Project layout

A Riverbase application keeps domain logic and process wiring in separate crates. The domain crate knows nothing about HTTP binding, ports, or config files. The service crate is a thin binary that loads configuration, builds a runtime, and mounts domains.

my-app/
├── Cargo.toml                  # workspace: members + [workspace.dependencies]
├── domain/                     # todo-domain: the bounded context
│   ├── Cargo.toml
│   ├── migrations/             # Diesel migrations for this domain's tables
│   └── src/
│       ├── lib.rs              # re-exports
│       ├── domain.rs           # domain! — namespace, engine slots, spawn
│       ├── command.rs          # command_engine! — payloads, handlers, typed helpers
│       ├── aggregate.rs        # TodoAggregate — #[domain_action] methods
│       ├── query.rs            # query_resource!, report_resource!, query_engine!
│       ├── service.rs          # optional service engine (non-CQRS capabilities)
│       └── postgres/
│           ├── schema.rs       # diesel table! with shared domain fields
│           ├── entity.rs       # domain_row! + pg_domain_entity!
│           ├── migrate.rs      # embedded migrations
│           └── mod.rs          # DomainStoreSpec for the domain
└── service/                    # todo-service: the binary
    ├── Cargo.toml
    ├── riverbase.toml          # service defaults (env vars override)
    └── src/main.rs             # RiverbaseApp::init → DomainRuntime → spawn → mount → serve

This is the layout the Tutorial builds. The Quick start keeps the same files in one crate, which is fine while there is one domain. A split deployment adds one more binary crate (split/) that mounts the same domain as two processes. See Deployment.

Start a new domain

Copy the quick start's files into a new domain crate and rename the resource. Every domain needs the same six pieces: a query resource, a command engine, an aggregate, a Diesel entity with its migration, a store spec, and the domain! declaration.

Replace the starter policy

The quick start declares policy: public(...) because it has no tenants. Replace it with a real row policy before production. See Multi-tenancy.

Dependency direction

Keep it one-way:

• The domain crate depends on riverbase_core and riverbase_proc. Gate anything that needs axum (RxDB collections, Casbin helpers) behind an optional http feature, as todo-domain does.
• The service crate depends on riverbase_http and the domain crates it mounts.
• Domains never depend on each other's crates. Cross-domain calls go through the command invoker or integration messages. See Domains and namespacing.

Next: Configuration.