Observability

import type { NizhalObserver } from "@nizhal/server";

const observer: NizhalObserver = {
  onPull: (event) => metrics.histogram("nizhal.pull.rows", event.rowCount),
  onPush: (event) => metrics.increment("nizhal.push.mutations", event.count),
  onConflict: (event) => log.warn("merge", event),
  onError: (error, context) => log.error(error, context),
};

createNizhalServer({ ..., observer });

noopObserver is the default. safeObserver wraps user hooks so observer throws never break sync.

Stats endpoint

gatherStats(db, realtime) powers GET /nizhal/stats:

• Mutation throughput
• Active realtime subscriptions
• Queue depth signals

Protect with adminPassword() + bearer token in production.

Client status

createNizhalStatus on the client exposes sync phase and poison-quarantine outbox entries for UI/debug panels.