Module command_bus 

Command Bus Module

Coordinates command handling through aggregates with event persistence and publishing.

Flow

1. Load events from EventStore for the target aggregate
2. Reconstruct aggregate state via Aggregate::from_events()
3. Handle command through Aggregate::handle() to produce new events (events leave handle() with audit = AuditMetadata::pending())
4. Stamp each event with a fully-validated AuditMetadata derived from the request-scoped CommandContext
5. Append events to EventStore with optimistic concurrency check; the store re-validates audit (defense-in-depth)
6. Publish events to EventBus for projections and side effects

Audit invariant

Every persisted event carries AuditMetadata (HIPAA §164.312(b)). dispatch requires a CommandContext argument; production code cannot omit it. Internal jobs use CommandContext::system.

Structs

CommandBus

Command bus for dispatching commands to aggregates.

CommandContext

Request-scoped context for command dispatch.

Enums

CommandBusError

Errors that can occur during command bus operations.

SnapshotPolicy

Controls whether CommandBus maintains snapshots on the command/write rehydrate path.

Type Aliases

CommandBusResult