Initial NixPanel Build

server/src/core/system.ts

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+import { readFile } from 'fs/promises'
+import { exec } from './exec.js'
+import type { SystemStats, ServiceStatus } from '../types/index.js'
+
+/**
+ * Read CPU usage (0-100%) from /proc/stat.
+ */
+async function getCpuUsage(): Promise<number> {
+  try {
+    const stat1 = await readFile('/proc/stat', 'utf8')
+    await new Promise(r => setTimeout(r, 200))
+    const stat2 = await readFile('/proc/stat', 'utf8')
+
+    const parse = (s: string) => {
+      const line = s.split('\n')[0].split(' ').filter(Boolean).slice(1).map(Number)
+      const idle = line[3] + line[4]
+      const total = line.reduce((a, b) => a + b, 0)
+      return { idle, total }
+    }
+
+    const s1 = parse(stat1)
+    const s2 = parse(stat2)
+    const idleDiff = s2.idle - s1.idle
+    const totalDiff = s2.total - s1.total
+    return Math.round((1 - idleDiff / totalDiff) * 100)
+  } catch {
+    return 0
+  }
+}
+
+/**
+ * Get memory stats from /proc/meminfo (bytes).
+ */
+async function getMemoryStats(): Promise<SystemStats['memory']> {
+  try {
+    const content = await readFile('/proc/meminfo', 'utf8')
+    const get = (key: string) => {
+      const match = content.match(new RegExp(`${key}:\\s+(\\d+)\\s+kB`))
+      return match ? parseInt(match[1], 10) * 1024 : 0
+    }
+    const total = get('MemTotal')
+    const free = get('MemFree')
+    const buffers = get('Buffers')
+    const cached = get('Cached')
+    const used = total - free - buffers - cached
+    return {
+      total,
+      used,
+      free: total - used,
+      percent: Math.round((used / total) * 100),
+    }
+  } catch {
+    return { total: 0, used: 0, free: 0, percent: 0 }
+  }
+}
+
+/**
+ * Get disk usage for / (bytes).
+ */
+async function getDiskStats(): Promise<SystemStats['disk']> {
+  try {
+    const result = await exec('df', ['-B1', '/'])
+    const lines = result.stdout.split('\n')
+    const parts = lines[1]?.split(/\s+/)
+    if (!parts) return { total: 0, used: 0, free: 0, percent: 0 }
+    const total = parseInt(parts[1], 10)
+    const used = parseInt(parts[2], 10)
+    const free = parseInt(parts[3], 10)
+    return { total, used, free, percent: Math.round((used / total) * 100) }
+  } catch {
+    return { total: 0, used: 0, free: 0, percent: 0 }
+  }
+}
+
+/**
+ * Get system load averages from /proc/loadavg.
+ */
+async function getLoadAvg(): Promise<[number, number, number]> {
+  try {
+    const content = await readFile('/proc/loadavg', 'utf8')
+    const parts = content.split(' ')
+    return [parseFloat(parts[0]), parseFloat(parts[1]), parseFloat(parts[2])]
+  } catch {
+    return [0, 0, 0]
+  }
+}
+
+/**
+ * Gather all system stats in parallel.
+ */
+export async function getSystemStats(): Promise<SystemStats> {
+  const [cpu, memory, disk, load] = await Promise.all([
+    getCpuUsage(),
+    getMemoryStats(),
+    getDiskStats(),
+    getLoadAvg(),
+  ])
+
+  return {
+    cpu,
+    memory,
+    disk,
+    load,
+    uptime: Math.floor(process.uptime()),
+  }
+}
+
+/**
+ * Check the status of a systemd service.
+ */
+export async function getServiceStatus(name: string): Promise<ServiceStatus> {
+  const [activeResult, enabledResult] = await Promise.all([
+    exec('systemctl', ['is-active', name]),
+    exec('systemctl', ['is-enabled', name]),
+  ])
+
+  const active = activeResult.stdout.trim()
+  const enabled = enabledResult.stdout.trim() === 'enabled'
+
+  let status: ServiceStatus['status'] = 'unknown'
+  if (active === 'active') status = 'running'
+  else if (active === 'inactive') status = 'stopped'
+  else if (active === 'failed') status = 'failed'
+
+  return { name, status, enabled }
+}
+
+export const MANAGED_SERVICES = [
+  'nginx', 'apache2', 'mysql', 'mariadb',
+  'postfix', 'dovecot', 'vsftpd', 'bind9',
+  'fail2ban', 'ufw', 'cron', 'ssh',
+]