def bootstrap(
start_orm: bool = True,
uwo: unit_of_work.AbstractUnitOfWork = unit_of_work.SqlAlchemyUnitOfWork(),
notifications: notifications.AbstractNotifications = notifications.
EmailNotification(),
publish: Callable = redis_eventpublisher.publish,
) -> messagebus.MessageBus:
if start_orm:
orm.start_mappers()
dependencies = {'uow': uow, 'send_mail': send_mail, 'publish': publish}
injected_event_handlers = {
event_type: [
inject_dependencies(handler, dependencies)
for handler in event_handlers
]
for event_type, event_handlers in handlers.EVENT_HANDLERS.items()
}
injected_command_hanlers = {
command_type: inject_dependencies(handler, dependencies)
for command_type, handler in handlers.COMMAND_HANLDERS.items()
}
return messagebus.MessageBus(
uow=uow,
event_handlers=injected_event_handlers,
command_handlers=injected_command_hanlers,
)
def bootstrap(
start_orm: bool = True,
uow: unit_of_work.AbstractUnitOfWork = unit_of_work.SqlAlchemyUnitOfWork(),
notifications: AbstractNotifications = None,
publish: Callable = redis_eventpublisher.publish,
) -> messagebus.MessageBus:
if notifications is None:
notifications = EmailNotifications()
if start_orm:
orm.start_mappers()
dependencies = {
"uow": uow,
"notifications": notifications,
"publish": publish
}
injected_event_handlers = {
event_type: [
inject_dependices(handler, dependencies)
for handler in event_handlers
]
for event_type, event_handlers in handlers.EVENT_HANDLERS.items()
}
injected_event_commands = {
command_type: inject_dependices(handler, dependencies)
for command_type, handler in handlers.COMMAND_HANDLERS.items()
}
return messagebus.MessageBus(
uow=uow,
event_handlers=injected_event_handlers,
command_handlers=injected_event_commands,
)
def test_rolls_back_uncommitted_work_by_default(sqlite_session_factory):
uow = unit_of_work.SqlAlchemyUnitOfWork(sqlite_session_factory)
with uow:
insert_batch(uow.session, "batch1", "MEDIUM-PLINTH", 100, None)
new_session = sqlite_session_factory()
rows = list(new_session.execute('SELECT * FROM "batches"'))
assert rows == []
def add_batch():
eta = request.json['eta']
if eta is not None:
eta = datetime.fromisoformat(eta).date()
services.add_batch(request.json['ref'], request.json['sku'],
request.json['qty'], eta,
unit_of_work.SqlAlchemyUnitOfWork())
return 'OK', 201
def bus(sqlite_session_factory):
bus = bootstrap.bootstrap(
start_orm=True,
uow=unit_of_work.SqlAlchemyUnitOfWork(sqlite_session_factory),
notifications=notifications.EmailNotifications(),
publish=lambda *args: None,
)
yield bus
clear_mappers()
def sqlite_bus(sqlite_session_factory):
bus = bootstrap.bootstrap(
start_orm=True,
uow=unit_of_work.SqlAlchemyUnitOfWork(sqlite_session_factory),
send_mail=lambda *args: None,
publish=lambda *args: None,
)
yield bus
clear_mappers()
def allocate_endpoint():
try:
batchref = services.allocate(request.json['orderid'],
request.json['sku'], request.json['qty'],
unit_of_work.SqlAlchemyUnitOfWork())
except (model.OutOfStock, services.InvalidSku) as e:
return jsonify({'message': str(e)}), 400
return jsonify({'batchref': batchref}), 201
def try_to_allocate(orderid, sku, exceptions):
line = models.OrderLine(orderid, sku, 10)
try:
with unit_of_work.SqlAlchemyUnitOfWork() as uow:
product = uow.products.get(sku=sku)
product.allocate(line)
time.sleep(0.2)
uow.commit()
except Exception as e:
exceptions.append(e)
def test_rolls_back_on_error(sqlite_session_factory):
class MyException(Exception):
pass
uow = unit_of_work.SqlAlchemyUnitOfWork(sqlite_session_factory)
with pytest.raises(MyException):
with uow:
insert_batch(uow.session, "batch1", "LARGE-FORK", 100, None)
raise MyException()
new_session = sqlite_session_factory()
rows = list(new_session.execute('SELECT * FROM "batches"'))
assert rows == []
def test_uow_can_retrieve_a_batch_and_allocate_to_it(sqlite_session_factory):
session = sqlite_session_factory()
insert_batch(session, "batch1", "HIPSTER-WORKBENCH", 100, None)
session.commit()
uow = unit_of_work.SqlAlchemyUnitOfWork(sqlite_session_factory)
with uow:
product = uow.products.get("HIPSTER-WORKBENCH")
line = models.OrderLine("o1", "HIPSTER-WORKBENCH", 10)
product.allocate(line)
uow.commit()
batchref = get_allocated_batch_ref(session, "o1", "HIPSTER-WORKBENCH")
assert batchref == "batch1"
def test_uow_can_retrieve_a_batch_and_allocate_to_it(session_factory):
session = session_factory()
insert_batch(session, 'batch1', 'HIPSTER-WORKBENCH', 100, None)
session.commit()
uow = unit_of_work.SqlAlchemyUnitOfWork(session_factory)
with uow:
batch = uow.batches.get(reference='batch1')
line = model.OrderLine('o1', 'HIPSTER-WORKBENCH', 10)
batch.allocate(line)
uow.commit()
batchref = get_allocated_batch_ref(session, 'o1', 'HIPSTER-WORKBENCH')
assert batchref == 'batch1'
def test_concurrent_updates_to_version_are_not_allowed(postgres_session_factory):
sku, batch = random_sku(), random_batchref()
session = postgres_session_factory()
insert_batch(session, batch, sku, 100, eta=None, product_version=1)
session.commit()
order1, order2 = random_orderid(1), random_orderid(2)
exceptions = []
try_to_allocate_order1 = lambda: try_to_allocate(order1, sku, exceptions)
try_to_allocate_order2 = lambda: try_to_allocate(order2, sku, exceptions)
thread1 = threading.Thread(target=try_to_allocate_order1)
thread2 = threading.Thread(target=try_to_allocate_order2)
thread1.start()
thread2.start()
thread1.join()
thread2.join()
[[version]] = session.execute(
"SELECT version_number FROM products WHERE sku=:sku", dict(sku=sku),
)
assert version == 2
[exception] = exceptions
assert "could not serialize access due to concurrent update" in str(exception)
orders = list(
session.execute(
"SELECT orderid FROM allocations"
" JOIN batches ON allocations.batch_id = batches.id"
" JOIN order_lines ON allocations.orderline_id = order_lines.id"
" WHERE order_lines.sku=:sku",
dict(sku=sku),
)
)
assert len(orders) == 1
with unit_of_work.SqlAlchemyUnitOfWork() as uow:
uow.session.execute("select 1")
def allocations_view_endpoint(orderid):
uow = unit_of_work.SqlAlchemyUnitOfWork()
result = views.allocations(orderid, uow)
if not result:
return 'not found', 404
return jsonify(result), 200
def handle_change_batch_quantity(m):
logging.debug('Handling %s', m)
data = json.loads(m['data'])
cmd = commands.ChangeBatchQuantity(ref=data['batchref'], qty=data['qty'])
messagebus.handle(cmd, uow=unit_of_work.SqlAlchemyUnitOfWork())
