Messaging, Kafka & Dapr
HoBo unifies app messaging behind ports, not vendor SDKs. Bindles declare topic() / queue / actor signal; Camps select backends. In-process wasm stays the default. Dapr is opt-in.
Authoring (ports only)
import { topic } from "hobo/bindles";
// Backend is Matching / Camp runtime selection — never import Kafka or Dapr clients here.
const events = topic("user-created").allow("publish");Actors use the same definition surface under native or dapr placement.
Capability map
| Capability | Role |
|---|---|
| Messaging port | Delivery guarantees, tenant scoping, in-memory adapter |
| Kafka provider | Kafka / Redpanda / MSK / Confluent capability + resource definitions |
| Optional Dapr runtime | Optional Camp runtime: ActorHost + pubsub + secretless component YAML |
| Runtime placement | Native or Dapr actor placement and signal routing |
| Junction federation | Cross-Yard topic / actor-signal federation plan (control plane + identity) |
| Messaging policy | Exactly-once, deny-Dapr, tenant quotas |
| Conformance suite | Messaging conformance against Kafka and Dapr adapters |
Fidelity honesty
| Mode | How | Label |
|---|---|---|
| Simulated | No transport / no Dapr client | simulated |
| Live harness | In-memory Kafka / Dapr test doubles | live |
| Live process | Real broker or daprd client implementing the same interfaces | live |
| Forbidden | live: true without transport/client | throws |
Never treat a boolean flag as live while still on the pure emulator.
Delivery guarantees
- Portable default: at-least-once
- Exactly-once / transactional produce are capability flags Matching and
can-deploycan require - Dead-letter after
maxDeliveryAttempts(subscription); permanent failure advances the consumer group (commit under lease — do not nack-then-commit)
Secretless + multi-tenant
- Credentials are binding refs only (
fromBinding, federation,secretRef) - Generated Dapr component YAML must not embed passwords
- Topics, consumer groups, and Dapr app-ids are tenant-scoped by default
CLI
| Command | Role |
|---|---|
hobo doctor | Reports Kafka + Dapr readiness and messaging hazards |
| Authoring | Declare topic() in the Bindle; backends are Camp/Matching choices |
Messaging plane diagnostics surface through doctor and contract/conformance suites — apps never import Kafka or Dapr clients.
Permanent non-goals
- Kafka cluster operator / managed-service UI
- Full Dapr workflow engine parity (supported: activity-name map only)
- Advanced schema-registry Avro/Protobuf wire protocol end-to-end
- Junction data-plane byte relay (control-plane federation is in; overlay carries data)
Related
ActorHost · Queue · Component hosts · Capability map · CLI · WASM & WIT