Infrastructure Monitor

Set up comprehensive monitoring and observability.

Quick Start

Use Prometheus for metrics, Grafana for dashboards, Loki for logs, set up alerts for critical issues.

Instructions

Metrics with Prometheus

Application instrumentation:

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();
});

Prometheus config:

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

Dashboards with Grafana

Key metrics to monitor:

• Request rate (requests/second)
• Error rate (errors/total requests)
• Response time (p50, p95, p99)
• CPU and memory usage
• Database query time

Logging with Loki

Structured logging:

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 });

Alerting

Alert rules:

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"

Best Practices

• Monitor golden signals (latency, traffic, errors, saturation)
• Set up actionable alerts
• Use log aggregation
• Implement distributed tracing
• Create runbooks for alerts
• Regular dashboard reviews