Health Check

The HealthModule exposes a /health endpoint for load balancers, uptime monitors, and container orchestrators (e.g., Kubernetes liveness probes).

Setup

import { Module, HealthModule } from 'next-js-backend';

@Module({
  imports: [HealthModule],
})
export class AppModule {}

Endpoints

GET /health

Returns the application health status:

{
  "status": "ok",
  "uptime": 3612,
  "timestamp": "2024-03-16T10:30:00.000Z",
  "version": "2.1.3"
}

GET /health/live

Kubernetes liveness probe — returns 200 OK if the process is alive.

GET /health/ready

Kubernetes readiness probe — returns 200 OK if the application is ready to accept traffic.

Custom Health Checks

Inject HealthService to add custom checks:

import { Injectable } from 'next-js-backend';
import { HealthService } from 'next-js-backend';

@Injectable()
export class AppHealthService {
  constructor(private readonly health: HealthService) {}

  async checkDatabase(): Promise<boolean> {
    try {
      await db.$queryRaw`SELECT 1`;
      return true;
    } catch {
      return false;
    }
  }
}

Use in Monitoring

Configure your health check monitors:

# Docker Compose health check
healthcheck:
  test: ["CMD", "curl", "-f", "http://localhost:3000/health"]
  interval: 30s
  timeout: 10s
  retries: 3

# Kubernetes liveness probe
livenessProbe:
  httpGet:
    path: /health/live
    port: 3000
  initialDelaySeconds: 30
  periodSeconds: 10