index.js

import { SitespeedioPlugin } from "@sitespeed.io/plugin";

export default class GitLabExporterPlugin extends SitespeedioPlugin {
  constructor(options, context, queue) {
    super({ name: "gitlab-exporter", options, context, queue });
    this.results = [];
  }

  async processMessage(message) {
    const storageManager = super.getStorageManager();
    const metrics = [];

    switch (message.type) {
      case "coach.pageSummary":
        metrics.push({
          name: "Total Score",
          value: message.data.advice.performance.score,
          desiredSize: "larger",
        });

        metrics.push({
          name: "Requests",
          value: message.data.advice.info.pageRequests,
          desiredSize: "smaller",
        });

        break;

      case "pagexray.pageSummary":
        metrics.push({
          name: "Transfer Size (KB)",
          value: (message.data.transferSize / 1024).toFixed(1),
          desiredSize: "smaller",
        });

        break;

      case "browsertime.pageSummary":
        metrics.push({
          name: "Speed Index",
          value: message.data.statistics.visualMetrics.SpeedIndex.p90,
          desiredSize: "smaller",
        });

        metrics.push({
          name: "First Contentful Paint",
          value:
            message.data.statistics.timings.paintTiming[
              "first-contentful-paint"
            ].p90,
          desiredSize: "smaller",
        });

        metrics.push({
          name: "Largest Contentful Paint",
          value:
            message.data.statistics.timings.largestContentfulPaint.renderTime
              .p90,
          desiredSize: "smaller",
        });

        if ("cpu" in message.data.statistics) {
          metrics.push({
            name: "Total Blocking Time",
            value: message.data.statistics.cpu.longTasks.totalBlockingTime.p90,
            desiredSize: "smaller",
          });
        }

        break;

      case "sitespeedio.render":
        storageManager
          .writeData(JSON.stringify(this.results), "performance.json")
          .catch((err) => {
            super.log(`Error writing 'performance.json': ${err}`, "error");
          });
        break;

      default:
        return;
    }

    if (message.url) {
      const urlPath = new URL(message.url);
      this.pushMetrics(this.results, urlPath.pathname, metrics);
    }
  }

  pushMetrics(results, subject, metrics) {
    for (var i = 0; i < results.length; i++) {
      if (results[i].subject === subject) {
        results[i].metrics.push(...metrics);
        return;
      }
    }

    results.push({
      subject: subject,
      metrics: metrics,
    });
  }
}