value(message.batch_operation, 'operation')
if isinstance(operation, BeginOperation) and operation.start.snapshot.min > state.snapshot.max:
logger.info('Caught up with replication stream!')
state = None
return state
def is_start_batch_operation(message):
"""
Is the ``message`` the start operation of a batch of mutations.
"""
value = get_oneof_value(message.batch_operation, 'operation')
return type(value) in TRANSACTION_START_EVENT_TYPES
