BasketCheckoutSaga

Submits a checked-out basket to the ordering context as an order, the classic eShop's checkout, synchronously: the checkout is done only once the ordering context has the order, so the saga calls the ordering service's command gateway (wow.peers.eshop-ordering.url) instead of sending to its command topic, the default for the rest of the shop. The call names no order id: the ordering numbers the order it creates (SO-261031-42, its order numbers' generator), and the call's request id comes from the basket's commit, so handling the commit again, after a retry or a replay, is the same request: the ordering context decides it once and answers with the same order and number, without taking another.

The order belongs to the buyer: the call carries the basket's scope, whose owner is its buyer, and the buyer as its operator, which the ordering service trusts because the call reaches its internal port, which only the platform's own services reach, from the basket service, which names itself. While the ordering service is down the call fails: the saga is retried within its subscription's budget, then the basket parks until an operator retries it.

@Sends(calls) declares the call: the Manifest lists it, so a wait chain may follow the saga into the ordering context, and the node does not start without the ordering's URL. The saga derives nothing (Unit).