Crate oa_gateway_core

Protocol-agnostic routing engine.

The core never parses a payload and never names a protocol. Adapters map native frames onto Envelope values and subscribe through Engine. Matching is a RouteKey (topic plus optional type hint). Fan-out is try_send: a slow subscriber loses the message rather than blocking the publisher.

Adding a protocol means adding an adapter crate, not changing this one. The plugin contract is oa_gateway_adapter::Adapter; the walkthrough is docs/writing-an-adapter.md.

Modules

• engine 🔒
• envelope 🔒
• headers 🔒
  Gateway-wide envelope header names (oag.*).
• ids 🔒
  Newtypes so an adapter id, a subscription id, and a message id cannot be mixed at the call site.
• route 🔒
  Addressing key used by crate::Engine.

Structs

• AdapterId
  Id of one running adapter instance.
• ContentType
  Label for opaque payload bytes. The engine does not interpret it.
• Delivery
  One fan-out of an Envelope to one subscription.
• Engine
  Shared, protocol-neutral pub/sub router.
• EngineStats
  Running counters for publish fan-out.
• Envelope
  Protocol-agnostic unit of data that crosses the engine.
• MessageId
  Id assigned to an crate::Envelope when it is constructed.
• PublishOutcome
  Result of one Engine::publish fan-out.
• RouteKey
  Topic plus an optional type hint.
• SubId
  Id of one subscription inside one adapter.
• SubscriberKey
  Composite key for a subscription owned by one adapter.

Enums

• EngineError
  Errors from Engine::subscribe and Engine::unsubscribe.

Constants

• DEFAULT_CHANNEL_CAPACITY
  Capacity of each subscriber delivery channel.
• HDR_ID
  Envelope crate::MessageId, written on outbound frames.
• HDR_ORIGIN
  Which adapter last published this envelope onto the engine.
• HDR_TOPIC
  Engine topic, copied onto a native frame when the protocol has a place for it.
• HDR_TYPE_HINT
  Engine type hint, copied onto a native frame when present.