express-insights/stats.js

Production-ready Express middleware for backend health monitoring with metrics, HTML/JSON output, authentication, and service checks.

const { formatBytes, formatUptime, getDiskUsage, getNetworkInterfaces, getProcessInfo, getEnhancedSystemStats } = require('./utils');

const cache = new Map();

async function getDefaultStats(options = {}) {
  const { version, includeNetwork, includeDisk, cacheTTL, resourceThresholds } = options;
  const cacheKey = `default-stats:${includeNetwork}:${includeDisk}`;
  const now = Date.now();

  if (cache.has(cacheKey)) {
    const cached = cache.get(cacheKey);
    if (now - cached.timestamp < cacheTTL) {
      return { ...cached.data, timestamp: new Date() };
    }
  }

  const memUsage = process.memoryUsage();
  const stats = {
    status: 'healthy',
    uptime: formatUptime(process.uptime()),
    timestamp: new Date(),
    version: version || '1.0.0',
    environment: process.env.NODE_ENV || 'development',
    memory: {
      rss: formatBytes(memUsage.rss),
      heapTotal: formatBytes(memUsage.heapTotal),
      heapUsed: formatBytes(memUsage.heapUsed),
      external: formatBytes(memUsage.external),
      arrayBuffers: formatBytes(memUsage.arrayBuffers || 0),
      heapUsedPercent: ((memUsage.heapUsed / memUsage.heapTotal) * 100).toFixed(2) + '%',
    },
    system: getEnhancedSystemStats(resourceThresholds),
    process: getProcessInfo(),
  };

  if (includeNetwork) stats.network = getNetworkInterfaces();
  if (includeDisk) stats.disk = await getDiskUsage();

  cache.set(cacheKey, { data: stats, timestamp: now });
  return stats;
}

module.exports = { getDefaultStats };