@elastic/synthetics/src/plugins/performance.ts

Elastic synthetic monitoring agent

/**
 * MIT License
 *
 * Copyright (c) 2020-present, Elastic NV
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

import { Driver, PageMetrics } from '../common_types';

const supportedMetrics = new Set<string>([
  'Timestamp',
  'Documents',
  'Frames',
  'JSEventListeners',
  'Nodes',
  'LayoutCount',
  'RecalcStyleCount',
  'LayoutDuration',
  'RecalcStyleDuration',
  'ScriptDuration',
  'TaskDuration',
  'JSHeapUsedSize',
  'JSHeapTotalSize',
]);

export class PerformanceManager {
  constructor(private driver: Driver) {}

  async start() {
    await this.driver.client.send('Performance.enable');
  }

  async stop() {
    await this.driver.client.send('Performance.disable');
  }

  async getMetrics() {
    const { metrics } = await this.driver.client.send('Performance.getMetrics');
    return this.buildMetricsObject(metrics);
  }

  private buildMetricsObject(metrics = []): PageMetrics {
    const result = {};
    for (const metric of metrics) {
      if (supportedMetrics.has(metric.name)) result[metric.name] = metric.value;
    }
    return result;
  }
}