State 007 Fidelity Profile
This profile captures the required technical shape for state 005-messaging-nats-replacement.
Runtime Stack Deltas From State 003
| Concern | State 003 | State 007 |
|---|---|---|
| Messaging backbone | trade-feed (Socket.IO service) | nats-broker (NATS container) |
| Backend pub/sub protocol | Socket.IO semantics | NATS subjects |
| Browser real-time stream | Socket.IO websocket path | nats.ws websocket path via ingress |
| Ingress | NGINX | NGINX (extended with /nats-ws) |
| Runtime model | Docker Compose | Docker Compose |
NATS Baseline Constraints
- Broker image should be lightweight and local-friendly (
nats:2.x). - Compose service exposes:
4222(client TCP),8222(monitoring, optional local debug),- websocket endpoint mapped via ingress path.
- Subject conventions are defined in
system/messaging-subject-map.md.
Closeness Policy
State 007 is intentionally not source-close to the old trade-feed implementation; it is architecture-close to state 003 except for the messaging layer replacement.
Changes expected:
- removal of
trade-feedruntime component, - introduction of NATS client wiring in producer/consumer services,
- frontend stream client migration.