Lesson 01 Livebook: Order

This notebook keeps chapter 1 focused on the first GTA rule:

> if a shipment fails validation, it is legally considered never to have existed

Mix.install([
  {:galactic_trade_authority, path: "../01_order"}
])

Build The First Official Shipment

state = GalacticTradeAuthority.bootstrap_registry!()

%{
  trader: state.trader.callsign,
  route: {state.origin_planet.name, state.destination_planet.name},
  resource: state.resource.name,
  manifest: state.shipment.manifest_number,
  shipment_count: Enum.count(GalacticTradeAuthority.list_shipments!())
}

Inspect The Failure Surface

try do
  GalacticTradeAuthority.Resources.Shipment.register!(%{
    manifest_number: "BAD-42",
    quantity: 0,
    declared_value: -10,
    trader_id: state.trader.id,
    origin_planet_id: state.origin_planet.id,
    destination_planet_id: state.origin_planet.id,
    resource_id: state.resource.id
  })
rescue
  error in Ash.Error.Invalid ->
    error.errors
    |> Enum.map(&Exception.message/1)
end

The registry does not store a bad shipment and clean it up later. It refuses to make that shipment real.