import pino from 'pino';
import { randomUUID } from 'crypto';

const logger = pino({
  level: process.env.LOG_LEVEL || 'info',
  formatters: {
    level: (label) => ({ level: label }),
  },
  timestamp: pino.stdTimeFunctions.isoTime,
  base: {
    service: 'checkout-api',
    version: process.env.APP_VERSION,
    env: process.env.NODE_ENV
  }
});

// Middleware — adds request context
app.use((req, res, next) => {
  req.log = logger.child({
    request_id: randomUUID(),
    method: req.method,
    path: req.path,
    user_id: req.user?.id
  });
  next();
});

// Usage
app.post('/checkout', async (req, res) => {
  req.log.info('Checkout initiated', {
    cart_id: req.body.cart_id,
    item_count: req.body.items.length,
    total: req.body.total
  });

  try {
    const result = await processPayment(req.body);
    req.log.info('Payment successful', {
      order_id: result.order_id,
      payment_id: result.payment_id,
      latency_ms: Date.now() - req.startTime
    });
    res.json(result);
  } catch (error) {
    req.log.error('Payment failed', {
      error_message: error.message,
      error_code: error.code,
      latency_ms: Date.now() - req.startTime
    });
    res.status(500).json({ error: 'Payment failed' });
  }
});
Logging — ELK Stack, Structured Logging

Logging — ELK Stack, Structured Logging

Logging — ELK Stack, Structured Logging
