Workers

Workers are internal background processes that consume Kafka events produced by the platform's microservices. They have no public REST API — each exposes GET /status (health check) and GET /metrics (Prometheus); the dispatcher additionally serves its BullMQ dashboard at /bullmq and Swagger at /api.

Overview

Worker Summary

Worker	Port	Role
Dispatcher	4010	Routes MongoDB change events to client webhooks via BullMQ retry queues
Observer	4020	Aggregates create/update/delete statistics into special/stats
Preserver	4030	EMQX ExHook gRPC server — handles MQTT auth and session lifecycle
Watcher	4040	Syncs grants, APTs, clients, users and configs into Redis, and products, messages and posts into Elasticsearch
Publisher	4050	Publishes MQTT messages to EMQX for entity owner/share/client topics
Logger	4060	Persists audit log entries from Kafka to PostgreSQL
Cleaner	4070	Purges expired records from MongoDB, PostgreSQL, and Redis

Internal Structure

Most workers share this layout:

apps/workers/<name>/src/
├── main.ts              # HTTP health server + Kafka consumer bootstrap
├── app.module.ts        # Root module — DB connections, BullMQ, Kafka clients
├── app.controller.ts    # HTTP: /status, /metrics
├── app.service.ts       # Core business logic invoked by processor/controller
├── app.processor.ts     # @Process() — BullMQ job handler (dispatcher only)
├── app.task.ts          # @Timeout()/@Cron() — scheduled tasks
└── modules/
    └── <domain>/
        └── <entity>/    # Domain-scoped sub-modules

Health Check

Every worker exposes /status:

curl http://localhost:4010/status    # dispatcher
curl http://localhost:4020/status    # observer
curl http://localhost:4030/status    # preserver
curl http://localhost:4040/status    # watcher
curl http://localhost:4050/status    # publisher
curl http://localhost:4060/status    # logger
curl http://localhost:4070/status    # cleaner

Possible dependencies reported: redis, mongo, pgsql, kafka.