hono-proxy/src/routes/health.ts

import { Hono } from 'hono';
import { config } from '../config';

const healthApp = new Hono();

interface HealthStatus {
  status: 'healthy' | 'degraded' | 'unhealthy';
  timestamp: string;
  uptime: number;
  services: {
    backend: {
      status: 'up' | 'down';
      responseTime?: number;
      error?: string;
    };
    cache: {
      status: 'up' | 'down';
      size?: number;
    };
  };
}

// Basic health check
healthApp.get('/', async (c) => {
  const startTime = Date.now();
  const health: HealthStatus = {
    status: 'healthy',
    timestamp: new Date().toISOString(),
    uptime: process.uptime(),
    services: {
      backend: { status: 'down' },
      cache: { status: 'up' },
    },
  };

  // Check backend health
  try {
    const backendStart = Date.now();
    const response = await fetch(`${config.backendUrl}/health`, {
      signal: AbortSignal.timeout(5000), // 5 second timeout
    });
    
    if (response.ok) {
      health.services.backend = {
        status: 'up',
        responseTime: Date.now() - backendStart,
      };
    } else {
      health.services.backend = {
        status: 'down',
        error: `HTTP ${response.status}`,
      };
      health.status = 'degraded';
    }
  } catch (error) {
    health.services.backend = {
      status: 'down',
      error: error instanceof Error ? error.message : 'Unknown error',
    };
    health.status = 'degraded';
  }

  // Overall health determination
  const allServicesUp = Object.values(health.services).every(s => s.status === 'up');
  if (!allServicesUp) {
    health.status = 'degraded';
  }

  // Return appropriate status code
  const statusCode = health.status === 'healthy' ? 200 : 503;
  
  return c.json(health, statusCode);
});

// Liveness probe (for k8s)
healthApp.get('/live', (c) => {
  return c.json({ status: 'alive', timestamp: new Date().toISOString() });
});

// Readiness probe (for k8s)
healthApp.get('/ready', async (c) => {
  try {
    // Quick check if backend is reachable
    const response = await fetch(`${config.backendUrl}/health`, {
      signal: AbortSignal.timeout(2000),
    });
    
    if (response.ok) {
      return c.json({ ready: true });
    }
    
    return c.json({ ready: false, reason: 'Backend not ready' }, 503);
  } catch (error) {
    return c.json({ 
      ready: false, 
      reason: error instanceof Error ? error.message : 'Unknown error' 
    }, 503);
  }
});

export { healthApp };