const prometheus = require('prom-client');

const httpRequestDuration = new prometheus.Histogram({
  name: 'http_request_duration_seconds',
  help: 'Duration of HTTP requests in seconds',
  labelNames: ['method', 'route', 'status_code']
});

app.use((req, res, next) => {
  const start = Date.now();
  res.on('finish', () => {
    const duration = (Date.now() - start) / 1000;
    httpRequestDuration.labels(req.method, req.route?.path, res.statusCode).observe(duration);
  });
  next();
});

scrape_configs:
  - job_name: 'app'
    static_configs:
      - targets: ['app:3000']
    scrape_interval: 15s

const winston = require('winston');

const logger = winston.createLogger({
  format: winston.format.json(),
  transports: [
    new winston.transports.Console()
  ]
});

logger.info('User logged in', { userId: user.id, ip: req.ip });

groups:
  - name: app_alerts
    rules:
      - alert: HighErrorRate
        expr: rate(http_requests_total{status=~"5.."}[5m]) > 0.05
        for: 5m
        annotations:
          summary: "High error rate detected"