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Ecommerce example

The examples/ecommerce directory shows a full composition: DomainModule, EventBus, Outbox, Discovery and RPC.

Minimal run (orders only)

run_minimal.py — Application + orders DomainModule + OpenAPI:

from urich import Application
from orders.module import orders_module

app = Application()
app.register(orders_module)
app.openapi(title="Ecommerce API", version="0.1.0")

Run: uvicorn run_minimal:app --reload, then open /docs.

Full composition (main.py)

main.py composes:

  1. Orders DomainModule — Commands/queries and domain events for orders.
  2. EventBusModule — Custom adapter (e.g. Redis) for publishing domain events.
  3. OutboxModule — Storage and publisher (e.g. Postgres + Kafka) for transactional outbox.
  4. DiscoveryModule — Static map of service names to URLs.
  5. RpcModule — Server at /rpc and client with custom transport.

Order of registration: discovery and event bus first, then domain modules, then RPC (client may need ServiceDiscovery from the container).

Orders context structure

File Purpose
domain.py Order, Inventory (dataclasses), OrderCreated, StockReserved (DomainEvents).
application.py CreateOrder, GetOrder, ReserveForOrder (multi-aggregate command), handlers with repo(s) + EventBus injection.
infrastructure.py IOrderRepository, IInventoryRepository, in-memory implementations.
module.py DomainModule("orders").aggregate(Order).aggregate(Inventory).repository(...).repository(...).command(...).on_event(...).

Pricing context (domain service and strategy via .bind())

pricing/ — Bounded context with no aggregate and no repository; only domain service and strategy registered via .bind():

File Purpose
domain.py IPricingService, IDiscountStrategy (Protocols).
infrastructure.py PricingServiceImpl, PercentDiscountStrategy.
application.py CalculatePrice command, handler that injects IPricingService.
module.py DomainModule("pricing").bind(IDiscountStrategy, ...).bind(IPricingService, ...).command(...).query(...).

Stateless context (no persistence)

stateless_module.py — A module with only commands and queries (no .aggregate(), no .repository()): commission calculator and validator. See Stateless context.