Health Checks

Built-in health check system with an extensible service and HTTP endpoint.

Endpoint

GET /healthz

Returns:

{ "version": "1.2.3" }

The version is read from package.json. Returns "unknown" if not available.

If any registered health check fails, the endpoint returns an HTTP 500 error.

Registering Health Checks

import { HealthcheckService } from '@zyno-io/dk-server-foundation';

class MyService {
    constructor(private hcSvc: HealthcheckService) {
        hcSvc.register('Database', async () => {
            // Throw to indicate unhealthy
            await db.rawQuery(sql`SELECT 1`);
        });
    }
}

Database Health Check

When a database class is passed to createApp(), a database health check is automatically registered. It verifies the database connection is alive.

HealthcheckService

Method	Description
register(name, fn: () => Promise<void>)	Register a named health check function. Throw to indicate failure.
check()	Run all registered health checks. Throws on first failure.
checkIndividual()	Run all checks and return per-check results: { name, status: 'ok' | 'error', error? }[].

Health Module

The HealthModule is automatically included by createApp(). It provides:

• HealthcheckService as a DI provider
• HealthcheckController at /healthz
• MetricsController at /metrics (if Prometheus exporter is enabled)