Тестирование Web Vitals и производительности

+-------------------------------------------------------------------------+
|                  GitHub Actions Runner (Ubuntu Container)               |
+-------------------------------------------------------------------------+
                                     |
                                     v 1. Build & Collect (lhci collect)
+-------------------------------------------------------------------------+
|               Next.js 15 / React Production Build Server                |
|                    pnpm build && pnpm start (Port 3000)                 |
+-------------------------------------------------------------------------+
                                     |
                                     v CDP (Chrome DevTools Protocol)
+-------------------------------------------------------------------------+
|                  Headless Chrome with Throttling Profile                |
|  - CPU Slowdown: 4x (Эмуляция мобильного процессора среднего уровня)    |
|  - Network Throttling: Fast 4G (RTT 150ms, Throughput 1.6 Mbps)         |
|  - Viewport: Mobile (360x640) or Desktop (1366x768)                     |
|  - Number of Runs: 3 (Расчет медианного прогона / Median Run)           |
+-------------------------------------------------------------------------+
                                     |
                                     v 2. Raw Trace & Performance Metrics
+-------------------------------------------------------------------------+
|                        Core Web Vitals Extractor                        |
|                                                                         |
|   LCP (Largest Contentful Paint)   <= 2.5s   -> [Pass / Fail]           |
|   CLS (Cumulative Layout Shift)    <= 0.10   -> [Pass / Fail]           |
|   INP (Interaction to Next Paint)  <= 200ms  -> [Pass / Fail]           |
|   TBT (Total Blocking Time)        <= 200ms  -> [Pass / Fail]           |
+-------------------------------------------------------------------------+
                                     |
                                     v 3. Assertions Engine (lhci assert)
+-------------------------------------------------------------------------+
|                 Resource Budget Validation (budget.json)                |
|                                                                         |
|   Total JS Bundle Size             <= 180 KB -> [Pass / Fail]           |
|   Third-party Scripts              <=  50 KB -> [Pass / Fail]           |
+-------------------------------------------------------------------------+
                                     |
                  +------------------+------------------+
                  |                                     |
               [PASS]                                [FAIL]
                  v                                     v
       PR Check: Green                 PR Check: Red / Block Merge
   Показатели в норме              Деградация LCP на 400ms (> 2.5s)

module.exports = {
  ci: {
    collect: {
      // Автоматический запуск production-сервера перед аудитом
      startServerCommand: 'pnpm run start',
      startServerReadyPattern: 'ready on http://localhost:3000',
      startServerReadyTimeout: 60000,
      url: [
        'http://localhost:3000/',
        'http://localhost:3000/catalog',
        'http://localhost:3000/pricing',
      ],
      // 3 запуска для нивелирования аппаратных колебаний виртуальной машины
      numberOfRuns: 3,
      settings: {
        // Профиль эмуляции: эмуляция мобильного устройства среднего класса
        preset: 'desktop', // или 'mobile' для строгой проверки 4x CPU Throttling
        throttlingMethod: 'simulate',
        // Отключение аудитов, нерелевантных для локального тестового сервера
        skipAudits: ['uses-http2', 'is-on-https'],
      },
    },
    assert: {
      // Использование рекомендованного базового набора правил
      preset: 'lighthouse:recommended',
      assertions: {
        // 1. Core Web Vitals: Строгие пороговые значения
        'largest-contentful-paint': ['error', { maxNumericValue: 2500 }],
        'cumulative-layout-shift': ['error', { maxNumericValue: 0.1 }],
        'total-blocking-time': ['error', { maxNumericValue: 200 }],

        // 2. Интегральные скоры категорий (от 0 до 1)
        'categories:performance': ['error', { minScore: 0.90 }],
        'categories:accessibility': ['error', { minScore: 0.95 }],
        'categories:best-practices': ['error', { minScore: 0.95 }],
        'categories:seo': ['error', { minScore: 0.95 }],

        // 3. Бюджеты ресурсов
        'resource-summary:script:size': ['error', { maxNumericValue: 180000 }], // 180 KB
        'resource-summary:total:size': ['error', { maxNumericValue: 600000 }],  // 600 KB
        'dom-size': ['error', { maxNumericValue: 1200 }],
      },
    },
    upload: {
      // Сохранение HTML-отчетов во временное хранилище LHCI или собственный сервер
      target: 'temporary-public-storage',
    },
  },
};

[
  {
    "path": "/*",
    "timings": [
      {
        "metric": "interactive",
        "budget": 3000
      },
      {
        "metric": "first-contentful-paint",
        "budget": 1200
      }
    ],
    "resourceSizes": [
      {
        "resourceType": "script",
        "budget": 180
      },
      {
        "resourceType": "stylesheet",
        "budget": 45
      },
      {
        "resourceType": "image",
        "budget": 250
      },
      {
        "resourceType": "font",
        "budget": 80
      },
      {
        "resourceType": "third-party",
        "budget": 50
      },
      {
        "resourceType": "total",
        "budget": 600
      }
    ],
    "resourceCounts": [
      {
        "resourceType": "third-party",
        "budget": 5
      },
      {
        "resourceType": "script",
        "budget": 10
      }
    ]
  }
]

/**
 * Инициализация мониторинга Core Web Vitals и замера задержек взаимодействий
 */
export function registerPerformanceObservers(): void {
  if (typeof window === 'undefined' || !('PerformanceObserver' in window)) {
    return;
  }

  try {
    // 1. Отслеживание метрики Largest Contentful Paint (LCP)
    const lcpObserver = new PerformanceObserver((entryList) => {
      const entries = entryList.getEntries();
      const lastEntry = entries[entries.length - 1];
      if (lastEntry) {
        console.info(`[Web Vitals] LCP: ${lastEntry.startTime.toFixed(2)}ms`, lastEntry);
      }
    });
    lcpObserver.observe({ type: 'largest-contentful-paint', buffered: true });

    // 2. Отслеживание Cumulative Layout Shift (CLS)
    let clsValue = 0;
    const clsObserver = new PerformanceObserver((entryList) => {
      for (const entry of entryList.getEntries()) {
        const layoutShift = entry as PerformanceEntry & { hadRecentInput?: boolean; value: number };
        // Исключаем сдвиги, вызванные прямым недавним пользовательским вводом
        if (!layoutShift.hadRecentInput) {
          clsValue += layoutShift.value;
          console.info(`[Web Vitals] Cumulative CLS: ${clsValue.toFixed(4)}`);
        }
      }
    });
    clsObserver.observe({ type: 'layout-shift', buffered: true });

    // 3. Отслеживание Interaction to Next Paint (INP) через event-timing API
    const inpObserver = new PerformanceObserver((entryList) => {
      for (const entry of entryList.getEntries()) {
        const eventEntry = entry as PerformanceEntry & {
          duration: number;
          processingStart: number;
          processingEnd: number;
          interactionId?: number;
        };

        // Логируем взаимодействия с задержкой выше критического порога 200ms
        if (eventEntry.duration > 200) {
          console.warn(
            `[Web Vitals Slow INP] Event "${eventEntry.name}" took ${eventEntry.duration.toFixed(2)}ms`,
            {
              inputDelay: eventEntry.processingStart - eventEntry.startTime,
              processingTime: eventEntry.processingEnd - eventEntry.processingStart,
              presentationDelay: eventEntry.duration - (eventEntry.processingEnd - eventEntry.startTime),
            }
          );
        }
      }
    });
    inpObserver.observe({ type: 'event', buffered: true, durationThreshold: 40 });
  } catch (err: unknown) {
    const message = err instanceof Error ? err.message : 'Unknown performance observer error';
    console.error(`Failed to register PerformanceObserver: ${message}`);
  }
}

name: Performance Quality Gate (Lighthouse CI)

on:
  pull_request:
    branches: [main]

jobs:
  lhci:
    name: Lighthouse CI Web Vitals Audit
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Setup pnpm
        uses: pnpm/action-setup@v3

      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: 22
          cache: 'pnpm'

      - name: Install dependencies
        run: pnpm install --frozen-lockfile

      - name: Build Next.js production bundle
        run: pnpm run build

      - name: Run Lighthouse CI
        env:
          LHCI_GITHUB_APP_TOKEN: ${{ secrets.LHCI_GITHUB_APP_TOKEN }}
        run: |
          pnpm exec lhci autorun

      - name: Post LHCI status comment
        if: always()
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs');
            const path = './.lighthouseci/manifest.json';
            if (fs.existsSync(path)) {
              const manifest = JSON.parse(fs.readFileSync(path, 'utf8'));
              console.log('Lighthouse CI runs completed:', manifest.length);
            }